<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source to the Rust file `/Users/syrusakbary/.cargo/registry/src/github.com-1ecc6299db9ec823/regex-syntax-0.6.11/src/ast/mod.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>mod.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><script src="../../../storage.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="shortcut icon" href="../../../favicon.ico"><style type="text/css">#crate-search{background-image:url("../../../down-arrow.svg");}</style></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../regex_syntax/index.html'><div class='logo-container'><img src='../../../rust-logo.png' alt='logo'></div></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span>
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</pre><div class="example-wrap"><pre class="rust ">
<span class="doccomment">/*!
Defines an abstract syntax for regular expressions.
*/</span>
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">cmp</span>::<span class="ident">Ordering</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">error</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">fmt</span>;
<span class="kw">pub</span> <span class="kw">use</span> <span class="ident">ast</span>::<span class="ident">visitor</span>::{<span class="ident">visit</span>, <span class="ident">Visitor</span>};
<span class="kw">pub</span> <span class="kw">mod</span> <span class="ident">parse</span>;
<span class="kw">pub</span> <span class="kw">mod</span> <span class="ident">print</span>;
<span class="kw">mod</span> <span class="ident">visitor</span>;
<span class="doccomment">/// An error that occurred while parsing a regular expression into an abstract</span>
<span class="doccomment">/// syntax tree.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that note all ASTs represents a valid regular expression. For example,</span>
<span class="doccomment">/// an AST is constructed without error for `\p{Quux}`, but `Quux` is not a</span>
<span class="doccomment">/// valid Unicode property name. That particular error is reported when</span>
<span class="doccomment">/// translating an AST to the high-level intermediate representation (`HIR`).</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Error</span> {
<span class="doccomment">/// The kind of error.</span>
<span class="ident">kind</span>: <span class="ident">ErrorKind</span>,
<span class="doccomment">/// The original pattern that the parser generated the error from. Every</span>
<span class="doccomment">/// span in an error is a valid range into this string.</span>
<span class="ident">pattern</span>: <span class="ident">String</span>,
<span class="doccomment">/// The span of this error.</span>
<span class="ident">span</span>: <span class="ident">Span</span>,
}
<span class="kw">impl</span> <span class="ident">Error</span> {
<span class="doccomment">/// Return the type of this error.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">kind</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">ErrorKind</span> {
<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">kind</span>
}
<span class="doccomment">/// The original pattern string in which this error occurred.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Every span reported by this error is reported in terms of this string.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">pattern</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">str</span> {
<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">pattern</span>
}
<span class="doccomment">/// Return the span at which this error occurred.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">span</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">Span</span> {
<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">span</span>
}
<span class="doccomment">/// Return an auxiliary span. This span exists only for some errors that</span>
<span class="doccomment">/// benefit from being able to point to two locations in the original</span>
<span class="doccomment">/// regular expression. For example, "duplicate" errors will have the</span>
<span class="doccomment">/// main error position set to the duplicate occurrence while its</span>
<span class="doccomment">/// auxiliary span will be set to the initial occurrence.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">auxiliary_span</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Span</span><span class="op">></span> {
<span class="kw">use</span> <span class="self">self</span>::<span class="ident">ErrorKind</span>::<span class="kw-2">*</span>;
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">kind</span> {
<span class="ident">FlagDuplicate</span> { <span class="kw-2">ref</span> <span class="ident">original</span> } <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">original</span>),
<span class="ident">FlagRepeatedNegation</span> { <span class="kw-2">ref</span> <span class="ident">original</span>, .. } <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">original</span>),
<span class="ident">GroupNameDuplicate</span> { <span class="kw-2">ref</span> <span class="ident">original</span>, .. } <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">original</span>),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">None</span>,
}
}
}
<span class="doccomment">/// The type of an error that occurred while building an AST.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ErrorKind</span> {
<span class="doccomment">/// The capturing group limit was exceeded.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that this represents a limit on the total number of capturing</span>
<span class="doccomment">/// groups in a regex and not necessarily the number of nested capturing</span>
<span class="doccomment">/// groups. That is, the nest limit can be low and it is still possible for</span>
<span class="doccomment">/// this error to occur.</span>
<span class="ident">CaptureLimitExceeded</span>,
<span class="doccomment">/// An invalid escape sequence was found in a character class set.</span>
<span class="ident">ClassEscapeInvalid</span>,
<span class="doccomment">/// An invalid character class range was found. An invalid range is any</span>
<span class="doccomment">/// range where the start is greater than the end.</span>
<span class="ident">ClassRangeInvalid</span>,
<span class="doccomment">/// An invalid range boundary was found in a character class. Range</span>
<span class="doccomment">/// boundaries must be a single literal codepoint, but this error indicates</span>
<span class="doccomment">/// that something else was found, such as a nested class.</span>
<span class="ident">ClassRangeLiteral</span>,
<span class="doccomment">/// An opening `[` was found with no corresponding closing `]`.</span>
<span class="ident">ClassUnclosed</span>,
<span class="doccomment">/// Note that this error variant is no longer used. Namely, a decimal</span>
<span class="doccomment">/// number can only appear as a repetition quantifier. When the number</span>
<span class="doccomment">/// in a repetition quantifier is empty, then it gets its own specialized</span>
<span class="doccomment">/// error, `RepetitionCountDecimalEmpty`.</span>
<span class="ident">DecimalEmpty</span>,
<span class="doccomment">/// An invalid decimal number was given where one was expected.</span>
<span class="ident">DecimalInvalid</span>,
<span class="doccomment">/// A bracketed hex literal was empty.</span>
<span class="ident">EscapeHexEmpty</span>,
<span class="doccomment">/// A bracketed hex literal did not correspond to a Unicode scalar value.</span>
<span class="ident">EscapeHexInvalid</span>,
<span class="doccomment">/// An invalid hexadecimal digit was found.</span>
<span class="ident">EscapeHexInvalidDigit</span>,
<span class="doccomment">/// EOF was found before an escape sequence was completed.</span>
<span class="ident">EscapeUnexpectedEof</span>,
<span class="doccomment">/// An unrecognized escape sequence.</span>
<span class="ident">EscapeUnrecognized</span>,
<span class="doccomment">/// A dangling negation was used when setting flags, e.g., `i-`.</span>
<span class="ident">FlagDanglingNegation</span>,
<span class="doccomment">/// A flag was used twice, e.g., `i-i`.</span>
<span class="ident">FlagDuplicate</span> {
<span class="doccomment">/// The position of the original flag. The error position</span>
<span class="doccomment">/// points to the duplicate flag.</span>
<span class="ident">original</span>: <span class="ident">Span</span>,
},
<span class="doccomment">/// The negation operator was used twice, e.g., `-i-s`.</span>
<span class="ident">FlagRepeatedNegation</span> {
<span class="doccomment">/// The position of the original negation operator. The error position</span>
<span class="doccomment">/// points to the duplicate negation operator.</span>
<span class="ident">original</span>: <span class="ident">Span</span>,
},
<span class="doccomment">/// Expected a flag but got EOF, e.g., `(?`.</span>
<span class="ident">FlagUnexpectedEof</span>,
<span class="doccomment">/// Unrecognized flag, e.g., `a`.</span>
<span class="ident">FlagUnrecognized</span>,
<span class="doccomment">/// A duplicate capture name was found.</span>
<span class="ident">GroupNameDuplicate</span> {
<span class="doccomment">/// The position of the initial occurrence of the capture name. The</span>
<span class="doccomment">/// error position itself points to the duplicate occurrence.</span>
<span class="ident">original</span>: <span class="ident">Span</span>,
},
<span class="doccomment">/// A capture group name is empty, e.g., `(?P<>abc)`.</span>
<span class="ident">GroupNameEmpty</span>,
<span class="doccomment">/// An invalid character was seen for a capture group name. This includes</span>
<span class="doccomment">/// errors where the first character is a digit (even though subsequent</span>
<span class="doccomment">/// characters are allowed to be digits).</span>
<span class="ident">GroupNameInvalid</span>,
<span class="doccomment">/// A closing `>` could not be found for a capture group name.</span>
<span class="ident">GroupNameUnexpectedEof</span>,
<span class="doccomment">/// An unclosed group, e.g., `(ab`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The span of this error corresponds to the unclosed parenthesis.</span>
<span class="ident">GroupUnclosed</span>,
<span class="doccomment">/// An unopened group, e.g., `ab)`.</span>
<span class="ident">GroupUnopened</span>,
<span class="doccomment">/// The nest limit was exceeded. The limit stored here is the limit</span>
<span class="doccomment">/// configured in the parser.</span>
<span class="ident">NestLimitExceeded</span>(<span class="ident">u32</span>),
<span class="doccomment">/// The range provided in a counted repetition operator is invalid. The</span>
<span class="doccomment">/// range is invalid if the start is greater than the end.</span>
<span class="ident">RepetitionCountInvalid</span>,
<span class="doccomment">/// An opening `{` was not followed by a valid decimal value.</span>
<span class="doccomment">/// For example, `x{}` or `x{]}` would fail.</span>
<span class="ident">RepetitionCountDecimalEmpty</span>,
<span class="doccomment">/// An opening `{` was found with no corresponding closing `}`.</span>
<span class="ident">RepetitionCountUnclosed</span>,
<span class="doccomment">/// A repetition operator was applied to a missing sub-expression. This</span>
<span class="doccomment">/// occurs, for example, in the regex consisting of just a `*` or even</span>
<span class="doccomment">/// `(?i)*`. It is, however, possible to create a repetition operating on</span>
<span class="doccomment">/// an empty sub-expression. For example, `()*` is still considered valid.</span>
<span class="ident">RepetitionMissing</span>,
<span class="doccomment">/// When octal support is disabled, this error is produced when an octal</span>
<span class="doccomment">/// escape is used. The octal escape is assumed to be an invocation of</span>
<span class="doccomment">/// a backreference, which is the common case.</span>
<span class="ident">UnsupportedBackreference</span>,
<span class="doccomment">/// When syntax similar to PCRE's look-around is used, this error is</span>
<span class="doccomment">/// returned. Some example syntaxes that are rejected include, but are</span>
<span class="doccomment">/// not necessarily limited to, `(?=re)`, `(?!re)`, `(?<=re)` and</span>
<span class="doccomment">/// `(?<!re)`. Note that all of these syntaxes are otherwise invalid; this</span>
<span class="doccomment">/// error is used to improve the user experience.</span>
<span class="ident">UnsupportedLookAround</span>,
<span class="doccomment">/// Hints that destructuring should not be exhaustive.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This enum may grow additional variants, so this makes sure clients</span>
<span class="doccomment">/// don't count on exhaustive matching. (Otherwise, adding a new variant</span>
<span class="doccomment">/// could break existing code.)</span>
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="ident">__Nonexhaustive</span>,
}
<span class="kw">impl</span> <span class="ident">error</span>::<span class="ident">Error</span> <span class="kw">for</span> <span class="ident">Error</span> {
<span class="kw">fn</span> <span class="ident">description</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">str</span> {
<span class="kw">use</span> <span class="self">self</span>::<span class="ident">ErrorKind</span>::<span class="kw-2">*</span>;
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">kind</span> {
<span class="ident">CaptureLimitExceeded</span> <span class="op">=</span><span class="op">></span> <span class="string">"capture group limit exceeded"</span>,
<span class="ident">ClassEscapeInvalid</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid escape sequence in character class"</span>,
<span class="ident">ClassRangeInvalid</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid character class range"</span>,
<span class="ident">ClassRangeLiteral</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid range boundary, must be a literal"</span>,
<span class="ident">ClassUnclosed</span> <span class="op">=</span><span class="op">></span> <span class="string">"unclosed character class"</span>,
<span class="ident">DecimalEmpty</span> <span class="op">=</span><span class="op">></span> <span class="string">"empty decimal literal"</span>,
<span class="ident">DecimalInvalid</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid decimal literal"</span>,
<span class="ident">EscapeHexEmpty</span> <span class="op">=</span><span class="op">></span> <span class="string">"empty hexadecimal literal"</span>,
<span class="ident">EscapeHexInvalid</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid hexadecimal literal"</span>,
<span class="ident">EscapeHexInvalidDigit</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid hexadecimal digit"</span>,
<span class="ident">EscapeUnexpectedEof</span> <span class="op">=</span><span class="op">></span> <span class="string">"unexpected eof (escape sequence)"</span>,
<span class="ident">EscapeUnrecognized</span> <span class="op">=</span><span class="op">></span> <span class="string">"unrecognized escape sequence"</span>,
<span class="ident">FlagDanglingNegation</span> <span class="op">=</span><span class="op">></span> <span class="string">"dangling flag negation operator"</span>,
<span class="ident">FlagDuplicate</span> { .. } <span class="op">=</span><span class="op">></span> <span class="string">"duplicate flag"</span>,
<span class="ident">FlagRepeatedNegation</span> { .. } <span class="op">=</span><span class="op">></span> <span class="string">"repeated negation"</span>,
<span class="ident">FlagUnexpectedEof</span> <span class="op">=</span><span class="op">></span> <span class="string">"unexpected eof (flag)"</span>,
<span class="ident">FlagUnrecognized</span> <span class="op">=</span><span class="op">></span> <span class="string">"unrecognized flag"</span>,
<span class="ident">GroupNameDuplicate</span> { .. } <span class="op">=</span><span class="op">></span> <span class="string">"duplicate capture group name"</span>,
<span class="ident">GroupNameEmpty</span> <span class="op">=</span><span class="op">></span> <span class="string">"empty capture group name"</span>,
<span class="ident">GroupNameInvalid</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid capture group name"</span>,
<span class="ident">GroupNameUnexpectedEof</span> <span class="op">=</span><span class="op">></span> <span class="string">"unclosed capture group name"</span>,
<span class="ident">GroupUnclosed</span> <span class="op">=</span><span class="op">></span> <span class="string">"unclosed group"</span>,
<span class="ident">GroupUnopened</span> <span class="op">=</span><span class="op">></span> <span class="string">"unopened group"</span>,
<span class="ident">NestLimitExceeded</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="string">"nest limit exceeded"</span>,
<span class="ident">RepetitionCountInvalid</span> <span class="op">=</span><span class="op">></span> <span class="string">"invalid repetition count range"</span>,
<span class="ident">RepetitionCountUnclosed</span> <span class="op">=</span><span class="op">></span> <span class="string">"unclosed counted repetition"</span>,
<span class="ident">RepetitionMissing</span> <span class="op">=</span><span class="op">></span> <span class="string">"repetition operator missing expression"</span>,
<span class="ident">UnsupportedBackreference</span> <span class="op">=</span><span class="op">></span> <span class="string">"backreferences are not supported"</span>,
<span class="ident">UnsupportedLookAround</span> <span class="op">=</span><span class="op">></span> <span class="string">"look-around is not supported"</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="macro">unreachable</span><span class="macro">!</span>(),
}
}
}
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Display</span> <span class="kw">for</span> <span class="ident">Error</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
::<span class="ident">error</span>::<span class="ident">Formatter</span>::<span class="ident">from</span>(<span class="self">self</span>).<span class="ident">fmt</span>(<span class="ident">f</span>)
}
}
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Display</span> <span class="kw">for</span> <span class="ident">ErrorKind</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="kw">use</span> <span class="self">self</span>::<span class="ident">ErrorKind</span>::<span class="kw-2">*</span>;
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">CaptureLimitExceeded</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(
<span class="ident">f</span>,
<span class="string">"exceeded the maximum number of \
capturing groups ({})"</span>,
::<span class="ident">std</span>::<span class="ident">u32</span>::<span class="ident">MAX</span>
),
<span class="ident">ClassEscapeInvalid</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"invalid escape sequence found in character class"</span>)
}
<span class="ident">ClassRangeInvalid</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(
<span class="ident">f</span>,
<span class="string">"invalid character class range, \
the start must be <= the end"</span>
),
<span class="ident">ClassRangeLiteral</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"invalid range boundary, must be a literal"</span>)
}
<span class="ident">ClassUnclosed</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"unclosed character class"</span>),
<span class="ident">DecimalEmpty</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"decimal literal empty"</span>),
<span class="ident">DecimalInvalid</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"decimal literal invalid"</span>),
<span class="ident">EscapeHexEmpty</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"hexadecimal literal empty"</span>),
<span class="ident">EscapeHexInvalid</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"hexadecimal literal is not a Unicode scalar value"</span>)
}
<span class="ident">EscapeHexInvalidDigit</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"invalid hexadecimal digit"</span>),
<span class="ident">EscapeUnexpectedEof</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(
<span class="ident">f</span>,
<span class="string">"incomplete escape sequence, \
reached end of pattern prematurely"</span>
),
<span class="ident">EscapeUnrecognized</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"unrecognized escape sequence"</span>),
<span class="ident">FlagDanglingNegation</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"dangling flag negation operator"</span>)
}
<span class="ident">FlagDuplicate</span> { .. } <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"duplicate flag"</span>),
<span class="ident">FlagRepeatedNegation</span> { .. } <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"flag negation operator repeated"</span>)
}
<span class="ident">FlagUnexpectedEof</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"expected flag but got end of regex"</span>)
}
<span class="ident">FlagUnrecognized</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"unrecognized flag"</span>),
<span class="ident">GroupNameDuplicate</span> { .. } <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"duplicate capture group name"</span>)
}
<span class="ident">GroupNameEmpty</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"empty capture group name"</span>),
<span class="ident">GroupNameInvalid</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"invalid capture group character"</span>),
<span class="ident">GroupNameUnexpectedEof</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"unclosed capture group name"</span>),
<span class="ident">GroupUnclosed</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"unclosed group"</span>),
<span class="ident">GroupUnopened</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"unopened group"</span>),
<span class="ident">NestLimitExceeded</span>(<span class="ident">limit</span>) <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(
<span class="ident">f</span>,
<span class="string">"exceed the maximum number of \
nested parentheses/brackets ({})"</span>,
<span class="ident">limit</span>
),
<span class="ident">RepetitionCountInvalid</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(
<span class="ident">f</span>,
<span class="string">"invalid repetition count range, \
the start must be <= the end"</span>
),
<span class="ident">RepetitionCountDecimalEmpty</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"repetition quantifier expects a valid decimal"</span>)
}
<span class="ident">RepetitionCountUnclosed</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"unclosed counted repetition"</span>)
}
<span class="ident">RepetitionMissing</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"repetition operator missing expression"</span>)
}
<span class="ident">UnsupportedBackreference</span> <span class="op">=</span><span class="op">></span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"backreferences are not supported"</span>)
}
<span class="ident">UnsupportedLookAround</span> <span class="op">=</span><span class="op">></span> <span class="macro">write</span><span class="macro">!</span>(
<span class="ident">f</span>,
<span class="string">"look-around, including look-ahead and look-behind, \
is not supported"</span>
),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="macro">unreachable</span><span class="macro">!</span>(),
}
}
}
<span class="doccomment">/// Span represents the position information of a single AST item.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// All span positions are absolute byte offsets that can be used on the</span>
<span class="doccomment">/// original regular expression that was parsed.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Span</span> {
<span class="doccomment">/// The start byte offset.</span>
<span class="kw">pub</span> <span class="ident">start</span>: <span class="ident">Position</span>,
<span class="doccomment">/// The end byte offset.</span>
<span class="kw">pub</span> <span class="ident">end</span>: <span class="ident">Position</span>,
}
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Span</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"Span({:?}, {:?})"</span>, <span class="self">self</span>.<span class="ident">start</span>, <span class="self">self</span>.<span class="ident">end</span>)
}
}
<span class="kw">impl</span> <span class="ident">Ord</span> <span class="kw">for</span> <span class="ident">Span</span> {
<span class="kw">fn</span> <span class="ident">cmp</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="ident">Span</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Ordering</span> {
(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">start</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">end</span>).<span class="ident">cmp</span>(<span class="kw-2">&</span>(<span class="kw-2">&</span><span class="ident">other</span>.<span class="ident">start</span>, <span class="kw-2">&</span><span class="ident">other</span>.<span class="ident">end</span>))
}
}
<span class="kw">impl</span> <span class="ident">PartialOrd</span> <span class="kw">for</span> <span class="ident">Span</span> {
<span class="kw">fn</span> <span class="ident">partial_cmp</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="ident">Span</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">Ordering</span><span class="op">></span> {
<span class="prelude-val">Some</span>(<span class="self">self</span>.<span class="ident">cmp</span>(<span class="ident">other</span>))
}
}
<span class="doccomment">/// A single position in a regular expression.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A position encodes one half of a span, and include the byte offset, line</span>
<span class="doccomment">/// number and column number.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Position</span> {
<span class="doccomment">/// The absolute offset of this position, starting at `0` from the</span>
<span class="doccomment">/// beginning of the regular expression pattern string.</span>
<span class="kw">pub</span> <span class="ident">offset</span>: <span class="ident">usize</span>,
<span class="doccomment">/// The line number, starting at `1`.</span>
<span class="kw">pub</span> <span class="ident">line</span>: <span class="ident">usize</span>,
<span class="doccomment">/// The approximate column number, starting at `1`.</span>
<span class="kw">pub</span> <span class="ident">column</span>: <span class="ident">usize</span>,
}
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Position</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="macro">write</span><span class="macro">!</span>(
<span class="ident">f</span>,
<span class="string">"Position(o: {:?}, l: {:?}, c: {:?})"</span>,
<span class="self">self</span>.<span class="ident">offset</span>, <span class="self">self</span>.<span class="ident">line</span>, <span class="self">self</span>.<span class="ident">column</span>
)
}
}
<span class="kw">impl</span> <span class="ident">Ord</span> <span class="kw">for</span> <span class="ident">Position</span> {
<span class="kw">fn</span> <span class="ident">cmp</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="ident">Position</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Ordering</span> {
<span class="self">self</span>.<span class="ident">offset</span>.<span class="ident">cmp</span>(<span class="kw-2">&</span><span class="ident">other</span>.<span class="ident">offset</span>)
}
}
<span class="kw">impl</span> <span class="ident">PartialOrd</span> <span class="kw">for</span> <span class="ident">Position</span> {
<span class="kw">fn</span> <span class="ident">partial_cmp</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">other</span>: <span class="kw-2">&</span><span class="ident">Position</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">Ordering</span><span class="op">></span> {
<span class="prelude-val">Some</span>(<span class="self">self</span>.<span class="ident">cmp</span>(<span class="ident">other</span>))
}
}
<span class="kw">impl</span> <span class="ident">Span</span> {
<span class="doccomment">/// Create a new span with the given positions.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">start</span>: <span class="ident">Position</span>, <span class="ident">end</span>: <span class="ident">Position</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Span</span> {
<span class="ident">Span</span> { <span class="ident">start</span>: <span class="ident">start</span>, <span class="ident">end</span>: <span class="ident">end</span> }
}
<span class="doccomment">/// Create a new span using the given position as the start and end.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">splat</span>(<span class="ident">pos</span>: <span class="ident">Position</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Span</span> {
<span class="ident">Span</span>::<span class="ident">new</span>(<span class="ident">pos</span>, <span class="ident">pos</span>)
}
<span class="doccomment">/// Create a new span by replacing the starting the position with the one</span>
<span class="doccomment">/// given.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">with_start</span>(<span class="self">self</span>, <span class="ident">pos</span>: <span class="ident">Position</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Span</span> {
<span class="ident">Span</span> { <span class="ident">start</span>: <span class="ident">pos</span>, ..<span class="self">self</span> }
}
<span class="doccomment">/// Create a new span by replacing the ending the position with the one</span>
<span class="doccomment">/// given.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">with_end</span>(<span class="self">self</span>, <span class="ident">pos</span>: <span class="ident">Position</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Span</span> {
<span class="ident">Span</span> { <span class="ident">end</span>: <span class="ident">pos</span>, ..<span class="self">self</span> }
}
<span class="doccomment">/// Returns true if and only if this span occurs on a single line.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_one_line</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="self">self</span>.<span class="ident">start</span>.<span class="ident">line</span> <span class="op">=</span><span class="op">=</span> <span class="self">self</span>.<span class="ident">end</span>.<span class="ident">line</span>
}
<span class="doccomment">/// Returns true if and only if this span is empty. That is, it points to</span>
<span class="doccomment">/// a single position in the concrete syntax of a regular expression.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="self">self</span>.<span class="ident">start</span>.<span class="ident">offset</span> <span class="op">=</span><span class="op">=</span> <span class="self">self</span>.<span class="ident">end</span>.<span class="ident">offset</span>
}
}
<span class="kw">impl</span> <span class="ident">Position</span> {
<span class="doccomment">/// Create a new position with the given information.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `offset` is the absolute offset of the position, starting at `0` from</span>
<span class="doccomment">/// the beginning of the regular expression pattern string.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `line` is the line number, starting at `1`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `column` is the approximate column number, starting at `1`.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">offset</span>: <span class="ident">usize</span>, <span class="ident">line</span>: <span class="ident">usize</span>, <span class="ident">column</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Position</span> {
<span class="ident">Position</span> { <span class="ident">offset</span>: <span class="ident">offset</span>, <span class="ident">line</span>: <span class="ident">line</span>, <span class="ident">column</span>: <span class="ident">column</span> }
}
}
<span class="doccomment">/// An abstract syntax tree for a singular expression along with comments</span>
<span class="doccomment">/// found.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Comments are not stored in the tree itself to avoid complexity. Each</span>
<span class="doccomment">/// comment contains a span of precisely where it occurred in the original</span>
<span class="doccomment">/// regular expression.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">WithComments</span> {
<span class="doccomment">/// The actual ast.</span>
<span class="kw">pub</span> <span class="ident">ast</span>: <span class="ident">Ast</span>,
<span class="doccomment">/// All comments found in the original regular expression.</span>
<span class="kw">pub</span> <span class="ident">comments</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">Comment</span><span class="op">></span>,
}
<span class="doccomment">/// A comment from a regular expression with an associated span.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A regular expression can only contain comments when the `x` flag is</span>
<span class="doccomment">/// enabled.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Comment</span> {
<span class="doccomment">/// The span of this comment, including the beginning `#` and ending `\n`.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The comment text, starting with the first character following the `#`</span>
<span class="doccomment">/// and ending with the last character preceding the `\n`.</span>
<span class="kw">pub</span> <span class="ident">comment</span>: <span class="ident">String</span>,
}
<span class="doccomment">/// An abstract syntax tree for a single regular expression.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// An `Ast`'s `fmt::Display` implementation uses constant stack space and heap</span>
<span class="doccomment">/// space proportional to the size of the `Ast`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This type defines its own destructor that uses constant stack space and</span>
<span class="doccomment">/// heap space proportional to the size of the `Ast`.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">Ast</span> {
<span class="doccomment">/// An empty regex that matches everything.</span>
<span class="ident">Empty</span>(<span class="ident">Span</span>),
<span class="doccomment">/// A set of flags, e.g., `(?is)`.</span>
<span class="ident">Flags</span>(<span class="ident">SetFlags</span>),
<span class="doccomment">/// A single character literal, which includes escape sequences.</span>
<span class="ident">Literal</span>(<span class="ident">Literal</span>),
<span class="doccomment">/// The "any character" class.</span>
<span class="ident">Dot</span>(<span class="ident">Span</span>),
<span class="doccomment">/// A single zero-width assertion.</span>
<span class="ident">Assertion</span>(<span class="ident">Assertion</span>),
<span class="doccomment">/// A single character class. This includes all forms of character classes</span>
<span class="doccomment">/// except for `.`. e.g., `\d`, `\pN`, `[a-z]` and `[[:alpha:]]`.</span>
<span class="ident">Class</span>(<span class="ident">Class</span>),
<span class="doccomment">/// A repetition operator applied to an arbitrary regular expression.</span>
<span class="ident">Repetition</span>(<span class="ident">Repetition</span>),
<span class="doccomment">/// A grouped regular expression.</span>
<span class="ident">Group</span>(<span class="ident">Group</span>),
<span class="doccomment">/// An alternation of regular expressions.</span>
<span class="ident">Alternation</span>(<span class="ident">Alternation</span>),
<span class="doccomment">/// A concatenation of regular expressions.</span>
<span class="ident">Concat</span>(<span class="ident">Concat</span>),
}
<span class="kw">impl</span> <span class="ident">Ast</span> {
<span class="doccomment">/// Return the span of this abstract syntax tree.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">span</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">Span</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="kw-2">ref</span> <span class="ident">span</span>) <span class="op">=</span><span class="op">></span> <span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Flags</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Literal</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Dot</span>(<span class="kw-2">ref</span> <span class="ident">span</span>) <span class="op">=</span><span class="op">></span> <span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Assertion</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Class</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="ident">x</span>.<span class="ident">span</span>(),
<span class="ident">Ast</span>::<span class="ident">Repetition</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Group</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Alternation</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Ast</span>::<span class="ident">Concat</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
}
}
<span class="doccomment">/// Return true if and only if this Ast is empty.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
<span class="doccomment">/// Returns true if and only if this AST has any (including possibly empty)</span>
<span class="doccomment">/// subexpressions.</span>
<span class="kw">fn</span> <span class="ident">has_subexprs</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Flags</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Literal</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Dot</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Assertion</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
<span class="ident">Ast</span>::<span class="ident">Class</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Repetition</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Group</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Alternation</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Concat</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
}
}
}
<span class="doccomment">/// Print a display representation of this Ast.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This does not preserve any of the original whitespace formatting that may</span>
<span class="doccomment">/// have originally been present in the concrete syntax from which this Ast</span>
<span class="doccomment">/// was generated.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This implementation uses constant stack space and heap space proportional</span>
<span class="doccomment">/// to the size of the `Ast`.</span>
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Display</span> <span class="kw">for</span> <span class="ident">Ast</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="kw">use</span> <span class="ident">ast</span>::<span class="ident">print</span>::<span class="ident">Printer</span>;
<span class="ident">Printer</span>::<span class="ident">new</span>().<span class="ident">print</span>(<span class="self">self</span>, <span class="ident">f</span>)
}
}
<span class="doccomment">/// An alternation of regular expressions.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Alternation</span> {
<span class="doccomment">/// The span of this alternation.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The alternate regular expressions.</span>
<span class="kw">pub</span> <span class="ident">asts</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">Ast</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">Alternation</span> {
<span class="doccomment">/// Return this alternation as an AST.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If this alternation contains zero ASTs, then Ast::Empty is</span>
<span class="doccomment">/// returned. If this alternation contains exactly 1 AST, then the</span>
<span class="doccomment">/// corresponding AST is returned. Otherwise, Ast::Alternation is returned.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_ast</span>(<span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Ast</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">asts</span>.<span class="ident">len</span>() {
<span class="number">0</span> <span class="op">=</span><span class="op">></span> <span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="self">self</span>.<span class="ident">span</span>),
<span class="number">1</span> <span class="op">=</span><span class="op">></span> <span class="self">self</span>.<span class="ident">asts</span>.<span class="ident">pop</span>().<span class="ident">unwrap</span>(),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="ident">Ast</span>::<span class="ident">Alternation</span>(<span class="self">self</span>),
}
}
}
<span class="doccomment">/// A concatenation of regular expressions.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Concat</span> {
<span class="doccomment">/// The span of this concatenation.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The concatenation regular expressions.</span>
<span class="kw">pub</span> <span class="ident">asts</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">Ast</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">Concat</span> {
<span class="doccomment">/// Return this concatenation as an AST.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If this concatenation contains zero ASTs, then Ast::Empty is</span>
<span class="doccomment">/// returned. If this concatenation contains exactly 1 AST, then the</span>
<span class="doccomment">/// corresponding AST is returned. Otherwise, Ast::Concat is returned.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_ast</span>(<span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Ast</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">asts</span>.<span class="ident">len</span>() {
<span class="number">0</span> <span class="op">=</span><span class="op">></span> <span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="self">self</span>.<span class="ident">span</span>),
<span class="number">1</span> <span class="op">=</span><span class="op">></span> <span class="self">self</span>.<span class="ident">asts</span>.<span class="ident">pop</span>().<span class="ident">unwrap</span>(),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="ident">Ast</span>::<span class="ident">Concat</span>(<span class="self">self</span>),
}
}
}
<span class="doccomment">/// A single literal expression.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A literal corresponds to a single Unicode scalar value. Literals may be</span>
<span class="doccomment">/// represented in their literal form, e.g., `a` or in their escaped form,</span>
<span class="doccomment">/// e.g., `\x61`.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Literal</span> {
<span class="doccomment">/// The span of this literal.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The kind of this literal.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">LiteralKind</span>,
<span class="doccomment">/// The Unicode scalar value corresponding to this literal.</span>
<span class="kw">pub</span> <span class="ident">c</span>: <span class="ident">char</span>,
}
<span class="kw">impl</span> <span class="ident">Literal</span> {
<span class="doccomment">/// If this literal was written as a `\x` hex escape, then this returns</span>
<span class="doccomment">/// the corresponding byte value. Otherwise, this returns `None`.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">byte</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">u8</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">short_hex</span> <span class="op">=</span> <span class="ident">LiteralKind</span>::<span class="ident">HexFixed</span>(<span class="ident">HexLiteralKind</span>::<span class="ident">X</span>);
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">c</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op"><</span><span class="op">=</span> <span class="number">255</span> <span class="kw-2">&</span><span class="op">&</span> <span class="self">self</span>.<span class="ident">kind</span> <span class="op">=</span><span class="op">=</span> <span class="ident">short_hex</span> {
<span class="prelude-val">Some</span>(<span class="self">self</span>.<span class="ident">c</span> <span class="kw">as</span> <span class="ident">u8</span>)
} <span class="kw">else</span> {
<span class="prelude-val">None</span>
}
}
}
<span class="doccomment">/// The kind of a single literal expression.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">LiteralKind</span> {
<span class="doccomment">/// The literal is written verbatim, e.g., `a` or `☃`.</span>
<span class="ident">Verbatim</span>,
<span class="doccomment">/// The literal is written as an escape because it is punctuation, e.g.,</span>
<span class="doccomment">/// `\*` or `\[`.</span>
<span class="ident">Punctuation</span>,
<span class="doccomment">/// The literal is written as an octal escape, e.g., `\141`.</span>
<span class="ident">Octal</span>,
<span class="doccomment">/// The literal is written as a hex code with a fixed number of digits</span>
<span class="doccomment">/// depending on the type of the escape, e.g., `\x61` or or `\u0061` or</span>
<span class="doccomment">/// `\U00000061`.</span>
<span class="ident">HexFixed</span>(<span class="ident">HexLiteralKind</span>),
<span class="doccomment">/// The literal is written as a hex code with a bracketed number of</span>
<span class="doccomment">/// digits. The only restriction is that the bracketed hex code must refer</span>
<span class="doccomment">/// to a valid Unicode scalar value.</span>
<span class="ident">HexBrace</span>(<span class="ident">HexLiteralKind</span>),
<span class="doccomment">/// The literal is written as a specially recognized escape, e.g., `\f`</span>
<span class="doccomment">/// or `\n`.</span>
<span class="ident">Special</span>(<span class="ident">SpecialLiteralKind</span>),
}
<span class="doccomment">/// The type of a special literal.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A special literal is a special escape sequence recognized by the regex</span>
<span class="doccomment">/// parser, e.g., `\f` or `\n`.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">SpecialLiteralKind</span> {
<span class="doccomment">/// Bell, spelled `\a` (`\x07`).</span>
<span class="ident">Bell</span>,
<span class="doccomment">/// Form feed, spelled `\f` (`\x0C`).</span>
<span class="ident">FormFeed</span>,
<span class="doccomment">/// Tab, spelled `\t` (`\x09`).</span>
<span class="ident">Tab</span>,
<span class="doccomment">/// Line feed, spelled `\n` (`\x0A`).</span>
<span class="ident">LineFeed</span>,
<span class="doccomment">/// Carriage return, spelled `\r` (`\x0D`).</span>
<span class="ident">CarriageReturn</span>,
<span class="doccomment">/// Vertical tab, spelled `\v` (`\x0B`).</span>
<span class="ident">VerticalTab</span>,
<span class="doccomment">/// Space, spelled `\ ` (`\x20`). Note that this can only appear when</span>
<span class="doccomment">/// parsing in verbose mode.</span>
<span class="ident">Space</span>,
}
<span class="doccomment">/// The type of a Unicode hex literal.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that all variants behave the same when used with brackets. They only</span>
<span class="doccomment">/// differ when used without brackets in the number of hex digits that must</span>
<span class="doccomment">/// follow.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">HexLiteralKind</span> {
<span class="doccomment">/// A `\x` prefix. When used without brackets, this form is limited to</span>
<span class="doccomment">/// two digits.</span>
<span class="ident">X</span>,
<span class="doccomment">/// A `\u` prefix. When used without brackets, this form is limited to</span>
<span class="doccomment">/// four digits.</span>
<span class="ident">UnicodeShort</span>,
<span class="doccomment">/// A `\U` prefix. When used without brackets, this form is limited to</span>
<span class="doccomment">/// eight digits.</span>
<span class="ident">UnicodeLong</span>,
}
<span class="kw">impl</span> <span class="ident">HexLiteralKind</span> {
<span class="doccomment">/// The number of digits that must be used with this literal form when</span>
<span class="doccomment">/// used without brackets. When used with brackets, there is no</span>
<span class="doccomment">/// restriction on the number of digits.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">digits</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">u32</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">HexLiteralKind</span>::<span class="ident">X</span> <span class="op">=</span><span class="op">></span> <span class="number">2</span>,
<span class="ident">HexLiteralKind</span>::<span class="ident">UnicodeShort</span> <span class="op">=</span><span class="op">></span> <span class="number">4</span>,
<span class="ident">HexLiteralKind</span>::<span class="ident">UnicodeLong</span> <span class="op">=</span><span class="op">></span> <span class="number">8</span>,
}
}
}
<span class="doccomment">/// A single character class expression.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">Class</span> {
<span class="doccomment">/// A Unicode character class, e.g., `\pL` or `\p{Greek}`.</span>
<span class="ident">Unicode</span>(<span class="ident">ClassUnicode</span>),
<span class="doccomment">/// A perl character class, e.g., `\d` or `\W`.</span>
<span class="ident">Perl</span>(<span class="ident">ClassPerl</span>),
<span class="doccomment">/// A bracketed character class set, which may contain zero or more</span>
<span class="doccomment">/// character ranges and/or zero or more nested classes. e.g.,</span>
<span class="doccomment">/// `[a-zA-Z\pL]`.</span>
<span class="ident">Bracketed</span>(<span class="ident">ClassBracketed</span>),
}
<span class="kw">impl</span> <span class="ident">Class</span> {
<span class="doccomment">/// Return the span of this character class.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">span</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">Span</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Class</span>::<span class="ident">Perl</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Class</span>::<span class="ident">Unicode</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">Class</span>::<span class="ident">Bracketed</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
}
}
}
<span class="doccomment">/// A Perl character class.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ClassPerl</span> {
<span class="doccomment">/// The span of this class.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The kind of Perl class.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">ClassPerlKind</span>,
<span class="doccomment">/// Whether the class is negated or not. e.g., `\d` is not negated but</span>
<span class="doccomment">/// `\D` is.</span>
<span class="kw">pub</span> <span class="ident">negated</span>: <span class="ident">bool</span>,
}
<span class="doccomment">/// The available Perl character classes.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ClassPerlKind</span> {
<span class="doccomment">/// Decimal numbers.</span>
<span class="ident">Digit</span>,
<span class="doccomment">/// Whitespace.</span>
<span class="ident">Space</span>,
<span class="doccomment">/// Word characters.</span>
<span class="ident">Word</span>,
}
<span class="doccomment">/// An ASCII character class.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ClassAscii</span> {
<span class="doccomment">/// The span of this class.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The kind of ASCII class.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">ClassAsciiKind</span>,
<span class="doccomment">/// Whether the class is negated or not. e.g., `[[:alpha:]]` is not negated</span>
<span class="doccomment">/// but `[[:^alpha:]]` is.</span>
<span class="kw">pub</span> <span class="ident">negated</span>: <span class="ident">bool</span>,
}
<span class="doccomment">/// The available ASCII character classes.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ClassAsciiKind</span> {
<span class="doccomment">/// `[0-9A-Za-z]`</span>
<span class="ident">Alnum</span>,
<span class="doccomment">/// `[A-Za-z]`</span>
<span class="ident">Alpha</span>,
<span class="doccomment">/// `[\x00-\x7F]`</span>
<span class="ident">Ascii</span>,
<span class="doccomment">/// `[ \t]`</span>
<span class="ident">Blank</span>,
<span class="doccomment">/// `[\x00-\x1F\x7F]`</span>
<span class="ident">Cntrl</span>,
<span class="doccomment">/// `[0-9]`</span>
<span class="ident">Digit</span>,
<span class="doccomment">/// `[!-~]`</span>
<span class="ident">Graph</span>,
<span class="doccomment">/// `[a-z]`</span>
<span class="ident">Lower</span>,
<span class="doccomment">/// `[ -~]`</span>
<span class="ident">Print</span>,
<span class="doccomment">/// `[!-/:-@\[-`{-~]`</span>
<span class="ident">Punct</span>,
<span class="doccomment">/// `[\t\n\v\f\r ]`</span>
<span class="ident">Space</span>,
<span class="doccomment">/// `[A-Z]`</span>
<span class="ident">Upper</span>,
<span class="doccomment">/// `[0-9A-Za-z_]`</span>
<span class="ident">Word</span>,
<span class="doccomment">/// `[0-9A-Fa-f]`</span>
<span class="ident">Xdigit</span>,
}
<span class="kw">impl</span> <span class="ident">ClassAsciiKind</span> {
<span class="doccomment">/// Return the corresponding ClassAsciiKind variant for the given name.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The name given should correspond to the lowercase version of the</span>
<span class="doccomment">/// variant name. e.g., `cntrl` is the name for `ClassAsciiKind::Cntrl`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If no variant with the corresponding name exists, then `None` is</span>
<span class="doccomment">/// returned.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">from_name</span>(<span class="ident">name</span>: <span class="kw-2">&</span><span class="ident">str</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">ClassAsciiKind</span><span class="op">></span> {
<span class="kw">use</span> <span class="self">self</span>::<span class="ident">ClassAsciiKind</span>::<span class="kw-2">*</span>;
<span class="kw">match</span> <span class="ident">name</span> {
<span class="string">"alnum"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Alnum</span>),
<span class="string">"alpha"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Alpha</span>),
<span class="string">"ascii"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Ascii</span>),
<span class="string">"blank"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Blank</span>),
<span class="string">"cntrl"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Cntrl</span>),
<span class="string">"digit"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Digit</span>),
<span class="string">"graph"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Graph</span>),
<span class="string">"lower"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Lower</span>),
<span class="string">"print"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Print</span>),
<span class="string">"punct"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Punct</span>),
<span class="string">"space"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Space</span>),
<span class="string">"upper"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Upper</span>),
<span class="string">"word"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Word</span>),
<span class="string">"xdigit"</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">Xdigit</span>),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">None</span>,
}
}
}
<span class="doccomment">/// A Unicode character class.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ClassUnicode</span> {
<span class="doccomment">/// The span of this class.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// Whether this class is negated or not.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note: be careful when using this attribute. This specifically refers</span>
<span class="doccomment">/// to whether the class is written as `\p` or `\P`, where the latter</span>
<span class="doccomment">/// is `negated = true`. However, it also possible to write something like</span>
<span class="doccomment">/// `\P{scx!=Katakana}` which is actually equivalent to</span>
<span class="doccomment">/// `\p{scx=Katakana}` and is therefore not actually negated even though</span>
<span class="doccomment">/// `negated = true` here. To test whether this class is truly negated</span>
<span class="doccomment">/// or not, use the `is_negated` method.</span>
<span class="kw">pub</span> <span class="ident">negated</span>: <span class="ident">bool</span>,
<span class="doccomment">/// The kind of Unicode class.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">ClassUnicodeKind</span>,
}
<span class="kw">impl</span> <span class="ident">ClassUnicode</span> {
<span class="doccomment">/// Returns true if this class has been negated.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that this takes the Unicode op into account, if it's present.</span>
<span class="doccomment">/// e.g., `is_negated` for `\P{scx!=Katakana}` will return `false`.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_negated</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">kind</span> {
<span class="ident">ClassUnicodeKind</span>::<span class="ident">NamedValue</span> {
<span class="ident">op</span>: <span class="ident">ClassUnicodeOpKind</span>::<span class="ident">NotEqual</span>,
..
} <span class="op">=</span><span class="op">></span> <span class="op">!</span><span class="self">self</span>.<span class="ident">negated</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="self">self</span>.<span class="ident">negated</span>,
}
}
}
<span class="doccomment">/// The available forms of Unicode character classes.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ClassUnicodeKind</span> {
<span class="doccomment">/// A one letter abbreviated class, e.g., `\pN`.</span>
<span class="ident">OneLetter</span>(<span class="ident">char</span>),
<span class="doccomment">/// A binary property, general category or script. The string may be</span>
<span class="doccomment">/// empty.</span>
<span class="ident">Named</span>(<span class="ident">String</span>),
<span class="doccomment">/// A property name and an associated value.</span>
<span class="ident">NamedValue</span> {
<span class="doccomment">/// The type of Unicode op used to associate `name` with `value`.</span>
<span class="ident">op</span>: <span class="ident">ClassUnicodeOpKind</span>,
<span class="doccomment">/// The property name (which may be empty).</span>
<span class="ident">name</span>: <span class="ident">String</span>,
<span class="doccomment">/// The property value (which may be empty).</span>
<span class="ident">value</span>: <span class="ident">String</span>,
},
}
<span class="doccomment">/// The type of op used in a Unicode character class.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ClassUnicodeOpKind</span> {
<span class="doccomment">/// A property set to a specific value, e.g., `\p{scx=Katakana}`.</span>
<span class="ident">Equal</span>,
<span class="doccomment">/// A property set to a specific value using a colon, e.g.,</span>
<span class="doccomment">/// `\p{scx:Katakana}`.</span>
<span class="ident">Colon</span>,
<span class="doccomment">/// A property that isn't a particular value, e.g., `\p{scx!=Katakana}`.</span>
<span class="ident">NotEqual</span>,
}
<span class="kw">impl</span> <span class="ident">ClassUnicodeOpKind</span> {
<span class="doccomment">/// Whether the op is an equality op or not.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_equal</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">ClassUnicodeOpKind</span>::<span class="ident">Equal</span> <span class="op">|</span> <span class="ident">ClassUnicodeOpKind</span>::<span class="ident">Colon</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
}
<span class="doccomment">/// A bracketed character class, e.g., `[a-z0-9]`.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ClassBracketed</span> {
<span class="doccomment">/// The span of this class.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// Whether this class is negated or not. e.g., `[a]` is not negated but</span>
<span class="doccomment">/// `[^a]` is.</span>
<span class="kw">pub</span> <span class="ident">negated</span>: <span class="ident">bool</span>,
<span class="doccomment">/// The type of this set. A set is either a normal union of things, e.g.,</span>
<span class="doccomment">/// `[abc]` or a result of applying set operations, e.g., `[\pL--c]`.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">ClassSet</span>,
}
<span class="doccomment">/// A character class set.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This type corresponds to the internal structure of a bracketed character</span>
<span class="doccomment">/// class. That is, every bracketed character is one of two types: a union of</span>
<span class="doccomment">/// items (literals, ranges, other bracketed classes) or a tree of binary set</span>
<span class="doccomment">/// operations.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ClassSet</span> {
<span class="doccomment">/// An item, which can be a single literal, range, nested character class</span>
<span class="doccomment">/// or a union of items.</span>
<span class="ident">Item</span>(<span class="ident">ClassSetItem</span>),
<span class="doccomment">/// A single binary operation (i.e., &&, -- or ~~).</span>
<span class="ident">BinaryOp</span>(<span class="ident">ClassSetBinaryOp</span>),
}
<span class="kw">impl</span> <span class="ident">ClassSet</span> {
<span class="doccomment">/// Build a set from a union.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">union</span>(<span class="ident">ast</span>: <span class="ident">ClassSetUnion</span>) <span class="op">-</span><span class="op">></span> <span class="ident">ClassSet</span> {
<span class="ident">ClassSet</span>::<span class="ident">Item</span>(<span class="ident">ClassSetItem</span>::<span class="ident">Union</span>(<span class="ident">ast</span>))
}
<span class="doccomment">/// Return the span of this character class set.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">span</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">Span</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">ClassSet</span>::<span class="ident">Item</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="ident">x</span>.<span class="ident">span</span>(),
<span class="ident">ClassSet</span>::<span class="ident">BinaryOp</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
}
}
<span class="doccomment">/// Return true if and only if this class set is empty.</span>
<span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">ClassSet</span>::<span class="ident">Item</span>(<span class="ident">ClassSetItem</span>::<span class="ident">Empty</span>(<span class="kw">_</span>)) <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
}
<span class="doccomment">/// A single component of a character class set.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ClassSetItem</span> {
<span class="doccomment">/// An empty item.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that a bracketed character class cannot contain a single empty</span>
<span class="doccomment">/// item. Empty items can appear when using one of the binary operators.</span>
<span class="doccomment">/// For example, `[&&]` is the intersection of two empty classes.</span>
<span class="ident">Empty</span>(<span class="ident">Span</span>),
<span class="doccomment">/// A single literal.</span>
<span class="ident">Literal</span>(<span class="ident">Literal</span>),
<span class="doccomment">/// A range between two literals.</span>
<span class="ident">Range</span>(<span class="ident">ClassSetRange</span>),
<span class="doccomment">/// An ASCII character class, e.g., `[:alnum:]` or `[:punct:]`.</span>
<span class="ident">Ascii</span>(<span class="ident">ClassAscii</span>),
<span class="doccomment">/// A Unicode character class, e.g., `\pL` or `\p{Greek}`.</span>
<span class="ident">Unicode</span>(<span class="ident">ClassUnicode</span>),
<span class="doccomment">/// A perl character class, e.g., `\d` or `\W`.</span>
<span class="ident">Perl</span>(<span class="ident">ClassPerl</span>),
<span class="doccomment">/// A bracketed character class set, which may contain zero or more</span>
<span class="doccomment">/// character ranges and/or zero or more nested classes. e.g.,</span>
<span class="doccomment">/// `[a-zA-Z\pL]`.</span>
<span class="ident">Bracketed</span>(<span class="ident">Box</span><span class="op"><</span><span class="ident">ClassBracketed</span><span class="op">></span>),
<span class="doccomment">/// A union of items.</span>
<span class="ident">Union</span>(<span class="ident">ClassSetUnion</span>),
}
<span class="kw">impl</span> <span class="ident">ClassSetItem</span> {
<span class="doccomment">/// Return the span of this character class set item.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">span</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">Span</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">ClassSetItem</span>::<span class="ident">Empty</span>(<span class="kw-2">ref</span> <span class="ident">span</span>) <span class="op">=</span><span class="op">></span> <span class="ident">span</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Literal</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Range</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Ascii</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Perl</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Unicode</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Bracketed</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Union</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">x</span>.<span class="ident">span</span>,
}
}
}
<span class="doccomment">/// A single character class range in a set.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ClassSetRange</span> {
<span class="doccomment">/// The span of this range.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The start of this range.</span>
<span class="kw">pub</span> <span class="ident">start</span>: <span class="ident">Literal</span>,
<span class="doccomment">/// The end of this range.</span>
<span class="kw">pub</span> <span class="ident">end</span>: <span class="ident">Literal</span>,
}
<span class="kw">impl</span> <span class="ident">ClassSetRange</span> {
<span class="doccomment">/// Returns true if and only if this character class range is valid.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The only case where a range is invalid is if its start is greater than</span>
<span class="doccomment">/// its end.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_valid</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="self">self</span>.<span class="ident">start</span>.<span class="ident">c</span> <span class="op"><</span><span class="op">=</span> <span class="self">self</span>.<span class="ident">end</span>.<span class="ident">c</span>
}
}
<span class="doccomment">/// A union of items inside a character class set.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ClassSetUnion</span> {
<span class="doccomment">/// The span of the items in this operation. e.g., the `a-z0-9` in</span>
<span class="doccomment">/// `[^a-z0-9]`</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The sequence of items that make up this union.</span>
<span class="kw">pub</span> <span class="ident">items</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">ClassSetItem</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">ClassSetUnion</span> {
<span class="doccomment">/// Push a new item in this union.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The ending position of this union's span is updated to the ending</span>
<span class="doccomment">/// position of the span of the item given. If the union is empty, then</span>
<span class="doccomment">/// the starting position of this union is set to the starting position</span>
<span class="doccomment">/// of this item.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// In other words, if you only use this method to add items to a union</span>
<span class="doccomment">/// and you set the spans on each item correctly, then you should never</span>
<span class="doccomment">/// need to adjust the span of the union directly.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">push</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">item</span>: <span class="ident">ClassSetItem</span>) {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">items</span>.<span class="ident">is_empty</span>() {
<span class="self">self</span>.<span class="ident">span</span>.<span class="ident">start</span> <span class="op">=</span> <span class="ident">item</span>.<span class="ident">span</span>().<span class="ident">start</span>;
}
<span class="self">self</span>.<span class="ident">span</span>.<span class="ident">end</span> <span class="op">=</span> <span class="ident">item</span>.<span class="ident">span</span>().<span class="ident">end</span>;
<span class="self">self</span>.<span class="ident">items</span>.<span class="ident">push</span>(<span class="ident">item</span>);
}
<span class="doccomment">/// Return this union as a character class set item.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If this union contains zero items, then an empty union is</span>
<span class="doccomment">/// returned. If this concatenation contains exactly 1 item, then the</span>
<span class="doccomment">/// corresponding item is returned. Otherwise, ClassSetItem::Union is</span>
<span class="doccomment">/// returned.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_item</span>(<span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">ClassSetItem</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">items</span>.<span class="ident">len</span>() {
<span class="number">0</span> <span class="op">=</span><span class="op">></span> <span class="ident">ClassSetItem</span>::<span class="ident">Empty</span>(<span class="self">self</span>.<span class="ident">span</span>),
<span class="number">1</span> <span class="op">=</span><span class="op">></span> <span class="self">self</span>.<span class="ident">items</span>.<span class="ident">pop</span>().<span class="ident">unwrap</span>(),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="ident">ClassSetItem</span>::<span class="ident">Union</span>(<span class="self">self</span>),
}
}
}
<span class="doccomment">/// A Unicode character class set operation.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ClassSetBinaryOp</span> {
<span class="doccomment">/// The span of this operation. e.g., the `a-z--[h-p]` in `[a-z--h-p]`.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The type of this set operation.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">ClassSetBinaryOpKind</span>,
<span class="doccomment">/// The left hand side of the operation.</span>
<span class="kw">pub</span> <span class="ident">lhs</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">ClassSet</span><span class="op">></span>,
<span class="doccomment">/// The right hand side of the operation.</span>
<span class="kw">pub</span> <span class="ident">rhs</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">ClassSet</span><span class="op">></span>,
}
<span class="doccomment">/// The type of a Unicode character class set operation.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that this doesn't explicitly represent union since there is no</span>
<span class="doccomment">/// explicit union operator. Concatenation inside a character class corresponds</span>
<span class="doccomment">/// to the union operation.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ClassSetBinaryOpKind</span> {
<span class="doccomment">/// The intersection of two sets, e.g., `\pN&&[a-z]`.</span>
<span class="ident">Intersection</span>,
<span class="doccomment">/// The difference of two sets, e.g., `\pN--[0-9]`.</span>
<span class="ident">Difference</span>,
<span class="doccomment">/// The symmetric difference of two sets. The symmetric difference is the</span>
<span class="doccomment">/// set of elements belonging to one but not both sets.</span>
<span class="doccomment">/// e.g., `[\pL~~[:ascii:]]`.</span>
<span class="ident">SymmetricDifference</span>,
}
<span class="doccomment">/// A single zero-width assertion.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Assertion</span> {
<span class="doccomment">/// The span of this assertion.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The assertion kind, e.g., `\b` or `^`.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">AssertionKind</span>,
}
<span class="doccomment">/// An assertion kind.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">AssertionKind</span> {
<span class="doccomment">/// `^`</span>
<span class="ident">StartLine</span>,
<span class="doccomment">/// `$`</span>
<span class="ident">EndLine</span>,
<span class="doccomment">/// `\A`</span>
<span class="ident">StartText</span>,
<span class="doccomment">/// `\z`</span>
<span class="ident">EndText</span>,
<span class="doccomment">/// `\b`</span>
<span class="ident">WordBoundary</span>,
<span class="doccomment">/// `\B`</span>
<span class="ident">NotWordBoundary</span>,
}
<span class="doccomment">/// A repetition operation applied to a regular expression.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Repetition</span> {
<span class="doccomment">/// The span of this operation.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The actual operation.</span>
<span class="kw">pub</span> <span class="ident">op</span>: <span class="ident">RepetitionOp</span>,
<span class="doccomment">/// Whether this operation was applied greedily or not.</span>
<span class="kw">pub</span> <span class="ident">greedy</span>: <span class="ident">bool</span>,
<span class="doccomment">/// The regular expression under repetition.</span>
<span class="kw">pub</span> <span class="ident">ast</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">Ast</span><span class="op">></span>,
}
<span class="doccomment">/// The repetition operator itself.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">RepetitionOp</span> {
<span class="doccomment">/// The span of this operator. This includes things like `+`, `*?` and</span>
<span class="doccomment">/// `{m,n}`.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The type of operation.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">RepetitionKind</span>,
}
<span class="doccomment">/// The kind of a repetition operator.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">RepetitionKind</span> {
<span class="doccomment">/// `?`</span>
<span class="ident">ZeroOrOne</span>,
<span class="doccomment">/// `*`</span>
<span class="ident">ZeroOrMore</span>,
<span class="doccomment">/// `+`</span>
<span class="ident">OneOrMore</span>,
<span class="doccomment">/// `{m,n}`</span>
<span class="ident">Range</span>(<span class="ident">RepetitionRange</span>),
}
<span class="doccomment">/// A range repetition operator.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">RepetitionRange</span> {
<span class="doccomment">/// `{m}`</span>
<span class="ident">Exactly</span>(<span class="ident">u32</span>),
<span class="doccomment">/// `{m,}`</span>
<span class="ident">AtLeast</span>(<span class="ident">u32</span>),
<span class="doccomment">/// `{m,n}`</span>
<span class="ident">Bounded</span>(<span class="ident">u32</span>, <span class="ident">u32</span>),
}
<span class="kw">impl</span> <span class="ident">RepetitionRange</span> {
<span class="doccomment">/// Returns true if and only if this repetition range is valid.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The only case where a repetition range is invalid is if it is bounded</span>
<span class="doccomment">/// and its start is greater than its end.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_valid</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">RepetitionRange</span>::<span class="ident">Bounded</span>(<span class="ident">s</span>, <span class="ident">e</span>) <span class="kw">if</span> <span class="ident">s</span> <span class="op">></span> <span class="ident">e</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
}
}
}
<span class="doccomment">/// A grouped regular expression.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This includes both capturing and non-capturing groups. This does **not**</span>
<span class="doccomment">/// include flag-only groups like `(?is)`, but does contain any group that</span>
<span class="doccomment">/// contains a sub-expression, e.g., `(a)`, `(?P<name>a)`, `(?:a)` and</span>
<span class="doccomment">/// `(?is:a)`.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Group</span> {
<span class="doccomment">/// The span of this group.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The kind of this group.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">GroupKind</span>,
<span class="doccomment">/// The regular expression in this group.</span>
<span class="kw">pub</span> <span class="ident">ast</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">Ast</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">Group</span> {
<span class="doccomment">/// If this group is non-capturing, then this returns the (possibly empty)</span>
<span class="doccomment">/// set of flags. Otherwise, `None` is returned.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">flags</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Flags</span><span class="op">></span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">kind</span> {
<span class="ident">GroupKind</span>::<span class="ident">NonCapturing</span>(<span class="kw-2">ref</span> <span class="ident">flags</span>) <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">flags</span>),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">None</span>,
}
}
<span class="doccomment">/// Returns true if and only if this group is capturing.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_capturing</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">kind</span> {
<span class="ident">GroupKind</span>::<span class="ident">CaptureIndex</span>(<span class="kw">_</span>) <span class="op">|</span> <span class="ident">GroupKind</span>::<span class="ident">CaptureName</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="ident">GroupKind</span>::<span class="ident">NonCapturing</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
<span class="doccomment">/// Returns the capture index of this group, if this is a capturing group.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This returns a capture index precisely when `is_capturing` is `true`.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">capture_index</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">u32</span><span class="op">></span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">kind</span> {
<span class="ident">GroupKind</span>::<span class="ident">CaptureIndex</span>(<span class="ident">i</span>) <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">i</span>),
<span class="ident">GroupKind</span>::<span class="ident">CaptureName</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">x</span>.<span class="ident">index</span>),
<span class="ident">GroupKind</span>::<span class="ident">NonCapturing</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="prelude-val">None</span>,
}
}
}
<span class="doccomment">/// The kind of a group.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">GroupKind</span> {
<span class="doccomment">/// `(a)`</span>
<span class="ident">CaptureIndex</span>(<span class="ident">u32</span>),
<span class="doccomment">/// `(?P<name>a)`</span>
<span class="ident">CaptureName</span>(<span class="ident">CaptureName</span>),
<span class="doccomment">/// `(?:a)` and `(?i:a)`</span>
<span class="ident">NonCapturing</span>(<span class="ident">Flags</span>),
}
<span class="doccomment">/// A capture name.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This corresponds to the name itself between the angle brackets in, e.g.,</span>
<span class="doccomment">/// `(?P<foo>expr)`.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">CaptureName</span> {
<span class="doccomment">/// The span of this capture name.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The capture name.</span>
<span class="kw">pub</span> <span class="ident">name</span>: <span class="ident">String</span>,
<span class="doccomment">/// The capture index.</span>
<span class="kw">pub</span> <span class="ident">index</span>: <span class="ident">u32</span>,
}
<span class="doccomment">/// A group of flags that is not applied to a particular regular expression.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">SetFlags</span> {
<span class="doccomment">/// The span of these flags, including the grouping parentheses.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The actual sequence of flags.</span>
<span class="kw">pub</span> <span class="ident">flags</span>: <span class="ident">Flags</span>,
}
<span class="doccomment">/// A group of flags.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This corresponds only to the sequence of flags themselves, e.g., `is-u`.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Flags</span> {
<span class="doccomment">/// The span of this group of flags.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// A sequence of flag items. Each item is either a flag or a negation</span>
<span class="doccomment">/// operator.</span>
<span class="kw">pub</span> <span class="ident">items</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">FlagsItem</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">Flags</span> {
<span class="doccomment">/// Add the given item to this sequence of flags.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the item was added successfully, then `None` is returned. If the</span>
<span class="doccomment">/// given item is a duplicate, then `Some(i)` is returned, where</span>
<span class="doccomment">/// `items[i].kind == item.kind`.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">add_item</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">item</span>: <span class="ident">FlagsItem</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> {
<span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">x</span>) <span class="kw">in</span> <span class="self">self</span>.<span class="ident">items</span>.<span class="ident">iter</span>().<span class="ident">enumerate</span>() {
<span class="kw">if</span> <span class="ident">x</span>.<span class="ident">kind</span> <span class="op">=</span><span class="op">=</span> <span class="ident">item</span>.<span class="ident">kind</span> {
<span class="kw">return</span> <span class="prelude-val">Some</span>(<span class="ident">i</span>);
}
}
<span class="self">self</span>.<span class="ident">items</span>.<span class="ident">push</span>(<span class="ident">item</span>);
<span class="prelude-val">None</span>
}
<span class="doccomment">/// Returns the state of the given flag in this set.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the given flag is in the set but is negated, then `Some(false)` is</span>
<span class="doccomment">/// returned.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the given flag is in the set and is not negated, then `Some(true)`</span>
<span class="doccomment">/// is returned.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Otherwise, `None` is returned.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">flag_state</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">flag</span>: <span class="ident">Flag</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">bool</span><span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">negated</span> <span class="op">=</span> <span class="bool-val">false</span>;
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">items</span> {
<span class="kw">match</span> <span class="ident">x</span>.<span class="ident">kind</span> {
<span class="ident">FlagsItemKind</span>::<span class="ident">Negation</span> <span class="op">=</span><span class="op">></span> {
<span class="ident">negated</span> <span class="op">=</span> <span class="bool-val">true</span>;
}
<span class="ident">FlagsItemKind</span>::<span class="ident">Flag</span>(<span class="kw-2">ref</span> <span class="ident">xflag</span>) <span class="kw">if</span> <span class="ident">xflag</span> <span class="op">=</span><span class="op">=</span> <span class="kw-2">&</span><span class="ident">flag</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">return</span> <span class="prelude-val">Some</span>(<span class="op">!</span><span class="ident">negated</span>);
}
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> {}
}
}
<span class="prelude-val">None</span>
}
}
<span class="doccomment">/// A single item in a group of flags.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">FlagsItem</span> {
<span class="doccomment">/// The span of this item.</span>
<span class="kw">pub</span> <span class="ident">span</span>: <span class="ident">Span</span>,
<span class="doccomment">/// The kind of this item.</span>
<span class="kw">pub</span> <span class="ident">kind</span>: <span class="ident">FlagsItemKind</span>,
}
<span class="doccomment">/// The kind of an item in a group of flags.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">FlagsItemKind</span> {
<span class="doccomment">/// A negation operator applied to all subsequent flags in the enclosing</span>
<span class="doccomment">/// group.</span>
<span class="ident">Negation</span>,
<span class="doccomment">/// A single flag in a group.</span>
<span class="ident">Flag</span>(<span class="ident">Flag</span>),
}
<span class="kw">impl</span> <span class="ident">FlagsItemKind</span> {
<span class="doccomment">/// Returns true if and only if this item is a negation operator.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_negation</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">FlagsItemKind</span>::<span class="ident">Negation</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
}
<span class="doccomment">/// A single flag.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">Flag</span> {
<span class="doccomment">/// `i`</span>
<span class="ident">CaseInsensitive</span>,
<span class="doccomment">/// `m`</span>
<span class="ident">MultiLine</span>,
<span class="doccomment">/// `s`</span>
<span class="ident">DotMatchesNewLine</span>,
<span class="doccomment">/// `U`</span>
<span class="ident">SwapGreed</span>,
<span class="doccomment">/// `u`</span>
<span class="ident">Unicode</span>,
<span class="doccomment">/// `x`</span>
<span class="ident">IgnoreWhitespace</span>,
}
<span class="doccomment">/// A custom `Drop` impl is used for `Ast` such that it uses constant stack</span>
<span class="doccomment">/// space but heap space proportional to the depth of the `Ast`.</span>
<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Ast</span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">mem</span>;
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Flags</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Literal</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Dot</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Assertion</span>(<span class="kw">_</span>)
<span class="comment">// Classes are recursive, so they get their own Drop impl.</span>
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Class</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="kw">return</span>,
<span class="ident">Ast</span>::<span class="ident">Repetition</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="kw">if</span> <span class="op">!</span><span class="ident">x</span>.<span class="ident">ast</span>.<span class="ident">has_subexprs</span>() <span class="op">=</span><span class="op">></span> <span class="kw">return</span>,
<span class="ident">Ast</span>::<span class="ident">Group</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="kw">if</span> <span class="op">!</span><span class="ident">x</span>.<span class="ident">ast</span>.<span class="ident">has_subexprs</span>() <span class="op">=</span><span class="op">></span> <span class="kw">return</span>,
<span class="ident">Ast</span>::<span class="ident">Alternation</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="kw">if</span> <span class="ident">x</span>.<span class="ident">asts</span>.<span class="ident">is_empty</span>() <span class="op">=</span><span class="op">></span> <span class="kw">return</span>,
<span class="ident">Ast</span>::<span class="ident">Concat</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="kw">if</span> <span class="ident">x</span>.<span class="ident">asts</span>.<span class="ident">is_empty</span>() <span class="op">=</span><span class="op">></span> <span class="kw">return</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> {}
}
<span class="kw">let</span> <span class="ident">empty_span</span> <span class="op">=</span> <span class="op">|</span><span class="op">|</span> <span class="ident">Span</span>::<span class="ident">splat</span>(<span class="ident">Position</span>::<span class="ident">new</span>(<span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>));
<span class="kw">let</span> <span class="ident">empty_ast</span> <span class="op">=</span> <span class="op">|</span><span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="ident">empty_span</span>());
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">stack</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="ident">mem</span>::<span class="ident">replace</span>(<span class="self">self</span>, <span class="ident">empty_ast</span>())];
<span class="kw">while</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="kw-2">mut</span> <span class="ident">ast</span>) <span class="op">=</span> <span class="ident">stack</span>.<span class="ident">pop</span>() {
<span class="kw">match</span> <span class="ident">ast</span> {
<span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Flags</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Literal</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Dot</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Assertion</span>(<span class="kw">_</span>)
<span class="comment">// Classes are recursive, so they get their own Drop impl.</span>
<span class="op">|</span> <span class="ident">Ast</span>::<span class="ident">Class</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> {}
<span class="ident">Ast</span>::<span class="ident">Repetition</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">stack</span>.<span class="ident">push</span>(<span class="ident">mem</span>::<span class="ident">replace</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">x</span>.<span class="ident">ast</span>, <span class="ident">empty_ast</span>()));
}
<span class="ident">Ast</span>::<span class="ident">Group</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">stack</span>.<span class="ident">push</span>(<span class="ident">mem</span>::<span class="ident">replace</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">x</span>.<span class="ident">ast</span>, <span class="ident">empty_ast</span>()));
}
<span class="ident">Ast</span>::<span class="ident">Alternation</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">stack</span>.<span class="ident">extend</span>(<span class="ident">x</span>.<span class="ident">asts</span>.<span class="ident">drain</span>(..));
}
<span class="ident">Ast</span>::<span class="ident">Concat</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">stack</span>.<span class="ident">extend</span>(<span class="ident">x</span>.<span class="ident">asts</span>.<span class="ident">drain</span>(..));
}
}
}
}
}
<span class="doccomment">/// A custom `Drop` impl is used for `ClassSet` such that it uses constant</span>
<span class="doccomment">/// stack space but heap space proportional to the depth of the `ClassSet`.</span>
<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">ClassSet</span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">mem</span>;
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">ClassSet</span>::<span class="ident">Item</span>(<span class="kw-2">ref</span> <span class="ident">item</span>) <span class="op">=</span><span class="op">></span> <span class="kw">match</span> <span class="kw-2">*</span><span class="ident">item</span> {
<span class="ident">ClassSetItem</span>::<span class="ident">Empty</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Literal</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Range</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Ascii</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Unicode</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Perl</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="kw">return</span>,
<span class="ident">ClassSetItem</span>::<span class="ident">Bracketed</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">x</span>.<span class="ident">kind</span>.<span class="ident">is_empty</span>() {
<span class="kw">return</span>;
}
}
<span class="ident">ClassSetItem</span>::<span class="ident">Union</span>(<span class="kw-2">ref</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">x</span>.<span class="ident">items</span>.<span class="ident">is_empty</span>() {
<span class="kw">return</span>;
}
}
},
<span class="ident">ClassSet</span>::<span class="ident">BinaryOp</span>(<span class="kw-2">ref</span> <span class="ident">op</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">op</span>.<span class="ident">lhs</span>.<span class="ident">is_empty</span>() <span class="kw-2">&</span><span class="op">&</span> <span class="ident">op</span>.<span class="ident">rhs</span>.<span class="ident">is_empty</span>() {
<span class="kw">return</span>;
}
}
}
<span class="kw">let</span> <span class="ident">empty_span</span> <span class="op">=</span> <span class="op">|</span><span class="op">|</span> <span class="ident">Span</span>::<span class="ident">splat</span>(<span class="ident">Position</span>::<span class="ident">new</span>(<span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>));
<span class="kw">let</span> <span class="ident">empty_set</span> <span class="op">=</span> <span class="op">|</span><span class="op">|</span> <span class="ident">ClassSet</span>::<span class="ident">Item</span>(<span class="ident">ClassSetItem</span>::<span class="ident">Empty</span>(<span class="ident">empty_span</span>()));
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">stack</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="ident">mem</span>::<span class="ident">replace</span>(<span class="self">self</span>, <span class="ident">empty_set</span>())];
<span class="kw">while</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="kw-2">mut</span> <span class="ident">set</span>) <span class="op">=</span> <span class="ident">stack</span>.<span class="ident">pop</span>() {
<span class="kw">match</span> <span class="ident">set</span> {
<span class="ident">ClassSet</span>::<span class="ident">Item</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">item</span>) <span class="op">=</span><span class="op">></span> <span class="kw">match</span> <span class="kw-2">*</span><span class="ident">item</span> {
<span class="ident">ClassSetItem</span>::<span class="ident">Empty</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Literal</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Range</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Ascii</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Unicode</span>(<span class="kw">_</span>)
<span class="op">|</span> <span class="ident">ClassSetItem</span>::<span class="ident">Perl</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> {}
<span class="ident">ClassSetItem</span>::<span class="ident">Bracketed</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">stack</span>.<span class="ident">push</span>(<span class="ident">mem</span>::<span class="ident">replace</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">x</span>.<span class="ident">kind</span>, <span class="ident">empty_set</span>()));
}
<span class="ident">ClassSetItem</span>::<span class="ident">Union</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">x</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">stack</span>.<span class="ident">extend</span>(<span class="ident">x</span>.<span class="ident">items</span>.<span class="ident">drain</span>(..).<span class="ident">map</span>(<span class="ident">ClassSet</span>::<span class="ident">Item</span>));
}
},
<span class="ident">ClassSet</span>::<span class="ident">BinaryOp</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">op</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">stack</span>.<span class="ident">push</span>(<span class="ident">mem</span>::<span class="ident">replace</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">op</span>.<span class="ident">lhs</span>, <span class="ident">empty_set</span>()));
<span class="ident">stack</span>.<span class="ident">push</span>(<span class="ident">mem</span>::<span class="ident">replace</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">op</span>.<span class="ident">rhs</span>, <span class="ident">empty_set</span>()));
}
}
}
}
}
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span>
<span class="kw">mod</span> <span class="ident">tests</span> {
<span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>;
<span class="comment">// We use a thread with an explicit stack size to test that our destructor</span>
<span class="comment">// for Ast can handle arbitrarily sized expressions in constant stack</span>
<span class="comment">// space. In case we run on a platform without threads (WASM?), we limit</span>
<span class="comment">// this test to Windows/Unix.</span>
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">unix</span>, <span class="ident">windows</span>))]</span>
<span class="kw">fn</span> <span class="ident">no_stack_overflow_on_drop</span>() {
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">thread</span>;
<span class="kw">let</span> <span class="ident">run</span> <span class="op">=</span> <span class="op">|</span><span class="op">|</span> {
<span class="kw">let</span> <span class="ident">span</span> <span class="op">=</span> <span class="op">|</span><span class="op">|</span> <span class="ident">Span</span>::<span class="ident">splat</span>(<span class="ident">Position</span>::<span class="ident">new</span>(<span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>));
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">ast</span> <span class="op">=</span> <span class="ident">Ast</span>::<span class="ident">Empty</span>(<span class="ident">span</span>());
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">200</span> {
<span class="ident">ast</span> <span class="op">=</span> <span class="ident">Ast</span>::<span class="ident">Group</span>(<span class="ident">Group</span> {
<span class="ident">span</span>: <span class="ident">span</span>(),
<span class="ident">kind</span>: <span class="ident">GroupKind</span>::<span class="ident">CaptureIndex</span>(<span class="ident">i</span>),
<span class="ident">ast</span>: <span class="ident">Box</span>::<span class="ident">new</span>(<span class="ident">ast</span>),
});
}
<span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">ast</span>.<span class="ident">is_empty</span>());
};
<span class="comment">// We run our test on a thread with a small stack size so we can</span>
<span class="comment">// force the issue more easily.</span>
<span class="ident">thread</span>::<span class="ident">Builder</span>::<span class="ident">new</span>()
.<span class="ident">stack_size</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">10</span>)
.<span class="ident">spawn</span>(<span class="ident">run</span>)
.<span class="ident">unwrap</span>()
.<span class="ident">join</span>()
.<span class="ident">unwrap</span>();
}
}
</pre></div>
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