<!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/error.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>error.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="kw">use</span> <span class="ident">std</span>::<span class="ident">cmp</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">use</span> <span class="ident">std</span>::<span class="ident">result</span>;
<span class="kw">use</span> <span class="ident">ast</span>;
<span class="kw">use</span> <span class="ident">hir</span>;
<span class="doccomment">/// A type alias for dealing with errors returned by this crate.</span>
<span class="kw">pub</span> <span class="kw">type</span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="op">=</span> <span class="ident">result</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">Error</span><span class="op">></span>;
<span class="doccomment">/// This error type encompasses any error that can be returned by this crate.</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">Error</span> {
<span class="doccomment">/// An error that occurred while translating concrete syntax into abstract</span>
<span class="doccomment">/// syntax (AST).</span>
<span class="ident">Parse</span>(<span class="ident">ast</span>::<span class="ident">Error</span>),
<span class="doccomment">/// An error that occurred while translating abstract syntax into a high</span>
<span class="doccomment">/// level intermediate representation (HIR).</span>
<span class="ident">Translate</span>(<span class="ident">hir</span>::<span class="ident">Error</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">From</span><span class="op"><</span><span class="ident">ast</span>::<span class="ident">Error</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Error</span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">err</span>: <span class="ident">ast</span>::<span class="ident">Error</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Error</span> {
<span class="ident">Error</span>::<span class="ident">Parse</span>(<span class="ident">err</span>)
}
}
<span class="kw">impl</span> <span class="ident">From</span><span class="op"><</span><span class="ident">hir</span>::<span class="ident">Error</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Error</span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">err</span>: <span class="ident">hir</span>::<span class="ident">Error</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Error</span> {
<span class="ident">Error</span>::<span class="ident">Translate</span>(<span class="ident">err</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">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Error</span>::<span class="ident">Parse</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">description</span>(),
<span class="ident">Error</span>::<span class="ident">Translate</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">description</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="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Error</span>::<span class="ident">Parse</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">fmt</span>(<span class="ident">f</span>),
<span class="ident">Error</span>::<span class="ident">Translate</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">fmt</span>(<span class="ident">f</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">/// A helper type for formatting nice error messages.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This type is responsible for reporting regex parse errors in a nice human</span>
<span class="doccomment">/// readable format. Most of its complexity is from interspersing notational</span>
<span class="doccomment">/// markers pointing out the position where an error occurred.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Formatter</span><span class="op"><</span><span class="lifetime">'e</span>, <span class="ident">E</span>: <span class="lifetime">'e</span><span class="op">></span> {
<span class="doccomment">/// The original regex pattern in which the error occurred.</span>
<span class="ident">pattern</span>: <span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">str</span>,
<span class="doccomment">/// The error kind. It must impl fmt::Display.</span>
<span class="ident">err</span>: <span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">E</span>,
<span class="doccomment">/// The primary span of the error.</span>
<span class="ident">span</span>: <span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">ast</span>::<span class="ident">Span</span>,
<span class="doccomment">/// An auxiliary and optional span, in case the error needs to point to</span>
<span class="doccomment">/// two locations (e.g., when reporting a duplicate capture group name).</span>
<span class="ident">aux_span</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">ast</span>::<span class="ident">Span</span><span class="op">></span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'e</span><span class="op">></span> <span class="ident">From</span><span class="op"><</span><span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">ast</span>::<span class="ident">Error</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Formatter</span><span class="op"><</span><span class="lifetime">'e</span>, <span class="ident">ast</span>::<span class="ident">ErrorKind</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">err</span>: <span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">ast</span>::<span class="ident">Error</span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">Formatter</span> {
<span class="ident">pattern</span>: <span class="ident">err</span>.<span class="ident">pattern</span>(),
<span class="ident">err</span>: <span class="ident">err</span>.<span class="ident">kind</span>(),
<span class="ident">span</span>: <span class="ident">err</span>.<span class="ident">span</span>(),
<span class="ident">aux_span</span>: <span class="ident">err</span>.<span class="ident">auxiliary_span</span>(),
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'e</span><span class="op">></span> <span class="ident">From</span><span class="op"><</span><span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">hir</span>::<span class="ident">Error</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Formatter</span><span class="op"><</span><span class="lifetime">'e</span>, <span class="ident">hir</span>::<span class="ident">ErrorKind</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">err</span>: <span class="kw-2">&</span><span class="lifetime">'e</span> <span class="ident">hir</span>::<span class="ident">Error</span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">Formatter</span> {
<span class="ident">pattern</span>: <span class="ident">err</span>.<span class="ident">pattern</span>(),
<span class="ident">err</span>: <span class="ident">err</span>.<span class="ident">kind</span>(),
<span class="ident">span</span>: <span class="ident">err</span>.<span class="ident">span</span>(),
<span class="ident">aux_span</span>: <span class="prelude-val">None</span>,
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'e</span>, <span class="ident">E</span>: <span class="ident">fmt</span>::<span class="ident">Display</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Display</span> <span class="kw">for</span> <span class="ident">Formatter</span><span class="op"><</span><span class="lifetime">'e</span>, <span class="ident">E</span><span class="op">></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">let</span> <span class="ident">spans</span> <span class="op">=</span> <span class="ident">Spans</span>::<span class="ident">from_formatter</span>(<span class="self">self</span>);
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">pattern</span>.<span class="ident">contains</span>(<span class="string">'\n'</span>) {
<span class="kw">let</span> <span class="ident">divider</span> <span class="op">=</span> <span class="ident">repeat_char</span>(<span class="string">'~'</span>, <span class="number">79</span>);
<span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"regex parse error:"</span>)<span class="question-mark">?</span>;
<span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"{}"</span>, <span class="ident">divider</span>)<span class="question-mark">?</span>;
<span class="kw">let</span> <span class="ident">notated</span> <span class="op">=</span> <span class="ident">spans</span>.<span class="ident">notate</span>();
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"{}"</span>, <span class="ident">notated</span>)<span class="question-mark">?</span>;
<span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"{}"</span>, <span class="ident">divider</span>)<span class="question-mark">?</span>;
<span class="comment">// If we have error spans that cover multiple lines, then we just</span>
<span class="comment">// note the line numbers.</span>
<span class="kw">if</span> <span class="op">!</span><span class="ident">spans</span>.<span class="ident">multi_line</span>.<span class="ident">is_empty</span>() {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">notes</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[];
<span class="kw">for</span> <span class="ident">span</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">spans</span>.<span class="ident">multi_line</span> {
<span class="ident">notes</span>.<span class="ident">push</span>(<span class="macro">format</span><span class="macro">!</span>(
<span class="string">"on line {} (column {}) through line {} (column {})"</span>,
<span class="ident">span</span>.<span class="ident">start</span>.<span class="ident">line</span>,
<span class="ident">span</span>.<span class="ident">start</span>.<span class="ident">column</span>,
<span class="ident">span</span>.<span class="ident">end</span>.<span class="ident">line</span>,
<span class="ident">span</span>.<span class="ident">end</span>.<span class="ident">column</span> <span class="op">-</span> <span class="number">1</span>
));
}
<span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"{}"</span>, <span class="ident">notes</span>.<span class="ident">join</span>(<span class="string">"\n"</span>))<span class="question-mark">?</span>;
}
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"error: {}"</span>, <span class="self">self</span>.<span class="ident">err</span>)<span class="question-mark">?</span>;
} <span class="kw">else</span> {
<span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"regex parse error:"</span>)<span class="question-mark">?</span>;
<span class="kw">let</span> <span class="ident">notated</span> <span class="op">=</span> <span class="ident">Spans</span>::<span class="ident">from_formatter</span>(<span class="self">self</span>).<span class="ident">notate</span>();
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"{}"</span>, <span class="ident">notated</span>)<span class="question-mark">?</span>;
<span class="macro">write</span><span class="macro">!</span>(<span class="ident">f</span>, <span class="string">"error: {}"</span>, <span class="self">self</span>.<span class="ident">err</span>)<span class="question-mark">?</span>;
}
<span class="prelude-val">Ok</span>(())
}
}
<span class="doccomment">/// This type represents an arbitrary number of error spans in a way that makes</span>
<span class="doccomment">/// it convenient to notate the regex pattern. ("Notate" means "point out</span>
<span class="doccomment">/// exactly where the error occurred in the regex pattern.")</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Technically, we can only ever have two spans given our current error</span>
<span class="doccomment">/// structure. However, after toiling with a specific algorithm for handling</span>
<span class="doccomment">/// two spans, it became obvious that an algorithm to handle an arbitrary</span>
<span class="doccomment">/// number of spans was actually much simpler.</span>
<span class="kw">struct</span> <span class="ident">Spans</span><span class="op"><</span><span class="lifetime">'p</span><span class="op">></span> {
<span class="doccomment">/// The original regex pattern string.</span>
<span class="ident">pattern</span>: <span class="kw-2">&</span><span class="lifetime">'p</span> <span class="ident">str</span>,
<span class="doccomment">/// The total width that should be used for line numbers. The width is</span>
<span class="doccomment">/// used for left padding the line numbers for alignment.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A value of `0` means line numbers should not be displayed. That is,</span>
<span class="doccomment">/// the pattern is itself only one line.</span>
<span class="ident">line_number_width</span>: <span class="ident">usize</span>,
<span class="doccomment">/// All error spans that occur on a single line. This sequence always has</span>
<span class="doccomment">/// length equivalent to the number of lines in `pattern`, where the index</span>
<span class="doccomment">/// of the sequence represents a line number, starting at `0`. The spans</span>
<span class="doccomment">/// in each line are sorted in ascending order.</span>
<span class="ident">by_line</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="ident">ast</span>::<span class="ident">Span</span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// All error spans that occur over one or more lines. That is, the start</span>
<span class="doccomment">/// and end position of the span have different line numbers. The spans are</span>
<span class="doccomment">/// sorted in ascending order.</span>
<span class="ident">multi_line</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">ast</span>::<span class="ident">Span</span><span class="op">></span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'p</span><span class="op">></span> <span class="ident">Spans</span><span class="op"><</span><span class="lifetime">'p</span><span class="op">></span> {
<span class="doccomment">/// Build a sequence of spans from a formatter.</span>
<span class="kw">fn</span> <span class="ident">from_formatter</span><span class="op"><</span><span class="lifetime">'e</span>, <span class="ident">E</span>: <span class="ident">fmt</span>::<span class="ident">Display</span><span class="op">></span>(
<span class="ident">fmter</span>: <span class="kw-2">&</span><span class="lifetime">'p</span> <span class="ident">Formatter</span><span class="op"><</span><span class="lifetime">'e</span>, <span class="ident">E</span><span class="op">></span>,
) <span class="op">-</span><span class="op">></span> <span class="ident">Spans</span><span class="op"><</span><span class="lifetime">'p</span><span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">line_count</span> <span class="op">=</span> <span class="ident">fmter</span>.<span class="ident">pattern</span>.<span class="ident">lines</span>().<span class="ident">count</span>();
<span class="comment">// If the pattern ends with a `\n` literal, then our line count is</span>
<span class="comment">// off by one, since a span can occur immediately after the last `\n`,</span>
<span class="comment">// which is consider to be an additional line.</span>
<span class="kw">if</span> <span class="ident">fmter</span>.<span class="ident">pattern</span>.<span class="ident">ends_with</span>(<span class="string">'\n'</span>) {
<span class="ident">line_count</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
}
<span class="kw">let</span> <span class="ident">line_number_width</span> <span class="op">=</span>
<span class="kw">if</span> <span class="ident">line_count</span> <span class="op"><</span><span class="op">=</span> <span class="number">1</span> { <span class="number">0</span> } <span class="kw">else</span> { <span class="ident">line_count</span>.<span class="ident">to_string</span>().<span class="ident">len</span>() };
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">spans</span> <span class="op">=</span> <span class="ident">Spans</span> {
<span class="ident">pattern</span>: <span class="kw-2">&</span><span class="ident">fmter</span>.<span class="ident">pattern</span>,
<span class="ident">line_number_width</span>: <span class="ident">line_number_width</span>,
<span class="ident">by_line</span>: <span class="macro">vec</span><span class="macro">!</span>[<span class="macro">vec</span><span class="macro">!</span>[]; <span class="ident">line_count</span>],
<span class="ident">multi_line</span>: <span class="macro">vec</span><span class="macro">!</span>[],
};
<span class="ident">spans</span>.<span class="ident">add</span>(<span class="ident">fmter</span>.<span class="ident">span</span>.<span class="ident">clone</span>());
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">span</span>) <span class="op">=</span> <span class="ident">fmter</span>.<span class="ident">aux_span</span> {
<span class="ident">spans</span>.<span class="ident">add</span>(<span class="ident">span</span>.<span class="ident">clone</span>());
}
<span class="ident">spans</span>
}
<span class="doccomment">/// Add the given span to this sequence, putting it in the right place.</span>
<span class="kw">fn</span> <span class="ident">add</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">span</span>: <span class="ident">ast</span>::<span class="ident">Span</span>) {
<span class="comment">// This is grossly inefficient since we sort after each add, but right</span>
<span class="comment">// now, we only ever add two spans at most.</span>
<span class="kw">if</span> <span class="ident">span</span>.<span class="ident">is_one_line</span>() {
<span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span> <span class="ident">span</span>.<span class="ident">start</span>.<span class="ident">line</span> <span class="op">-</span> <span class="number">1</span>; <span class="comment">// because lines are 1-indexed</span>
<span class="self">self</span>.<span class="ident">by_line</span>[<span class="ident">i</span>].<span class="ident">push</span>(<span class="ident">span</span>);
<span class="self">self</span>.<span class="ident">by_line</span>[<span class="ident">i</span>].<span class="ident">sort</span>();
} <span class="kw">else</span> {
<span class="self">self</span>.<span class="ident">multi_line</span>.<span class="ident">push</span>(<span class="ident">span</span>);
<span class="self">self</span>.<span class="ident">multi_line</span>.<span class="ident">sort</span>();
}
}
<span class="doccomment">/// Notate the pattern string with carents (`^`) pointing at each span</span>
<span class="doccomment">/// location. This only applies to spans that occur within a single line.</span>
<span class="kw">fn</span> <span class="ident">notate</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">String</span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">notated</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">new</span>();
<span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">line</span>) <span class="kw">in</span> <span class="self">self</span>.<span class="ident">pattern</span>.<span class="ident">lines</span>().<span class="ident">enumerate</span>() {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">line_number_width</span> <span class="op">></span> <span class="number">0</span> {
<span class="ident">notated</span>.<span class="ident">push_str</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">left_pad_line_number</span>(<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>));
<span class="ident">notated</span>.<span class="ident">push_str</span>(<span class="string">": "</span>);
} <span class="kw">else</span> {
<span class="ident">notated</span>.<span class="ident">push_str</span>(<span class="string">" "</span>);
}
<span class="ident">notated</span>.<span class="ident">push_str</span>(<span class="ident">line</span>);
<span class="ident">notated</span>.<span class="ident">push</span>(<span class="string">'\n'</span>);
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">notes</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">notate_line</span>(<span class="ident">i</span>) {
<span class="ident">notated</span>.<span class="ident">push_str</span>(<span class="kw-2">&</span><span class="ident">notes</span>);
<span class="ident">notated</span>.<span class="ident">push</span>(<span class="string">'\n'</span>);
}
}
<span class="ident">notated</span>
}
<span class="doccomment">/// Return notes for the line indexed at `i` (zero-based). If there are no</span>
<span class="doccomment">/// spans for the given line, then `None` is returned. Otherwise, an</span>
<span class="doccomment">/// appropriately space padded string with correctly positioned `^` is</span>
<span class="doccomment">/// returned, accounting for line numbers.</span>
<span class="kw">fn</span> <span class="ident">notate_line</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">i</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">String</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">spans</span> <span class="op">=</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">by_line</span>[<span class="ident">i</span>];
<span class="kw">if</span> <span class="ident">spans</span>.<span class="ident">is_empty</span>() {
<span class="kw">return</span> <span class="prelude-val">None</span>;
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">notes</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">new</span>();
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="self">self</span>.<span class="ident">line_number_padding</span>() {
<span class="ident">notes</span>.<span class="ident">push</span>(<span class="string">' '</span>);
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">pos</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">for</span> <span class="ident">span</span> <span class="kw">in</span> <span class="ident">spans</span> {
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="ident">pos</span>..(<span class="ident">span</span>.<span class="ident">start</span>.<span class="ident">column</span> <span class="op">-</span> <span class="number">1</span>) {
<span class="ident">notes</span>.<span class="ident">push</span>(<span class="string">' '</span>);
<span class="ident">pos</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
}
<span class="kw">let</span> <span class="ident">note_len</span> <span class="op">=</span> <span class="ident">span</span>.<span class="ident">end</span>.<span class="ident">column</span>.<span class="ident">saturating_sub</span>(<span class="ident">span</span>.<span class="ident">start</span>.<span class="ident">column</span>);
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">cmp</span>::<span class="ident">max</span>(<span class="number">1</span>, <span class="ident">note_len</span>) {
<span class="ident">notes</span>.<span class="ident">push</span>(<span class="string">'^'</span>);
<span class="ident">pos</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
}
}
<span class="prelude-val">Some</span>(<span class="ident">notes</span>)
}
<span class="doccomment">/// Left pad the given line number with spaces such that it is aligned with</span>
<span class="doccomment">/// other line numbers.</span>
<span class="kw">fn</span> <span class="ident">left_pad_line_number</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">n</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">String</span> {
<span class="kw">let</span> <span class="ident">n</span> <span class="op">=</span> <span class="ident">n</span>.<span class="ident">to_string</span>();
<span class="kw">let</span> <span class="ident">pad</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">line_number_width</span>.<span class="ident">checked_sub</span>(<span class="ident">n</span>.<span class="ident">len</span>()).<span class="ident">unwrap</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">repeat_char</span>(<span class="string">' '</span>, <span class="ident">pad</span>);
<span class="ident">result</span>.<span class="ident">push_str</span>(<span class="kw-2">&</span><span class="ident">n</span>);
<span class="ident">result</span>
}
<span class="doccomment">/// Return the line number padding beginning at the start of each line of</span>
<span class="doccomment">/// the pattern.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the pattern is only one line, then this returns a fixed padding</span>
<span class="doccomment">/// for visual indentation.</span>
<span class="kw">fn</span> <span class="ident">line_number_padding</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">usize</span> {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">line_number_width</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="number">4</span>
} <span class="kw">else</span> {
<span class="number">2</span> <span class="op">+</span> <span class="self">self</span>.<span class="ident">line_number_width</span>
}
}
}
<span class="kw">fn</span> <span class="ident">repeat_char</span>(<span class="ident">c</span>: <span class="ident">char</span>, <span class="ident">count</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">String</span> {
::<span class="ident">std</span>::<span class="ident">iter</span>::<span class="ident">repeat</span>(<span class="ident">c</span>).<span class="ident">take</span>(<span class="ident">count</span>).<span class="ident">collect</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="ident">ast</span>::<span class="ident">parse</span>::<span class="ident">Parser</span>;
<span class="kw">fn</span> <span class="ident">assert_panic_message</span>(<span class="ident">pattern</span>: <span class="kw-2">&</span><span class="ident">str</span>, <span class="ident">expected_msg</span>: <span class="kw-2">&</span><span class="ident">str</span>) <span class="op">-</span><span class="op">></span> () {
<span class="kw">let</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">Parser</span>::<span class="ident">new</span>().<span class="ident">parse</span>(<span class="ident">pattern</span>);
<span class="kw">match</span> <span class="ident">result</span> {
<span class="prelude-val">Ok</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> {
<span class="macro">panic</span><span class="macro">!</span>(<span class="string">"regex should not have parsed"</span>);
}
<span class="prelude-val">Err</span>(<span class="ident">err</span>) <span class="op">=</span><span class="op">></span> {
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">err</span>.<span class="ident">to_string</span>(), <span class="ident">expected_msg</span>.<span class="ident">trim</span>());
}
}
}
<span class="comment">// See: https://github.com/rust-lang/regex/issues/464</span>
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">regression_464</span>() {
<span class="kw">let</span> <span class="ident">err</span> <span class="op">=</span> <span class="ident">Parser</span>::<span class="ident">new</span>().<span class="ident">parse</span>(<span class="string">"a{\n"</span>).<span class="ident">unwrap_err</span>();
<span class="comment">// This test checks that the error formatter doesn't panic.</span>
<span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">err</span>.<span class="ident">to_string</span>().<span class="ident">is_empty</span>());
}
<span class="comment">// See: https://github.com/rust-lang/regex/issues/545</span>
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">repetition_quantifier_expects_a_valid_decimal</span>() {
<span class="ident">assert_panic_message</span>(
<span class="string">r"\\u{[^}]*}"</span>,
<span class="string">r#"
regex parse error:
\\u{[^}]*}
^
error: repetition quantifier expects a valid decimal
"#</span>,
);
}
}
</pre></div>
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