webidl: initial enum support

Add enum support to the WebIDL interface generator.

crates/backend/src/ast.rs

@@ -41,6 +41,7 @@ pub enum ImportKind {
     Function(ImportFunction),
     Static(ImportStatic),
     Type(ImportType),
+    Enum(ImportEnum),
 }
 
 #[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
@@ -99,6 +100,18 @@ pub struct ImportType {
     pub attrs: Vec<syn::Attribute>,
 }
 
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
+pub struct ImportEnum {
+    /// The Rust enum's visibility
+    pub vis: syn::Visibility,
+    /// The Rust enum's identifiers
+    pub name: Ident,
+    /// The Rust identifiers for the variants
+    pub variants: Vec<Ident>,
+    /// The JS string values of the variants
+    pub variant_values: Vec<String>,
+}
+
 #[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Function {
     pub name: Ident,
@@ -279,6 +292,7 @@ impl ImportKind {
             ImportKind::Function(_) => true,
             ImportKind::Static(_) => false,
             ImportKind::Type(_) => false,
+            ImportKind::Enum(_) => false,
         }
     }
 
@@ -287,6 +301,7 @@ impl ImportKind {
             ImportKind::Function(ref f) => shared::ImportKind::Function(f.shared()),
             ImportKind::Static(ref f) => shared::ImportKind::Static(f.shared()),
             ImportKind::Type(ref f) => shared::ImportKind::Type(f.shared()),
+            ImportKind::Enum(ref f) => shared::ImportKind::Enum(f.shared()),
         }
     }
 }
@@ -364,6 +379,12 @@ impl ImportType {
     }
 }
 
+impl ImportEnum {
+    fn shared(&self) -> shared::ImportEnum {
+        shared::ImportEnum {}
+    }
+}
+
 impl Struct {
     fn shared(&self) -> shared::Struct {
         shared::Struct {