Support c string literals

crates/syntax/src/ast/expr_ext.rs

@@ -288,6 +288,7 @@ impl ast::ArrayExpr {
 pub enum LiteralKind {
     String(ast::String),
     ByteString(ast::ByteString),
+    CString(ast::CString),
     IntNumber(ast::IntNumber),
     FloatNumber(ast::FloatNumber),
     Char(ast::Char),
@@ -319,6 +320,9 @@ impl ast::Literal {
         if let Some(t) = ast::ByteString::cast(token.clone()) {
             return LiteralKind::ByteString(t);
         }
+        if let Some(t) = ast::CString::cast(token.clone()) {
+            return LiteralKind::CString(t);
+        }
         if let Some(t) = ast::Char::cast(token.clone()) {
             return LiteralKind::Char(t);
         }

crates/syntax/src/ast/generated/tokens.rs

@@ -90,6 +90,27 @@ impl AstToken for ByteString {
     fn syntax(&self) -> &SyntaxToken { &self.syntax }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct CString {
+    pub(crate) syntax: SyntaxToken,
+}
+impl std::fmt::Display for CString {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(&self.syntax, f)
+    }
+}
+impl AstToken for CString {
+    fn can_cast(kind: SyntaxKind) -> bool { kind == C_STRING }
+    fn cast(syntax: SyntaxToken) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    fn syntax(&self) -> &SyntaxToken { &self.syntax }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct IntNumber {
     pub(crate) syntax: SyntaxToken,

crates/syntax/src/ast/token_ext.rs

@@ -145,6 +145,10 @@ impl QuoteOffsets {
 }
 
 pub trait IsString: AstToken {
+    const RAW_PREFIX: &'static str;
+    fn is_raw(&self) -> bool {
+        self.text().starts_with(Self::RAW_PREFIX)
+    }
     fn quote_offsets(&self) -> Option<QuoteOffsets> {
         let text = self.text();
         let offsets = QuoteOffsets::new(text)?;
@@ -183,20 +187,18 @@ pub trait IsString: AstToken {
             cb(text_range + offset, unescaped_char);
         });
     }
-}
-
-impl IsString for ast::String {}
-
-impl ast::String {
-    pub fn is_raw(&self) -> bool {
-        self.text().starts_with('r')
-    }
-    pub fn map_range_up(&self, range: TextRange) -> Option<TextRange> {
+    fn map_range_up(&self, range: TextRange) -> Option<TextRange> {
         let contents_range = self.text_range_between_quotes()?;
         assert!(TextRange::up_to(contents_range.len()).contains_range(range));
         Some(range + contents_range.start())
     }
+}
 
+impl IsString for ast::String {
+    const RAW_PREFIX: &'static str = "r";
+}
+
+impl ast::String {
     pub fn value(&self) -> Option<Cow<'_, str>> {
         if self.is_raw() {
             let text = self.text();
@@ -235,13 +237,11 @@ impl ast::String {
     }
 }
 
-impl IsString for ast::ByteString {}
+impl IsString for ast::ByteString {
+    const RAW_PREFIX: &'static str = "br";
+}
 
 impl ast::ByteString {
-    pub fn is_raw(&self) -> bool {
-        self.text().starts_with("br")
-    }
-
     pub fn value(&self) -> Option<Cow<'_, [u8]>> {
         if self.is_raw() {
             let text = self.text();
@@ -280,6 +280,49 @@ impl ast::ByteString {
     }
 }
 
+impl IsString for ast::CString {
+    const RAW_PREFIX: &'static str = "cr";
+}
+
+impl ast::CString {
+    pub fn value(&self) -> Option<Cow<'_, str>> {
+        if self.is_raw() {
+            let text = self.text();
+            let text =
+                &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
+            return Some(Cow::Borrowed(text));
+        }
+
+        let text = self.text();
+        let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
+
+        let mut buf = String::new();
+        let mut prev_end = 0;
+        let mut has_error = false;
+        unescape_literal(text, Mode::Str, &mut |char_range, unescaped_char| match (
+            unescaped_char,
+            buf.capacity() == 0,
+        ) {
+            (Ok(c), false) => buf.push(c),
+            (Ok(_), true) if char_range.len() == 1 && char_range.start == prev_end => {
+                prev_end = char_range.end
+            }
+            (Ok(c), true) => {
+                buf.reserve_exact(text.len());
+                buf.push_str(&text[..prev_end]);
+                buf.push(c);
+            }
+            (Err(_), _) => has_error = true,
+        });
+
+        match (has_error, buf.capacity() == 0) {
+            (true, _) => None,
+            (false, true) => Some(Cow::Borrowed(text)),
+            (false, false) => Some(Cow::Owned(buf)),
+        }
+    }
+}
+
 impl ast::IntNumber {
     pub fn radix(&self) -> Radix {
         match self.text().get(..2).unwrap_or_default() {