lex: implement string escape chars

src/lex/mod.rs

@@ -34,7 +34,7 @@ impl Iterator for Lexer<'_> {
     type Item = Result<Token, SyntaxError>;
 
     fn next(&mut self) -> Option<Result<Token, SyntaxError>> {
-        self.read_white();
+        self.read_whitespace();
 
         Some(match self.cursor.next()? {
             ';' => Ok(self.make_token(TokenKind::Semi)),
@@ -100,10 +100,14 @@ impl <'a> Lexer<'a> {
         let mut s = String::new();
 
         loop {
-            // TODO: respect escapes
             match self.cursor.next() {
                 None | Some('"') => break,
 
+                Some('\\') => match self.read_escape_seq() {
+                    Ok(c) => s.push(c),
+                    Err(e) => return Err(e),
+                },
+
                 Some('\n') => return Err(SyntaxError {
                     msg: String::from("Unexpected EOL"),
                     line: self.cursor.line(),
@@ -117,6 +121,19 @@ impl <'a> Lexer<'a> {
         Ok(self.make_token(TokenKind::StringLiteral(s)))
     }
 
+    fn read_escape_seq(&mut self) -> Result<char, SyntaxError> {
+        match self.cursor.next() {
+            Some('\\') => Ok('\\'),
+            Some('n') => Ok('\n'),
+            Some('"') => Ok('"'),
+            _ => Err(SyntaxError {
+                msg: String::from("Illegal escape sequence"),
+                line: self.token_line,
+                col: self.token_col,
+            })
+        }
+    }
+
     fn read_int_rest(&mut self, first: char) -> Token {
         let mut s = String::from(first);
 
@@ -135,7 +152,7 @@ impl <'a> Lexer<'a> {
         ))
     }
 
-    fn read_white(&mut self) -> Option<Token> {
+    fn read_whitespace(&mut self) -> Option<Token> {
         let ws = self.cursor.next_until(|c| !is_whitespace(c));
 
         if ws.len() > 0 {