[fine] Strings

oden-script/src/parser.rs

@@ -32,6 +32,7 @@ impl fmt::Display for SyntaxError {
 
 pub enum Literal {
     Float64(f64),
+    String(String),
 }
 
 pub enum UnaryOp {
@@ -198,6 +199,7 @@ impl<'a> Parser<'a> {
                 TokenKind::LeftParen => self.grouping(),
                 TokenKind::Number => self.number(),
                 TokenKind::Minus => self.unary(),
+                TokenKind::String => self.string(),
                 _ => {
                     self.error("expected an expression");
                     ExprRef::error()
@@ -236,6 +238,30 @@ impl<'a> Parser<'a> {
         self.tree.add_expr(Expr::Literal(literal, token.clone()))
     }
 
+    fn string(&mut self) -> ExprRef {
+        let token = self.previous.as_ref().unwrap();
+
+        let mut result = String::new();
+        let mut input = token.as_str().chars();
+
+        assert!(input.next().is_some()); // Delimiter
+        while let Some(ch) = input.next() {
+            match ch {
+                '\\' => match input.next().unwrap() {
+                    'n' => result.push('\n'),
+                    'r' => result.push('\r'),
+                    't' => result.push('\t'),
+                    ch => result.push(ch),
+                },
+                _ => result.push(ch),
+            }
+        }
+        result.pop(); // We pushed the other delimiter on, whoops.
+
+        let literal = Literal::String(result);
+        self.tree.add_expr(Expr::Literal(literal, token.clone()))
+    }
+
     fn grouping(&mut self) -> ExprRef {
         let result = self.expression();
         self.consume(
@@ -385,4 +411,9 @@ mod tests {
     test_expr!(add_expr, "1 + 2", "(+ 1 2)");
     test_expr!(prec_expr, "1 + 2 * 3 - 7 * 7", "(- (+ 1 (* 2 3)) (* 7 7))");
     test_expr!(unary, "-((23)) * 5", "(* (- 23) 5)");
+    test_expr!(
+        strings,
+        r#" "Hello " + "world!" "#,
+        r#"(+ "Hello " "world!")"#
+    );
 }