Add parsing and tests for parenthesized expressions

src/compiler/parser.rs

@@ -59,6 +59,14 @@ fn next_expect_strings<'source>(
     }
 }
 
+fn next_expect_string<'source>(
+    pos: &mut usize,
+    tokens: &[Token<'source>],
+    expected_string: &str,
+) -> Token<'source> {
+    next_expect_strings(pos, tokens, &vec![expected_string])
+}
+
 fn next_expect_type<'source>(
     pos: &mut usize,
     tokens: &[Token<'source>],
@@ -83,8 +91,20 @@ fn parse_identifier<'source>(pos: &mut usize, tokens: &[Token<'source>]) -> Expr
     Identifier(token.text)
 }
 
+fn parse_parenthesized<'source>(pos: &mut usize, tokens: &[Token<'source>]) -> Expression<'source> {
+    next_expect_string(pos, tokens, "(");
+    let expression = parse_expression(pos, tokens);
+    next_expect_string(pos, tokens, ")");
+    expression
+}
+
 fn parse_factor<'source>(pos: &mut usize, tokens: &[Token<'source>]) -> Expression<'source> {
-    match peek(pos, tokens).token_type {
+    let token = &peek(pos, tokens);
+
+    if token.text == "(" {
+        return parse_parenthesized(pos, tokens);
+    }
+    match token.token_type {
         TokenType::Integer => parse_int_literal(pos, tokens),
         TokenType::Identifier => parse_identifier(pos, tokens),
         _ => panic!("Unexpected {}", peek(pos, tokens)),
@@ -245,4 +265,66 @@ mod tests {
             )
         );
     }
+
+    #[test]
+    fn test_parenthesized() {
+        let result = parse(&vec![
+            new_id("("),
+            new_int("1"),
+            new_id("+"),
+            new_int("2"),
+            new_id(")"),
+            new_id("*"),
+            new_int("3"),
+        ]);
+        assert_eq!(
+            result,
+            BinaryOp(
+                Box::new(BinaryOp(
+                    Box::new(IntLiteral(1)),
+                    "+",
+                    Box::new(IntLiteral(2))
+                )),
+                "*",
+                Box::new(IntLiteral(3)),
+            )
+        );
+
+        let result = parse(&vec![
+            new_id("("),
+            new_id("("),
+            new_int("1"),
+            new_id("-"),
+            new_int("2"),
+            new_id(")"),
+            new_id(")"),
+            new_id("/"),
+            new_int("3"),
+        ]);
+        assert_eq!(
+            result,
+            BinaryOp(
+                Box::new(BinaryOp(
+                    Box::new(IntLiteral(1)),
+                    "-",
+                    Box::new(IntLiteral(2))
+                )),
+                "/",
+                Box::new(IntLiteral(3)),
+            )
+        );
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_parenthesized_mismatched() {
+        parse(&vec![
+            new_id("("),
+            new_int("1"),
+            new_id("+"),
+            new_int("2"),
+            new_id("*"),
+            new_int("3"),
+        ]);
+    }
 }