Merge pull request #26 from microsoft/fixup

Fixup

Author: niclasko

flowquery-py/src/parsing/parser.py

@@ -683,12 +683,7 @@ def _parse_operand(self, expression: Expression) -> bool:
                 return True
         elif (
             self.token.is_left_parenthesis()
-            and self.peek() is not None
-            and (
-                self.peek().is_identifier_or_keyword()
-                or self.peek().is_colon()
-                or self.peek().is_right_parenthesis()
-            )
+            and self._looks_like_node_pattern()
         ):
             # Possible graph pattern expression
             pattern = self._parse_pattern_expression()
@@ -779,6 +774,34 @@ def _parse_expression(self) -> Optional[Expression]:
             return expression
         return None
 
+    def _looks_like_node_pattern(self) -> bool:
+        """Peek ahead from a left parenthesis to determine whether the
+        upcoming tokens form a graph-node pattern (e.g. (n:Label), (n),
+        (:Label), ()) rather than a parenthesised expression (e.g.
+        (variable.property), (a + b)).
+        """
+        saved_index = self._token_index
+        self.set_next_token()  # skip '('
+        self._skip_whitespace_and_comments()
+
+        if self.token.is_colon() or self.token.is_right_parenthesis():
+            self._token_index = saved_index
+            return True
+
+        if self.token.is_identifier_or_keyword():
+            self.set_next_token()  # skip identifier
+            self._skip_whitespace_and_comments()
+            result = (
+                self.token.is_colon()
+                or self.token.is_opening_brace()
+                or self.token.is_right_parenthesis()
+            )
+            self._token_index = saved_index
+            return result
+
+        self._token_index = saved_index
+        return False
+
     def _parse_is_operator(self) -> ASTNode:
         """Parse IS or IS NOT operator."""
         # Current token is IS. Look ahead for NOT to produce IS NOT.

flowquery-py/tests/parsing/test_parser.py

@@ -1032,3 +1032,61 @@ def test_where_with_not_ends_with(self):
             "--- Reference (s)"
         )
         assert ast.print() == expected
+
+    def test_parenthesized_expression_with_addition(self):
+        """Test that (variable + number) is parsed as a parenthesized expression, not a node."""
+        parser = Parser()
+        ast = parser.parse("WITH 1 AS n RETURN (n + 2)")
+        expected = (
+            "ASTNode\n"
+            "- With\n"
+            "-- Expression (n)\n"
+            "--- Number (1)\n"
+            "- Return\n"
+            "-- Expression\n"
+            "--- Expression\n"
+            "---- Add\n"
+            "----- Reference (n)\n"
+            "----- Number (2)"
+        )
+        assert ast.print() == expected
+
+    def test_parenthesized_expression_with_property_access(self):
+        """Test that (obj.property) is parsed as a parenthesized expression, not a node."""
+        parser = Parser()
+        ast = parser.parse("WITH {a: 1} AS obj RETURN (obj.a)")
+        expected = (
+            "ASTNode\n"
+            "- With\n"
+            "-- Expression (obj)\n"
+            "--- AssociativeArray\n"
+            "---- KeyValuePair\n"
+            "----- String (a)\n"
+            "----- Expression\n"
+            "------ Number (1)\n"
+            "- Return\n"
+            "-- Expression\n"
+            "--- Expression\n"
+            "---- Lookup\n"
+            "----- Identifier (a)\n"
+            "----- Reference (obj)"
+        )
+        assert ast.print() == expected
+
+    def test_parenthesized_expression_with_multiplication(self):
+        """Test that (variable * number) is parsed as a parenthesized expression, not a node."""
+        parser = Parser()
+        ast = parser.parse("WITH 5 AS x RETURN (x * 3)")
+        expected = (
+            "ASTNode\n"
+            "- With\n"
+            "-- Expression (x)\n"
+            "--- Number (5)\n"
+            "- Return\n"
+            "-- Expression\n"
+            "--- Expression\n"
+            "---- Multiply\n"
+            "----- Reference (x)\n"
+            "----- Number (3)"
+        )
+        assert ast.print() == expected

src/parsing/parser.ts

@@ -798,12 +798,7 @@ class Parser extends BaseParser {
                 expression.addNode(lookup);
                 return true;
             }
-        } else if (
-            this.token.isLeftParenthesis() &&
-            (this.peek()?.isIdentifierOrKeyword() ||
-                this.peek()?.isColon() ||
-                this.peek()?.isRightParenthesis())
-        ) {
+        } else if (this.token.isLeftParenthesis() && this.looksLikeNodePattern()) {
             // Possible graph pattern expression
             const pattern = this.parsePatternExpression();
             if (pattern !== null) {
@@ -865,6 +860,42 @@ class Parser extends BaseParser {
         return false;
     }
 
+    /**
+     * Peeks ahead from a left parenthesis to determine whether the
+     * upcoming tokens form a graph-node pattern (e.g. (n:Label), (n),
+     * (:Label), ()) rather than a parenthesised expression (e.g.
+     * (variable.property), (a + b)).
+     *
+     * The heuristic is:
+     *   • ( followed by `:` or `)` → node pattern
+     *   • ( identifier, then `:` or `{` or `)` → node pattern
+     *   • anything else → parenthesised expression
+     */
+    private looksLikeNodePattern(): boolean {
+        const savedIndex = this.tokenIndex;
+        this.setNextToken(); // skip '('
+        this.skipWhitespaceAndComments();
+
+        if (this.token.isColon() || this.token.isRightParenthesis()) {
+            this.tokenIndex = savedIndex;
+            return true;
+        }
+
+        if (this.token.isIdentifierOrKeyword()) {
+            this.setNextToken(); // skip identifier
+            this.skipWhitespaceAndComments();
+            const result =
+                this.token.isColon() ||
+                this.token.isOpeningBrace() ||
+                this.token.isRightParenthesis();
+            this.tokenIndex = savedIndex;
+            return result;
+        }
+
+        this.tokenIndex = savedIndex;
+        return false;
+    }
+
     private parseExpression(): Expression | null {
         const expression = new Expression();
         while (true) {

tests/parsing/parser.test.ts

@@ -1098,3 +1098,61 @@ test("Test WHERE with NOT ENDS WITH", () => {
         "--- Reference (s)"
     );
 });
+
+test("Test parenthesized expression with addition", () => {
+    const parser = new Parser();
+    const ast = parser.parse("WITH 1 AS n RETURN (n + 2)");
+    // prettier-ignore
+    expect(ast.print()).toBe(
+        "ASTNode\n" +
+        "- With\n" +
+        "-- Expression (n)\n" +
+        "--- Number (1)\n" +
+        "- Return\n" +
+        "-- Expression\n" +
+        "--- Expression\n" +
+        "---- Add\n" +
+        "----- Reference (n)\n" +
+        "----- Number (2)"
+    );
+});
+
+test("Test parenthesized expression with property access", () => {
+    const parser = new Parser();
+    const ast = parser.parse("WITH {a: 1} AS obj RETURN (obj.a)");
+    // prettier-ignore
+    expect(ast.print()).toBe(
+        "ASTNode\n" +
+        "- With\n" +
+        "-- Expression (obj)\n" +
+        "--- AssociativeArray\n" +
+        "---- KeyValuePair\n" +
+        "----- String (a)\n" +
+        "----- Expression\n" +
+        "------ Number (1)\n" +
+        "- Return\n" +
+        "-- Expression\n" +
+        "--- Expression\n" +
+        "---- Lookup\n" +
+        "----- Identifier (a)\n" +
+        "----- Reference (obj)"
+    );
+});
+
+test("Test parenthesized expression with multiplication", () => {
+    const parser = new Parser();
+    const ast = parser.parse("WITH 5 AS x RETURN (x * 3)");
+    // prettier-ignore
+    expect(ast.print()).toBe(
+        "ASTNode\n" +
+        "- With\n" +
+        "-- Expression (x)\n" +
+        "--- Number (5)\n" +
+        "- Return\n" +
+        "-- Expression\n" +
+        "--- Expression\n" +
+        "---- Multiply\n" +
+        "----- Reference (x)\n" +
+        "----- Number (3)"
+    );
+});