Merge pull request glayzzle#485 from czosel/fix-right-associative-operators

fix: handle right-associative operators ** and ??

Author: ichiriac

src/ast.js

@@ -164,7 +164,8 @@ AST.precedence = {};
   ["*", "/", "%"],
   ["!"],
   ["instanceof"],
-  ["cast", "silent"]
+  ["cast", "silent"],
+  ["**"]
   // TODO: [ (array)
   // TODO: clone, new
 ].forEach(function(list, index) {
@@ -173,6 +174,10 @@ AST.precedence = {};
   });
 });
 
+AST.prototype.isRightAssociative = function(operator) {
+  return operator === "**" || operator === "??";
+};
+
 /**
  * Change parent node informations after swapping childs
  */
@@ -230,7 +235,12 @@ AST.prototype.resolvePrecedence = function(result, parser) {
       if (result.right.kind === "bin") {
         lLevel = AST.precedence[result.type];
         rLevel = AST.precedence[result.right.type];
-        if (lLevel && rLevel && rLevel <= lLevel) {
+        if (
+          lLevel &&
+          rLevel &&
+          rLevel <= lLevel &&
+          !this.isRightAssociative(result.type)
+        ) {
           // https://github.com/glayzzle/php-parser/issues/79
           // shift precedence
           buffer = result.right;

test/precedence.test.js

@@ -86,6 +86,12 @@ describe("Test precedence", function() {
   it("test ??", function() {
     shouldBeSame("1 || 2 ?? 3", "(1 || 2) ?? 3");
   });
+  it("test ?? right-associative", function() {
+    shouldBeSame("1 ?? 2 ?? 3", "1 ?? (2 ?? 3)");
+  });
+  it("test ** right-associative", function() {
+    shouldBeSame("1 ** 2 ** 3", "1 ** (2 ** 3)");
+  });
   it("test ?:", function() {
     shouldBeSame("1 ?? 2 ? 3 : 5", "(1 ?? 2) ? 3 : 5");
     shouldBeSame("1 and 2 ? 3 : 5", "1 and (2 ? 3 : 5)");

test/snapshot/__snapshots__/bin.test.js.snap

@@ -182,6 +182,41 @@ Program {
 }
 `;
 
+exports[`bin ** right-associative 1`] = `
+Program {
+  "children": Array [
+    ExpressionStatement {
+      "expression": Bin {
+        "kind": "bin",
+        "left": Variable {
+          "curly": false,
+          "kind": "variable",
+          "name": "a",
+        },
+        "right": Bin {
+          "kind": "bin",
+          "left": Variable {
+            "curly": false,
+            "kind": "variable",
+            "name": "b",
+          },
+          "right": Variable {
+            "curly": false,
+            "kind": "variable",
+            "name": "c",
+          },
+          "type": "**",
+        },
+        "type": "**",
+      },
+      "kind": "expressionstatement",
+    },
+  ],
+  "errors": Array [],
+  "kind": "program",
+}
+`;
+
 exports[`bin + 1`] = `
 Program {
   "children": Array [
@@ -567,25 +602,25 @@ Program {
     ExpressionStatement {
       "expression": Bin {
         "kind": "bin",
-        "left": Bin {
+        "left": Variable {
+          "curly": false,
+          "kind": "variable",
+          "name": "a",
+        },
+        "right": Bin {
           "kind": "bin",
           "left": Variable {
             "curly": false,
             "kind": "variable",
-            "name": "foo",
+            "name": "b",
           },
           "right": Variable {
             "curly": false,
             "kind": "variable",
-            "name": "bar",
+            "name": "c",
           },
           "type": "??",
         },
-        "right": Variable {
-          "curly": false,
-          "kind": "variable",
-          "name": "bazz",
-        },
         "type": "??",
       },
       "kind": "expressionstatement",

test/snapshot/bin.test.js

@@ -103,8 +103,11 @@ describe("bin", () => {
   it("??", () => {
     expect(parser.parseEval("$foo ?? $bar;")).toMatchSnapshot();
   });
+  it("** right-associative", () => {
+    expect(parser.parseEval("$a ** $b ** $c;")).toMatchSnapshot();
+  });
   it("?? right-associative", () => {
-    expect(parser.parseEval("$foo ?? $bar ?? $bazz;")).toMatchSnapshot();
+    expect(parser.parseEval("$a ?? $b ?? $c;")).toMatchSnapshot();
   });
   it("?? (php < 7)", function() {
     const astErr = parser.parseEval(`$var ?? $var;`, {