first pass at implementing match expression

Author: cseufert

src/ast.js

@@ -486,6 +486,7 @@ AST.prototype.checkNodes = function () {
   require("./ast/declaration"),
   require("./ast/declare"),
   require("./ast/declaredirective"),
+  require("./ast/defaultkeyword"),
   require("./ast/do"),
   require("./ast/echo"),
   require("./ast/empty"),
@@ -514,6 +515,7 @@ AST.prototype.checkNodes = function () {
   require("./ast/literal"),
   require("./ast/lookup"),
   require("./ast/magic"),
+  require("./ast/match"),
   require("./ast/method"),
   require("./ast/name"),
   require("./ast/namespace"),

src/ast/defaultkeyword.js

@@ -0,0 +1,23 @@
+/**
+ * Copyright (C) 2018 Glayzzle (BSD3 License)
+ * @authors https://github.com/glayzzle/php-parser/graphs/contributors
+ * @url http://glayzzle.com
+ */
+"use strict";
+
+const Node = require("./node");
+const KIND = "defaultkeyword";
+
+/**
+ * Represents the null keyword
+ * @constructor NullKeyword
+ * @extends {Node}
+ */
+module.exports = Node.extends(KIND, function DefaultKeyword(
+  raw,
+  docs,
+  location
+) {
+  Node.apply(this, [KIND, docs, location]);
+  this.raw = raw;
+});

src/ast/match.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright (C) 2018 Glayzzle (BSD3 License)
+ * @authors https://github.com/glayzzle/php-parser/graphs/contributors
+ * @url http://glayzzle.com
+ */
+"use strict";
+
+const Expression = require("./expression");
+const KIND = "match";
+
+/**
+ * Defines a match expression
+ * @constructor Match
+ * @extends {Expression}
+ * @property {Expression} test
+ * @property {Block} body
+ * @property {boolean} shortForm
+ */
+module.exports = Expression.extends(KIND, function Match(
+  test,
+  body,
+  docs,
+  location
+) {
+  Expression.apply(this, [KIND, docs, location]);
+  this.test = test;
+  this.body = body;
+});

src/lexer.js

@@ -106,6 +106,7 @@ const lexer = function (engine) {
     or: this.tok.T_LOGICAL_OR,
     and: this.tok.T_LOGICAL_AND,
     xor: this.tok.T_LOGICAL_XOR,
+    match: this.tok.T_MATCH,
   };
   this.castKeywords = {
     int: this.tok.T_INT_CAST,

src/parser.js

@@ -96,6 +96,7 @@ const parser = function (lexer, ast) {
         this.tok.T_LOGICAL_AND,
         this.tok.T_LOGICAL_OR,
         this.tok.T_LOGICAL_XOR,
+        this.tok.T_MATCH,
         this.tok.T_METHOD_C,
         this.tok.T_NAMESPACE,
         this.tok.T_NEW,
@@ -192,6 +193,7 @@ const parser = function (lexer, ast) {
         this.tok.T_NEW,
         this.tok.T_ISSET,
         this.tok.T_EMPTY,
+        this.tok.T_MATCH,
         this.tok.T_INCLUDE,
         this.tok.T_INCLUDE_ONCE,
         this.tok.T_REQUIRE,

src/parser/expr.js

@@ -320,6 +320,9 @@ module.exports = {
       case this.tok.T_REQUIRE:
       case this.tok.T_REQUIRE_ONCE:
         return this.read_internal_functions_in_yacc();
+
+      case this.tok.T_MATCH:
+        return this.read_match_statement();
       case this.tok.T_INT_CAST:
         return this.read_expr_cast("int");
 
@@ -602,6 +605,53 @@ module.exports = {
     );
   },
 
+  read_match_statement: function () {
+    const node = this.node("match");
+    this.expect(this.tok.T_MATCH) && this.next();
+    if (!this.version >= 800) {
+      this.reaseError("Match statements are not allowed");
+    }
+    let source = null;
+    let body = null;
+    if (this.expect("(")) this.next();
+    source = this.read_expr();
+    if (this.expect(")")) this.next();
+    if (this.expect("{")) this.next();
+    body = this.read_match_list();
+    if (this.expect("}")) this.next();
+    return node(source, body);
+  },
+
+  read_match_list: function () {
+    return this.read_list(() => this.read_match_pair(), ",", true);
+  },
+
+  read_match_pair: function () {
+    if (this.token === "}") {
+      return;
+    }
+
+    if (this.token === ",") {
+      return this.node("noop")();
+    }
+
+    const entry = this.node("entry");
+
+    let key = null;
+    if (this.token === this.tok.T_DEFAULT) {
+      key = this.node("defaultkeyword")("default");
+      this.next();
+    } else {
+      key = this.read_expr();
+    }
+    if (this.expect(this.tok.T_DOUBLE_ARROW)) {
+      this.next();
+    }
+    const value = this.read_expr();
+
+    return entry(key, value, false, false);
+  },
+
   /**
    * ```ebnf
    *    new_expr ::= T_NEW (namespace_name function_argument_list) | (T_CLASS ... class declaration)

src/tokens.js

@@ -147,6 +147,7 @@ module.exports = {
     234: "T_COALESCE_EQUAL",
     235: "T_FN",
     236: "T_NULLSAFE_OBJECT_OPERATOR",
+    237: "T_MATCH",
   },
   names: {
     T_HALT_COMPILER: 101,
@@ -285,5 +286,6 @@ module.exports = {
     T_COALESCE_EQUAL: 234,
     T_FN: 235,
     T_NULLSAFE_OBJECT_OPERATOR: 236,
+    T_MATCH: 237,
   },
 };

test/snapshot/match.test.js

@@ -0,0 +1,15 @@
+const parser = require("../main");
+
+describe("match", () => {
+  it("can be parsed", () => {
+    const ast = parser.parseEval(`
+    $test = match($a) {
+    true => 'yes',
+    false => 'no',
+    default => null,
+    };
+    `);
+    console.log(ast.children[0].expression.right.body);
+    // expect (ast).toMatchSnapshot();
+  });
+});