Merge pull request #32 from xp-framework/feature/new-callable

Support `new T(...)` callable syntax

src/main/php/lang/ast/nodes/CallableNewExpression.class.php

@@ -0,0 +1,16 @@
+<?php namespace lang\ast\nodes;
+
+use lang\ast\Node;
+
+class CallableNewExpression extends Node {
+  public $kind= 'callablenew';
+  public $type;
+
+  public function __construct($type, $line= -1) {
+    $this->type= $type;
+    $this->line= $line;
+  }
+
+  /** @return iterable */
+  public function children() { return [$this->type]; }
+}

src/main/php/lang/ast/syntax/PHP.class.php

@@ -6,6 +6,7 @@
   Braced,
   BreakStatement,
   CallableExpression,
+  CallableNewExpression,
   CaseLabel,
   CastExpression,
   CatchStatement,
@@ -321,6 +322,30 @@ public function __construct() {
       }
 
       $parse->expecting('(', 'new arguments');
+
+      // Resolve ambiguity by looking ahead: `new T(...)` which is a first-class
+      // callable reference vs. `new T(...$it)` - a call with an unpacked argument
+      if ('...' === $parse->token->value) {
+        $dots= $parse->token;
+        $parse->forward();
+        if (')' === $parse->token->value) {
+          $parse->forward();
+
+          if (null === $type) {
+            $class= $this->clazz($parse, null);
+            $class->annotations= $annotations;
+            $new= new NewClassExpression($class, null, $token->line);
+          } else {
+            $new= new NewExpression($type, null, $token->line);
+          }
+
+          return new CallableNewExpression($new, $token->line);
+        }
+
+        $parse->queue[]= $parse->token;
+        $parse->token= $dots;
+      }
+
       $arguments= $this->arguments($parse);
       $parse->expecting(')', 'new arguments');
 

src/test/php/lang/ast/unittest/parse/InvokeTest.class.php

@@ -1,6 +1,16 @@
 <?php namespace lang\ast\unittest\parse;
 
-use lang\ast\nodes\{CallableExpression, InstanceExpression, InvokeExpression, UnpackExpression, ScopeExpression, Literal, Variable};
+use lang\ast\nodes\{
+  CallableExpression,
+  CallableNewExpression,
+  NewExpression,
+  InstanceExpression,
+  InvokeExpression,
+  UnpackExpression,
+  ScopeExpression,
+  Literal,
+  Variable
+};
 use unittest\{Assert, Test};
 
 /**
@@ -87,4 +97,12 @@ public function first_class_callable_static() {
       'self::length(...);'
     );
   }
+
+  #[Test]
+  public function first_class_callable_object_creation() {
+    $this->assertParsed(
+      [new CallableNewExpression(new NewExpression('\\T', null, self::LINE), self::LINE)],
+      'new T(...);'
+    );
+  }
 }