Implement trait method aliasing

Author: thekid

src/main/php/lang/ast/Emitter.class.php

@@ -376,7 +376,16 @@ protected function emitTrait($node) {
   }
 
   protected function emitUse($node) {
-    $this->out->write('use '.$node->value.';');
+    $this->out->write('use '.implode(',', $node->value[0]));
+    if ($node->value[1]) {
+      $this->out->write('{');
+      foreach ($node->value[1] as $reference => $alias) {
+        $this->out->write($reference.' as '.$alias.';');
+      }
+      $this->out->write('}');
+    } else {
+      $this->out->write(';');
+    }
   }
 
   protected function emitConst($node) {

src/main/php/lang/ast/Parse.class.php

@@ -963,11 +963,44 @@ private function body() {
       } else if ('use' === $this->token->symbol->id) {
         $member= new Node($this->token->symbol);
         $member->arity= 'use';
+
         $this->token= $this->advance();
-        $member->value= $this->scope->resolve($this->token->value);
+        $types= [];
+        do {
+          $types[]= $this->scope->resolve($this->token->value);
+          $this->token= $this->advance();
+          if (',' === $this->token->value) {
+            $this->token= $this->advance();
+            continue;
+          } else {
+            break;
+          }
+        } while ($this->token->value);
+
+        $aliases= [];
+        if ('{' === $this->token->value) {
+          $this->token= $this->advance();
+          while ('}' !== $this->token->value) {
+            $method= $this->token->value;
+            $this->token= $this->advance();
+            if ('::' === $this->token->value) {
+              $this->token= $this->advance();
+              $method= $this->scope->resolve($method).'::'.$this->token->value;
+              $this->token= $this->advance();
+            }
+            $this->token= $this->expect('as');
+            $alias= $this->token->value;
+            $this->token= $this->advance();
+            $this->token= $this->expect(';');
+            $aliases[$method]= $alias;
+          }
+          $this->token= $this->expect('}');
+        } else {
+          $this->token= $this->expect(';');
+        }
+
+        $member->value= [$types, $aliases];
         $body[]= $member;
-        $this->token= $this->advance();
-        $this->token= $this->expect(';');
       } else if ('function' === $this->token->symbol->id) {
         $member= new Node($this->token->symbol);
         $member->arity= 'method';

src/test/php/lang/ast/unittest/emit/TraitsTest.class.php

@@ -5,6 +5,7 @@
 /**
  * Traits
  *
+ * @see   http://php.net/traits
  * @see   https://wiki.php.net/rfc/horizontalreuse
  */
 class TraitsTest extends EmittingTest {
@@ -20,4 +21,30 @@ public function trait_method_is_part_of_type() {
     $t= $this->type('class <T> { use \lang\ast\unittest\emit\Loading; }');
     $this->assertTrue($t->hasMethod('loaded'));
   }
+
+  #[@test]
+  public function trait_is_resolved() {
+    $t= $this->type('use lang\ast\unittest\emit\Loading; class <T> { use Loading; }');
+    $this->assertEquals([new XPClass(Loading::class)], $t->getTraits());
+  }
+
+  #[@test]
+  public function trait_method_aliased() {
+    $t= $this->type('use lang\ast\unittest\emit\Loading; class <T> {
+      use Loading {
+        loaded as hasLoaded;
+      }
+    }');
+    $this->assertTrue($t->hasMethod('hasLoaded'));
+  }
+
+  #[@test]
+  public function trait_method_aliased_qualified() {
+    $t= $this->type('use lang\ast\unittest\emit\Loading; class <T> {
+      use Loading {
+        Loading::loaded as hasLoaded;
+      }
+    }');
+    $this->assertTrue($t->hasMethod('hasLoaded'));
+  }
 }

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

@@ -85,19 +85,27 @@ public function empty_trait() {
   #[@test]
   public function class_with_trait() {
     $this->assertNodes(
-      [['class' => ['\\A', [], null, [], [['use' => '\\B']], []]]],
+      [['class' => ['\\A', [], null, [], [['use' => [['\\B'], []]]], []]]],
       $this->parse('class A { use B; }')
     );
   }
 
   #[@test]
-  public function class_with_traits() {
+  public function class_with_multiple_traits() {
     $this->assertNodes(
-      [['class' => ['\\A', [], null, [], [['use' => '\\B'], ['use' => '\\C']], []]]],
+      [['class' => ['\\A', [], null, [], [['use' => [['\\B'], []]], ['use' => [['\\C'], []]]], []]]],
       $this->parse('class A { use B; use C; }')
     );
   }
 
+  #[@test]
+  public function class_with_comma_separated_traits() {
+    $this->assertNodes(
+      [['class' => ['\\A', [], null, [], [['use' => [['\\B', '\\C'], []]]], []]]],
+      $this->parse('class A { use B, C; }')
+    );
+  }
+
   #[@test]
   public function class_in_namespace() {
     $this->assertNodes(