Add support for class Name Resolution As Scalar Via "class" Keyword

src/main/jay/grammars/php.jay

@@ -40,7 +40,7 @@ use xp\compiler\ast\MemberAccessNode;
 use xp\compiler\ast\StaticMemberAccessNode;
 use xp\compiler\ast\ConstantNode;
 use xp\compiler\ast\ConstantAccessNode;
-use xp\compiler\ast\ClassAccessNode;
+use xp\compiler\ast\ClassNameAccessNode;
 use xp\compiler\ast\IntegerNode;
 use xp\compiler\ast\HexNode;
 use xp\compiler\ast\OctalNode;
@@ -379,6 +379,9 @@ annotationvalue:
   | qualifiedname T_DOUBLE_COLON T_VARIABLE {
       $$= $yyLex->create(new StaticMemberAccessNode(new TypeName($1), $3));
     }
+  | qualifiedname T_DOUBLE_COLON T_CLASS {
+      $$= $yyLex->create(new ClassNameAccessNode(new TypeName($1)));
+    }
 ;
 
 
@@ -559,6 +562,9 @@ staticmember:
   | T_WORD {
       $$= new ConstantAccessNode(NULL, $1);
     }
+  | T_CLASS {
+      $$= new ClassNameAccessNode(NULL);
+    }
 ;
 
 expression:

src/main/php/xp/compiler/ast/ClassNameAccessNode.class.php

@@ -0,0 +1,21 @@
+<?php namespace xp\compiler\ast;
+
+/**
+ * Represents class name access
+ *
+ * ```php
+ * self::class;
+ * ```
+ */
+class ClassNameAccessNode extends Node {
+  public $type= null;
+
+  /**
+   * Constructor
+   *
+   * @param   xp.compiler.types.TypeName type
+   */
+  public function __construct($type= null) {
+    $this->type= $type;
+  }
+}

src/main/php/xp/compiler/emit/Emitter.class.php

@@ -314,6 +314,14 @@ protected abstract function emitConstantAccess($b, $access);
    */
   protected abstract function emitClassAccess($b, $access);
 
+  /**
+   * Emit class name access
+   *
+   * @param   xp.compiler.emit.Buffer b
+   * @param   xp.compiler.ast.ClassNameAccessNode access
+   */
+  protected abstract function emitClassNameAccess($b, $access);
+
   /**
    * Emit a braced expression
    *

src/main/php/xp/compiler/emit/php/Emitter.class.php

@@ -685,6 +685,17 @@ public function emitClassAccess($b, $access) {
     $this->scope[0]->setType($access, $classType);
   }
 
+  /**
+   * Emit class name access
+   *
+   * @param   xp.compiler.emit.Buffer b
+   * @param   xp.compiler.ast.ClassNameAccessNode access
+   */
+  public function emitClassNameAccess($b, $access) {
+    $b->append("'")->append(substr($this->literal($this->resolveType($access->type)), 1))->append("'");
+    $this->scope[0]->setType($access, new TypeName('string'));
+  }
+
   /**
    * Emit a braced expression
    *