initial checkin of SkSL compiler

src/sksl/ast/SkSLASTIdentifier.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+ 
+#ifndef SKSL_ASTIDENTIFIER
+#define SKSL_ASTIDENTIFIER
+
+#include "SkSLASTExpression.h"
+
+namespace SkSL {
+
+/**
+ * An identifier in an expression context. 
+ */
+struct ASTIdentifier : public ASTExpression {
+    ASTIdentifier(Position position, std::string text)
+    : INHERITED(position, kIdentifier_Kind)
+    , fText(std::move(text)) {}
+
+    std::string description() const override {
+        return fText;
+    }
+
+    const std::string fText;
+
+    typedef ASTExpression INHERITED;
+};
+
+} // namespace
+
+#endif