initial checkin of SkSL compiler

src/sksl/ast/SkSLASTFieldSuffix.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_ASTFIELDSUFFIX
+#define SKSL_ASTFIELDSUFFIX
+
+#include "SkSLASTSuffix.h"
+
+namespace SkSL {
+
+/**
+ * A dotted identifier of the form ".foo". We refer to these as "fields" at parse time even if it is
+ * actually vector swizzle (which looks the same to the parser).
+ */
+struct ASTFieldSuffix : public ASTSuffix {
+    ASTFieldSuffix(Position position, std::string field) 
+    : INHERITED(position, ASTSuffix::kField_Kind)
+    , fField(std::move(field)) {}
+
+    std::string description() const override {
+        return "." + fField;
+    }
+
+    std::string fField;
+
+    typedef ASTSuffix INHERITED;
+};
+
+} // namespace
+
+#endif