initial checkin of SkSL compiler

src/sksl/ast/SkSLASTSuffix.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_ASTSUFFIX
+#define SKSL_ASTSUFFIX
+
+#include "SkSLASTPositionNode.h"
+#include "SkSLASTExpression.h"
+
+namespace SkSL {
+
+/**
+ * This and its subclasses represents expression suffixes, such as '[0]' or '.rgb'. Suffixes are not
+ * expressions in and of themselves; they are attached to expressions to modify them.
+ */
+struct ASTSuffix : public ASTPositionNode {
+    enum Kind {
+        kIndex_Kind,
+        kCall_Kind,
+        kField_Kind,
+        kPostIncrement_Kind,
+        kPostDecrement_Kind
+    };
+
+    ASTSuffix(Position position, Kind kind)
+    : INHERITED(position)
+    , fKind(kind) {}
+
+    std::string description() const override {
+        switch (fKind) {
+            case kPostIncrement_Kind:
+                return "++";
+            case kPostDecrement_Kind:
+                return "--";
+            default:
+                ABORT("unsupported suffix operator");
+        }        
+    }
+
+    Kind fKind;
+
+    typedef ASTPositionNode INHERITED;
+};
+
+} // namespace
+
+#endif