initial checkin of SkSL compiler

src/sksl/ast/SkSLASTForStatement.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_ASTFORSTATEMENT
+#define SKSL_ASTFORSTATEMENT
+
+#include "SkSLASTStatement.h"
+
+namespace SkSL {
+
+/**
+ * A 'for' loop. 
+ */
+struct ASTForStatement : public ASTStatement {
+    ASTForStatement(Position position, std::unique_ptr<ASTStatement> initializer, 
+                   std::unique_ptr<ASTExpression> test, std::unique_ptr<ASTExpression> next,
+                   std::unique_ptr<ASTStatement> statement)
+    : INHERITED(position, kFor_Kind)
+    , fInitializer(std::move(initializer))
+    , fTest(std::move(test))
+    , fNext(std::move(next))
+    , fStatement(std::move(statement)) {}
+
+    std::string description() const override {
+        std::string result = "for (";
+        if (fInitializer) {
+            result.append(fInitializer->description());
+        }
+        result += " ";
+        if (fTest) {
+            result.append(fTest->description());
+        }
+        result += "; ";
+        if (fNext) {
+            result.append(fNext->description());
+        }
+        result += ") ";
+        result += fStatement->description();
+        return result;
+    }
+
+    const std::unique_ptr<ASTStatement> fInitializer;
+    const std::unique_ptr<ASTExpression> fTest;
+    const std::unique_ptr<ASTExpression> fNext;
+    const std::unique_ptr<ASTStatement> fStatement;
+
+    typedef ASTStatement INHERITED;
+};
+
+} // namespace
+
+#endif