chromium/third_party/angle/src/compiler/translator/tree_util/IntermTraverse.h

//
// Copyright 2017 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// IntermTraverse.h : base classes for AST traversers that walk the AST and
//   also have the ability to transform it by replacing nodes.

#ifndef COMPILER_TRANSLATOR_TREEUTIL_INTERMTRAVERSE_H_
#define COMPILER_TRANSLATOR_TREEUTIL_INTERMTRAVERSE_H_

#include "compiler/translator/IntermNode.h"
#include "compiler/translator/tree_util/Visit.h"

namespace sh
{

class TCompiler;
class TSymbolTable;
class TSymbolUniqueId;

// For traversing the tree.  User should derive from this class overriding the visit functions,
// and then pass an object of the subclass to a traverse method of a node.
//
// The traverse*() functions may also be overridden to do other bookkeeping on the tree to provide
// contextual information to the visit functions, such as whether the node is the target of an
// assignment. This is complex to maintain and so should only be done in special cases.
//
// When using this, just fill in the methods for nodes you want visited.
// Return false from a pre-visit to skip visiting that node's subtree.
//
// See also how to write AST transformations documentation:
//   https://github.com/google/angle/blob/master/doc/WritingShaderASTTransformations.md
class TIntermTraverser : angle::NonCopyable
{ … };

// Traverser parent class that tracks where a node is a destination of a write operation and so is
// required to be an l-value.
class TLValueTrackingTraverser : public TIntermTraverser
{ … };

}  // namespace sh

#endif  // COMPILER_TRANSLATOR_TREEUTIL_INTERMTRAVERSE_H_