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/*
* 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_PARSER
#define SKSL_PARSER
#include <vector>
#include <memory>
#include <unordered_map>
#include <unordered_set>
#include "SkSLErrorReporter.h"
#include "SkSLToken.h"
struct yy_buffer_state;
#define YY_TYPEDEF_YY_BUFFER_STATE
typedef struct yy_buffer_state *YY_BUFFER_STATE;
namespace SkSL {
struct ASTBlock;
struct ASTBreakStatement;
struct ASTContinueStatement;
struct ASTDeclaration;
struct ASTDiscardStatement;
struct ASTDoStatement;
struct ASTExpression;
struct ASTExpressionStatement;
struct ASTForStatement;
struct ASTIfStatement;
struct ASTInterfaceBlock;
struct ASTParameter;
struct ASTPrecision;
struct ASTReturnStatement;
struct ASTStatement;
struct ASTSuffix;
struct ASTSwitchCase;
struct ASTSwitchStatement;
struct ASTType;
struct ASTWhileStatement;
struct ASTVarDeclarations;
struct Layout;
struct Modifiers;
class SymbolTable;
/**
* Consumes .sksl text and produces an abstract syntax tree describing the contents.
*/
class Parser {
public:
Parser(SkString text, SymbolTable& types, ErrorReporter& errors);
~Parser();
/**
* Consumes a complete .sksl file and produces a list of declarations. Errors are reported via
* the ErrorReporter; the return value may contain some declarations even when errors have
* occurred.
*/
std::vector<std::unique_ptr<ASTDeclaration>> file();
private:
/**
* Return the next token from the parse stream.
*/
Token nextToken();
/**
* Push a token back onto the parse stream, so that it is the next one read. Only a single level
* of pushback is supported (that is, it is an error to call pushback() twice in a row without
* an intervening nextToken()).
*/
void pushback(Token t);
/**
* Returns the next token without consuming it from the stream.
*/
Token peek();
/**
* Reads the next token and generates an error if it is not the expected type. The 'expected'
* string is part of the error message, which reads:
*
* "expected <expected>, but found '<actual text>'"
*
* If 'result' is non-null, it is set to point to the token that was read.
* Returns true if the read token was as expected, false otherwise.
*/
bool expect(Token::Kind kind, const char* expected, Token* result = nullptr);
bool expect(Token::Kind kind, SkString expected, Token* result = nullptr);
void error(Position p, const char* msg);
void error(Position p, SkString msg);
/**
* Returns true if the 'name' identifier refers to a type name. For instance, isType("int") will
* always return true.
*/
bool isType(SkString name);
// these functions parse individual grammar rules from the current parse position; you probably
// don't need to call any of these outside of the parser. The function declarations in the .cpp
// file have comments describing the grammar rules.
std::unique_ptr<ASTDeclaration> precision();
std::unique_ptr<ASTDeclaration> directive();
std::unique_ptr<ASTDeclaration> declaration();
std::unique_ptr<ASTVarDeclarations> varDeclarations();
std::unique_ptr<ASTType> structDeclaration();
std::unique_ptr<ASTVarDeclarations> structVarDeclaration(Modifiers modifiers);
std::unique_ptr<ASTVarDeclarations> varDeclarationEnd(Modifiers modifiers,
std::unique_ptr<ASTType> type,
SkString name);
std::unique_ptr<ASTParameter> parameter();
int layoutInt();
Layout layout();
Modifiers modifiers();
Modifiers modifiersWithDefaults(int defaultFlags);
std::unique_ptr<ASTStatement> statement();
std::unique_ptr<ASTType> type();
std::unique_ptr<ASTDeclaration> interfaceBlock(Modifiers mods);
std::unique_ptr<ASTIfStatement> ifStatement();
std::unique_ptr<ASTDoStatement> doStatement();
std::unique_ptr<ASTWhileStatement> whileStatement();
std::unique_ptr<ASTForStatement> forStatement();
std::unique_ptr<ASTSwitchCase> switchCase();
std::unique_ptr<ASTStatement> switchStatement();
std::unique_ptr<ASTReturnStatement> returnStatement();
std::unique_ptr<ASTBreakStatement> breakStatement();
std::unique_ptr<ASTContinueStatement> continueStatement();
std::unique_ptr<ASTDiscardStatement> discardStatement();
std::unique_ptr<ASTBlock> block();
std::unique_ptr<ASTExpressionStatement> expressionStatement();
std::unique_ptr<ASTExpression> expression();
std::unique_ptr<ASTExpression> assignmentExpression();
std::unique_ptr<ASTExpression> ternaryExpression();
std::unique_ptr<ASTExpression> logicalOrExpression();
std::unique_ptr<ASTExpression> logicalXorExpression();
std::unique_ptr<ASTExpression> logicalAndExpression();
std::unique_ptr<ASTExpression> bitwiseOrExpression();
std::unique_ptr<ASTExpression> bitwiseXorExpression();
std::unique_ptr<ASTExpression> bitwiseAndExpression();
std::unique_ptr<ASTExpression> equalityExpression();
std::unique_ptr<ASTExpression> relationalExpression();
std::unique_ptr<ASTExpression> shiftExpression();
std::unique_ptr<ASTExpression> additiveExpression();
std::unique_ptr<ASTExpression> multiplicativeExpression();
std::unique_ptr<ASTExpression> unaryExpression();
std::unique_ptr<ASTExpression> postfixExpression();
std::unique_ptr<ASTSuffix> suffix();
std::unique_ptr<ASTExpression> term();
bool intLiteral(int64_t* dest);
bool floatLiteral(double* dest);
bool boolLiteral(bool* dest);
bool identifier(SkString* dest);
void* fScanner;
void* fLayoutScanner;
YY_BUFFER_STATE fBuffer;
// current parse depth, used to enforce a recursion limit to try to keep us from overflowing the
// stack on pathological inputs
int fDepth = 0;
Token fPushback;
SymbolTable& fTypes;
ErrorReporter& fErrors;
friend class AutoDepth;
};
} // namespace
#endif
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