initial checkin of SkSL compiler

src/sksl/SkSLParser.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_PARSER
+#define SKSL_PARSER
+
+#include <string>
+#include <vector>
+#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 ASTLayout;
+struct ASTModifiers;
+struct ASTParameter;
+struct ASTReturnStatement;
+struct ASTStatement;
+struct ASTSuffix;
+struct ASTType;
+struct ASTWhileStatement;
+struct ASTVarDeclaration;
+class SymbolTable;
+
+/**
+ * Consumes .sksl text and produces an abstract syntax tree describing the contents.
+ */
+class Parser {
+public:
+    Parser(std::string text, std::shared_ptr<SymbolTable> types, ErrorReporter& errors);

[dogben, 2016/06/21 17:53:48]

nit: Would "const std::string& text" work here?

nit: In what circumstances would the caller have SymbolTable go out of scope
before Parser? (If never, it seems like raw pointer (or reference, if you
prefer) would make more sense than shared_ptr.)

+
+    ~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();
+
+    // 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> directive();
+
+    void precision();
+
+    std::unique_ptr<ASTDeclaration> declaration();
+
+    std::unique_ptr<ASTType> type();
+
+    std::unique_ptr<ASTParameter> parameter();
+
+    ASTLayout layout();
+
+    ASTModifiers modifiers();
+
+    std::unique_ptr<ASTStatement> statement();
+
+    std::unique_ptr<ASTType> structDeclaration();
+
+    std::unique_ptr<ASTVarDeclaration> varDeclaration();
+
+    std::unique_ptr<ASTDeclaration> interfaceBlock(ASTModifiers mods);
+
+    std::unique_ptr<ASTIfStatement> ifStatement();
+
+    std::unique_ptr<ASTWhileStatement> whileStatement();
+
+    std::unique_ptr<ASTDoStatement> doStatement();
+
+    std::unique_ptr<ASTForStatement> forStatement();
+
+    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(std::string* dest);
+
+    std::unique_ptr<ASTVarDeclaration> varDeclarationEnd(ASTModifiers modifiers,
+                                                         std::unique_ptr<ASTType> type, 
+                                                         std::string name);
+
+    /**
+     * 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()).

[dogben, 2016/06/21 17:53:48]

nit: Maybe also note that you can't call pushback after peek?

+     */
+    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, std::string expected, Token* result = nullptr);
+
+    void error(Position p, std::string msg);
+    
+    /**
+     * Returns true if the 'name' identifier refers to a type name. For instance, isType("int") will
+     * always return true.
+     */
+    bool isType(std::string name);
+
+    void* fScanner;

[dogben, 2016/06/21 17:53:48]

nit: Any reason not to make fields and helper methods private?

+    YY_BUFFER_STATE fBuffer;
+    Token fPushback;
+    std::shared_ptr<SymbolTable> fTypes;
+    ErrorReporter& fErrors;
+};
+
+} // namespace
+
+#endif