| // Copyright 2018 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #pragma once |
| |
| #include <memory> |
| #include <vector> |
| |
| #include "garnet/bin/zxdb/common/err.h" |
| #include "garnet/bin/zxdb/expr/expr_node.h" |
| #include "garnet/bin/zxdb/expr/expr_token.h" |
| |
| namespace zxdb { |
| |
| class ExprParser { |
| public: |
| ExprParser(std::vector<ExprToken> tokens); |
| |
| // Returns the root expression node on successful parsing. On error, returns |
| // an empty pointer in which case the error message can be read from err() |
| // ad error_token() |
| fxl::RefPtr<ExprNode> Parse(); |
| |
| // The result of parsing. Since this does not have access to the initial |
| // string, it will not indicate context for the error. That can be generated |
| // from the error_token() if desired. |
| const Err& err() const { return err_; } |
| |
| ExprToken error_token() const { return error_token_; } |
| |
| private: |
| struct DispatchInfo; |
| |
| // When recursively calling this function, call with the same precedence as |
| // the current expression for left-associativity (operators evaluated from |
| // left-to-right), and one less for right-associativity. |
| fxl::RefPtr<ExprNode> ParseExpression(int precedence); |
| |
| // Parses template parameter lists. The "stop_before" parameter indicates how |
| // the list is expected to end (i.e. ">"). Sets the error on failure. |
| std::vector<std::string> ParseTemplateList(ExprToken::Type stop_before); |
| |
| fxl::RefPtr<ExprNode> AmpersandPrefix(const ExprToken& token); |
| fxl::RefPtr<ExprNode> BinaryOpInfix(fxl::RefPtr<ExprNode> left, |
| const ExprToken& token); |
| fxl::RefPtr<ExprNode> ScopeInfix(fxl::RefPtr<ExprNode> left, |
| const ExprToken& token); |
| fxl::RefPtr<ExprNode> ScopePrefix(const ExprToken& token); |
| fxl::RefPtr<ExprNode> DotOrArrowInfix(fxl::RefPtr<ExprNode> left, |
| const ExprToken& token); |
| fxl::RefPtr<ExprNode> IntegerPrefix(const ExprToken& token); |
| fxl::RefPtr<ExprNode> LeftParenPrefix(const ExprToken& token); |
| fxl::RefPtr<ExprNode> LeftSquareInfix(fxl::RefPtr<ExprNode> left, |
| const ExprToken& token); |
| fxl::RefPtr<ExprNode> LessInfix(fxl::RefPtr<ExprNode> left, |
| const ExprToken& token); |
| fxl::RefPtr<ExprNode> GreaterInfix(fxl::RefPtr<ExprNode> left, |
| const ExprToken& token); |
| fxl::RefPtr<ExprNode> MinusPrefix(const ExprToken& token); |
| fxl::RefPtr<ExprNode> NamePrefix(const ExprToken& token); |
| fxl::RefPtr<ExprNode> NameInfix(fxl::RefPtr<ExprNode> left, |
| const ExprToken& token); |
| fxl::RefPtr<ExprNode> StarPrefix(const ExprToken& token); |
| |
| // Returns true if the next token is the given type. |
| bool LookAhead(ExprToken::Type type) const; |
| |
| // Returns the next token or the invalid token if nothing is left. Advances |
| // to the next token. |
| const ExprToken& Consume(); |
| |
| // Consumes a token of the given type, returning it if there was one |
| // available and the type matches. Otherwise, sets the error condition using |
| // the given error_token and message, and returns a reference to an invalid |
| // token. It will advance to the next token. |
| const ExprToken& Consume(ExprToken::Type type, const ExprToken& error_token, |
| const char* error_msg); |
| |
| // Joins two IdentifierExprNodes. The |left| can be null which will prepend |
| // the scope token to the right (generating a fully-qualified identifier). |
| // Otherwise, right is null-checked and both are checked that they're |
| // identifiers. |
| fxl::RefPtr<ExprNode> JoinIdentifiers(fxl::RefPtr<ExprNode> left, |
| const ExprToken& scope_token, |
| fxl::RefPtr<ExprNode> right); |
| |
| void SetError(const ExprToken& token, std::string msg); |
| |
| // Call this only if !at_end(). |
| const ExprToken& cur_token() const { return tokens_[cur_]; } |
| |
| bool has_error() const { return err_.has_error(); } |
| bool at_end() const { return cur_ == tokens_.size(); } |
| |
| static DispatchInfo kDispatchInfo[]; |
| |
| std::vector<ExprToken> tokens_; |
| size_t cur_ = 0; // Current index into tokens_. |
| |
| // On error, the message and token where an error was encountered. |
| Err err_; |
| ExprToken error_token_; |
| |
| // This is a kInvalid token that we can return in error cases without having |
| // to reference something in the tokens_ array. |
| static const ExprToken kInvalidToken; |
| }; |
| |
| } // namespace zxdb |