| // Copyright 2020 The Tint Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef SRC_TINT_READER_WGSL_LEXER_H_ |
| #define SRC_TINT_READER_WGSL_LEXER_H_ |
| |
| #include <string> |
| |
| #include "src/tint/reader/wgsl/token.h" |
| |
| namespace tint::reader::wgsl { |
| |
| /// Converts the input stream into a series of Tokens |
| class Lexer { |
| public: |
| /// Creates a new Lexer |
| /// @param file the source file |
| explicit Lexer(const Source::File* file); |
| ~Lexer(); |
| |
| /// Returns the next token in the input stream. |
| /// @return Token |
| Token next(); |
| |
| private: |
| /// Advances past blankspace and comments, if present at the current position. |
| /// @returns error token, EOF, or uninitialized |
| Token skip_blankspace_and_comments(); |
| /// Advances past a comment at the current position, if one exists. |
| /// Returns an error if there was an unterminated block comment, |
| /// or a null character was present. |
| /// @returns uninitialized token on success, or error |
| Token skip_comment(); |
| |
| Token build_token_from_int_if_possible(Source source, size_t start, int32_t base); |
| |
| Token check_keyword(const Source&, std::string_view); |
| |
| /// The try_* methods have the following in common: |
| /// - They assume there is at least one character to be consumed, |
| /// i.e. the input has not yet reached end of file. |
| /// - They return an initialized token when they match and consume |
| /// a token of the specified kind. |
| /// - Some can return an error token. |
| /// - Otherwise they return an uninitialized token when they did not |
| /// match a token of the specfied kind. |
| Token try_float(); |
| Token try_hex_float(); |
| Token try_hex_integer(); |
| Token try_ident(); |
| Token try_integer(); |
| Token try_punctuation(); |
| |
| Source begin_source() const; |
| void end_source(Source&) const; |
| |
| /// @returns view of current line |
| const std::string_view line() const; |
| /// @returns position in current line |
| size_t pos() const; |
| /// @returns length of current line |
| size_t length() const; |
| /// @returns reference to character at `pos` within current line |
| const char& at(size_t pos) const; |
| /// @returns substring view at `offset` within current line of length `count` |
| std::string_view substr(size_t offset, size_t count); |
| /// advances current position by `offset` within current line |
| void advance(size_t offset = 1); |
| /// sets current position to `pos` within current line |
| void set_pos(size_t pos); |
| /// advances current position to next line |
| void advance_line(); |
| /// @returns true if the end of the input has been reached. |
| bool is_eof() const; |
| /// @returns true if the end of the current line has been reached. |
| bool is_eol() const; |
| /// @returns true if there is another character on the input and |
| /// it is not null. |
| bool is_null() const; |
| /// @param ch a character |
| /// @returns true if 'ch' is a decimal digit |
| bool is_digit(char ch) const; |
| /// @param ch a character |
| /// @returns true if 'ch' is a hexadecimal digit |
| bool is_hex(char ch) const; |
| /// @returns true if string at `pos` matches `substr` |
| bool matches(size_t pos, std::string_view substr); |
| |
| /// The source file content |
| Source::File const* const file_; |
| /// The current location within the input |
| Source::Location location_; |
| }; |
| |
| } // namespace tint::reader::wgsl |
| |
| #endif // SRC_TINT_READER_WGSL_LEXER_H_ |