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https://github.com/carbon-language/carbon-lang.git
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Jon Meow
ed2d171703
Make the parser reentrant, working towards #769 and the ability to load other packages cleanly.
59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "executable_semantics/syntax/parse.h"
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#include "common/check.h"
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#include "executable_semantics/common/error.h"
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#include "executable_semantics/common/tracing_flag.h"
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#include "executable_semantics/syntax/lexer.h"
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#include "executable_semantics/syntax/parse_and_lex_context.h"
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#include "executable_semantics/syntax/parser.h"
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namespace Carbon {
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// Returns an abstract representation of the program contained in the
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// well-formed input file, or if the file was malformed, a description of the
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// problem.
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auto Parse(const std::string& input_file_name)
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-> std::variant<AST, SyntaxErrorCode> {
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FILE* input_file = fopen(input_file_name.c_str(), "r");
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if (input_file == nullptr) {
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FATAL_PROGRAM_ERROR_NO_LINE() << "Error opening '" << input_file_name
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<< "': " << std::strerror(errno);
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}
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// Prepare the lexer.
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yyscan_t scanner;
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yylex_init(&scanner);
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yyset_in(input_file, scanner);
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// Prepare other parser arguments.
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std::optional<AST> parsed_input = std::nullopt;
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ParseAndLexContext context(input_file_name);
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// Do the parse.
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auto parser = Parser(parsed_input, scanner, context);
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if (tracing_output) {
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parser.set_debug_level(1);
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}
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auto syntax_error_code = parser();
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// Clean up the lexer.
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fclose(input_file);
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yylex_destroy(scanner);
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// Return an error if appropriate.
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if (syntax_error_code != 0) {
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return syntax_error_code;
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}
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// Return parse results.
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CHECK(parsed_input != std::nullopt)
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<< "parser validated syntax yet didn't produce an AST.";
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return *parsed_input;
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}
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} // namespace Carbon
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