Files
carbon-lang/executable_semantics/syntax/parse.cpp
T
Dave Abrahams 436a9dda79 [executable semantics] Minimal cxx parser (#363)
Makes a minimal transition to using C++ in the parser.
2021-03-09 20:46:52 -08:00

46 lines
1.3 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "executable_semantics/syntax/parse.h"
#include <iostream>
#include "executable_semantics/syntax/parse_and_lex_context.h"
#include "executable_semantics/syntax/parser.h"
#include "executable_semantics/tracing_flag.h"
extern FILE* yyin;
namespace Carbon {
// Returns an abstract representation of the program contained in the
// well-formed input file, or if the file was malformed, a description of the
// problem.
auto parse(const std::string& inputFileName)
-> std::variant<AST, SyntaxErrorCode> {
yyin = fopen(inputFileName.c_str(), "r");
if (yyin == nullptr) {
std::cerr << "Error opening '" << inputFileName
<< "': " << std::strerror(errno) << std::endl;
exit(1);
}
std::optional<AST> parsedInput = std::nullopt;
ParseAndLexContext context(inputFileName);
auto syntaxErrorCode = yy::parser(parsedInput, context)();
if (syntaxErrorCode != 0) {
return syntaxErrorCode;
}
if (parsedInput == std::nullopt) {
std::cerr << "Internal error: parser validated syntax yet didn't produce "
"an AST.\n";
exit(1);
}
return *parsedInput;
}
} // namespace Carbon