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// 调用前端解析流程,返回语法树。
#include "frontend/AntlrDriver.h"
#include <fstream>
#include <sstream>
#include <stdexcept>
#include <string>
#include "SysYLexer.h"
#include "SysYParser.h"
#include "antlr4-runtime.h"
namespace {
class ParseErrorListener : public antlr4::BaseErrorListener {
public:
void syntaxError(antlr4::Recognizer* /*recognizer*/, antlr4::Token* /*offendingSymbol*/,
size_t line, size_t charPositionInLine,
const std::string& msg, std::exception_ptr /*e*/) override {
throw std::runtime_error("[parse] 暂不支持的语法/词法 @" + std::to_string(line) + ":" +
std::to_string(charPositionInLine) + " - " + msg);
}
};
} // namespace
AntlrResult ParseFileWithAntlr(const std::string& path) {
std::ifstream fin(path);
if (!fin.is_open()) {
throw std::runtime_error("[parse] 无法打开输入文件: " + path);
}
std::ostringstream ss;
ss << fin.rdbuf();
auto input = std::make_unique<antlr4::ANTLRInputStream>(ss.str());
auto lexer = std::make_unique<SysYLexer>(input.get());
auto tokens = std::make_unique<antlr4::CommonTokenStream>(lexer.get());
auto parser = std::make_unique<SysYParser>(tokens.get());
ParseErrorListener error_listener;
lexer->removeErrorListeners();
lexer->addErrorListener(&error_listener);
parser->removeErrorListeners();
parser->addErrorListener(&error_listener);
parser->setErrorHandler(std::make_shared<antlr4::BailErrorStrategy>());
antlr4::tree::ParseTree* tree = nullptr;
try {
tree = parser->compUnit();
} catch (const std::exception& ex) {
const std::string msg = ex.what();
if (!msg.empty()) {
throw std::runtime_error("[parse] 暂不支持的语法/词法 - " + msg);
}
if (auto* tok = parser->getCurrentToken()) {
throw std::runtime_error("[parse] 暂不支持的语法/词法 @" +
std::to_string(tok->getLine()) + ":" +
std::to_string(tok->getCharPositionInLine()) +
" near token '" + tok->getText() + "'");
}
throw std::runtime_error("[parse] 暂不支持的语法/词法");
}
AntlrResult result;
result.input = std::move(input);
result.lexer = std::move(lexer);
result.tokens = std::move(tokens);
result.parser = std::move(parser);
result.tree = tree;
return result;
}