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#include <iostream>
#include "parser.hpp"
Parser::Parser(const std::vector<Token>& tokens) : tokens_(tokens), position_(0) {}
std::unique_ptr<Program> Parser::parse() {
auto program = std::make_unique<Program>();
while (peek().type != TokenType::END_OF_FILE) {
try {
auto statement = parseStatement();
program->declarations.push_back(std::move(statement));
if (peek().type == TokenType::SEMICOLON) {
advance();
}
}
catch (const std::exception& e) {
std::cerr << " Parser error: " << e.what() << std::endl;
break;
}
}
return program;
}
std::unique_ptr<ASTNode> Parser::parseStatement() {
switch(peek().type) {
case TokenType::INT:
case TokenType::STRING:
{
return parseDeclaration();
break;
}
default:
{
error("Unexpected statement");
return nullptr;
}
}
}
std::unique_ptr<ASTNode> Parser::parseExpression() {
return parseAddSub();
}
std::unique_ptr<ASTNode> Parser::parseDeclaration() {
std::string type;
switch(peek().type) {
case TokenType::INT:
{
type = "int";
break;
}
case TokenType::STRING:
{
type = "string";
break;
}
default:
{
error("Unexpected declaration: Invalid type");
return nullptr;
}
}
advance();
std::string name = peek().value;
advance();
if (peek().type == TokenType::ASSIGN) {
advance();
auto value = parseExpression();
return std::make_unique<Declaration>(type, name, std::move(value));
}
else if (peek().type == TokenType::SEMICOLON) {
return std::make_unique<Declaration>(type, name);
}
else {
error("Invalid declaration");
return nullptr;
}
}
std::unique_ptr<ASTNode> Parser::parseAssignment() {
std::string name = peek().value;
advance();
advance(); // consume =
auto value = parseExpression();
return std::make_unique<Assignment>(name, std::move(value));
}
std::unique_ptr<ASTNode> Parser::parseAddSub() {
auto left = parseMulDiv();
while (peek().type == TokenType::PLUS || peek().type == TokenType::MINUS) {
std::string op = peek().value;
advance();
auto right = parseMulDiv();
left = std::make_unique<BinaryOp>(std::move(left), op, std::move(right));
}
return left;
}
std::unique_ptr<ASTNode> Parser::parseMulDiv() {
auto left = parsePrimary();
while (peek().type == TokenType::MULTIPLY || peek().type == TokenType::DIVIDE) {
std::string op = peek().value;
advance();
auto right = parsePrimary();
left = std::make_unique<BinaryOp>(std::move(left), op, std::move(right));
}
return left;
}
std::unique_ptr<ASTNode> Parser::parsePrimary() {
switch(peek().type) {
case TokenType::NUMBER:
{
double value = std::stod(peek().value);
advance();
return std::make_unique<NumberLiteral>(value);
}
case TokenType::IDENTIFIER:
{
std::string name = peek().value;
advance();
return std::make_unique<Identifier>(name);
}
case TokenType::STRING:
{
std::string value = peek().value;
advance();
return std::make_unique<StringLiteral>(value);
}
default:
{
error("Unknown keyword");
return nullptr;
}
}
}
Token Parser::advance() {
return tokens_[position_++];
}
Token Parser::peek() {
return tokens_[position_];
}
bool Parser::isAtEnd() {
return position_ >= tokens_.size();
}
void Parser::error(std::string s) {
}
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