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#include "lexer.hpp"
Lexer::Lexer(const std::string& src) : src(src), position(0), line(1), column(1) {}
std::vector<Token> Lexer::tokenise() {
while (position < src.size()) {
if (std::isdigit(src[position])) {
std::string digit;
int original_column = column;
while (std::isdigit(src[position])) {
digit.push_back(src[position]);
advance();
}
tokens.push_back(Token(TokenType::NUMBER, digit, line, original_column));
} else if (std::isalpha(src[position])) {
if (src.substr(position, 3) == "int") {
tokens.push_back(Token(TokenType::INT, "int", line, column));
for (int i=0; i<3; i++) {
advance();
}
} else if (src.substr(position, 8) == "function") {
tokens.push_back(Token(TokenType::FUNCTION, "function", line, column));
for (int i=0; i<8; i++) {
advance();
}
} else if (src.substr(position, 6) == "return") {
tokens.push_back(Token(TokenType::RETURN, "return", line, column));
for (int i=0; i<6; i++) {
advance();
}
} else if (src.substr(position, 2) == "if") {
tokens.push_back(Token(TokenType::IF, "if", line, column));
for (int i=0; i<2; i++) {
advance();
}
} else if (src.substr(position, 5) == "while") {
tokens.push_back(Token(TokenType::WHILE, "while", line, column));
for (int i=0; i<5; i++) {
advance();
}
} else if (src.substr(position, 3) == "for") {
tokens.push_back(Token(TokenType::FOR, "for", line, column));
for (int i=0; i<3; i++) {
advance();
}
} else {
std::string identifier;
int original_column = column;
while (std::isalnum(src[position])) {
identifier.push_back(src[position]);
advance();
}
tokens.push_back(Token(TokenType::IDENTIFIER, identifier, line, original_column));
}
} else if (src[position] == '+') {
tokens.push_back(Token(TokenType::PLUS, std::string(1, src[position]), line, column));
advance();
} else if (src[position] == '-') {
if (src[position + 1] == '>') {
tokens.push_back(Token(TokenType::ARROW, "->", line, column));
advance();
advance();
} else {
tokens.push_back(Token(TokenType::MINUS, std::string(1, src[position]), line, column));
advance();
}
} else if (src[position] == '*') {
tokens.push_back(Token(TokenType::MULTIPLY, std::string(1, src[position]), line, column));
advance();
} else if (src[position] == '/') {
tokens.push_back(Token(TokenType::DIVIDE, std::string(1, src[position]), line, column));
advance();
} else if (src[position] == '=') {
if (src[position + 1] == '=') {
tokens.push_back(Token(TokenType::EQUAL, "==", line, column));
advance();
advance();
} else {
tokens.push_back(Token(TokenType::ASSIGN, std::string(1, src[position]), line, column));
advance();
}
} else if (src[position] == ';') {
tokens.push_back(Token(TokenType::SEMICOLON, std::string(1, src[position]), line, column));
advance();
} else if (src[position] == '<') {
if (src[position + 1] == '=') {
tokens.push_back(Token(TokenType::LESS_EQUAL, "<=", line, column));
advance();
advance();
} else {
tokens.push_back(Token(TokenType::LESS, std::string(1, src[position]), line, column));
advance();
}
} else if (src[position] == '>') {
if (src[position + 1] == '=') {
tokens.push_back(Token(TokenType::GREATER_EQUAL, ">=", line, column));
advance();
advance();
} else {
tokens.push_back(Token(TokenType::GREATER, std::string(1, src[position]), line, column));
advance();
}
} else if (src[position] == '(') {
tokens.push_back(Token(TokenType::LEFT_BRACKET, std::string(1, src[position]), line, column));
advance();
} else if (src[position] == ')') {
tokens.push_back(Token(TokenType::RIGHT_BRACKET, std::string(1, src[position]), line, column));
advance();
} else if (src[position] == '{') {
tokens.push_back(Token(TokenType::LEFT_BRACE, std::string(1, src[position]), line, column));
advance();
} else if (src[position] == '}') {
tokens.push_back(Token(TokenType::RIGHT_BRACE, std::string(1, src[position]), line, column));
advance();
} else {
tokens.push_back(Token(TokenType::INVALID, std::string(1, src[position]), line, column));
advance();
}
skipComment();
skipWhitespace();
}
tokens.push_back(Token(TokenType::END_OF_FILE, std::string(), line, column));
return tokens;
}
char Lexer::advance() {
column++;
return src[position++];
}
void Lexer::skipWhitespace() {
while (src[position] == ' ' || src[position] == '\n') {
if (src[position] == ' ') {
position++;
column++;
} else if (src[position] == '\n') {
position++;
column = 1;
line++;
}
}
}
void Lexer::skipComment() {
if (src[position] == '/' && src[++position] == '/') {
while (src[position] != '\n') {
position++;
column++;
}
position++;
line += 1;
column = 1;
}
}
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