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lexer.cpp
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lexer.cpp
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#include <deque>
#include <iostream>
enum TokenTypes {
INTEGER,
DOUBLE,
LPAR,
RPAR,
OP2,
OP1
};
class Token {
public:
Token(std::string source, TokenTypes tType) : value(source), tokenType(tType) {}
TokenTypes getTokenType() {
return tokenType;
}
std::string getValue() {
return value;
}
std::string toString() const {
std::string str;
switch (tokenType) {
case TokenTypes::INTEGER:
str = "INTEGER";
break;
case TokenTypes::DOUBLE:
str = "DOUBLE";
break;
case TokenTypes::LPAR:
str = "LPAR";
break;
case TokenTypes::RPAR:
str = "RPAR";
break;
case TokenTypes::OP2:
str = "OP2";
break;
case TokenTypes::OP1:
str = "OP1";
break;
default:
break;
}
return value + ": " + str;
}
private:
const std::string value;
const TokenTypes tokenType;
};
class Lexer {
public:
Lexer(std::string program) {
tokenQueue = new std::deque<Token *>();
std::string str = "";
for (int i = 0; i < program.length(); i++) {
if ('0' <= program[i] && program[i] <= '9') {
while ('0' <= program[i] && program[i] <= '9') {
str += program[i++];
}
if (program[i] == '.') {
str += program[i];
i++;
while ('0' <= program[i] && program[i] <= '9') {
str += program[i++];
}
tokenQueue->push_back(new Token(str, TokenTypes::DOUBLE));
} else {
tokenQueue->push_back(new Token(str, TokenTypes::INTEGER));
}
str = "";
i--;
continue;
}
switch (program[i]) {
case '+':
tokenQueue->push_back(new Token("+", TokenTypes::OP2));
break;
case '-':
tokenQueue->push_back(new Token("-", TokenTypes::OP2));
break;
case '*':
tokenQueue->push_back(new Token("*", TokenTypes::OP1));
break;
case '/':
tokenQueue->push_back(new Token("/", TokenTypes::OP1));
break;
case '(':
tokenQueue->push_back(new Token("(", TokenTypes::LPAR));
break;
case ')':
tokenQueue->push_back(new Token(")", TokenTypes::RPAR));
break;
case ' ':
break;
default:
std::cerr << "Unexpected token: " << program[i] << std::endl;
break;
}
}
}
std::deque<Token *> *getQueue() {
return tokenQueue;
}
std::string toString() const {
std::string str = "";
for (Token *token : *tokenQueue) {
str += token->toString() + "\n";
}
return str;
}
private:
std::deque<Token *> *tokenQueue;
};