myscript/tokenizer.cpp at main · yota22721/myscript · GitHub

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#include <iostream>
#include <cstdlib>
#include <cctype>
#include<cstring>
#include<vector>
#include "tokenizer.hpp"


using namespace std;


static const char* keywords[] ={"if","else","for","while","return"}; //basic operator's list

//If the token is equal to number,alphabet(small or capital letter) and '_', return true.
bool Tokenizer::isAlnum(char c)
{
    if(isalnum(c) || c == '_'){
        return true;
    }else{
        return false;
    }

}

//if the cursor matches a symbol, return true.
bool Tokenizer::isSymbol(void)
{
    char* p = cursor;

    for(const char* symbol:symbols){
        int len =strlen(symbol);

        if(memcmp(cursor,symbol,len) == 0){
            Token Token(T_RESERVED,p,len);
            tokens.push_back(Token);

            cursor +=len;
            return true;
        }
    }
    return false;


}

//If the cursor is keyword, return true.
bool Tokenizer::isKeyword(void)
{
    char* p =cursor;

    for(const char* keyword: keywords){
        int len = strlen(keyword);

        if(memcmp(cursor,keyword,len) == 0 && isAlnum(*(cursor+len))){

            Token Token(T_IDENT,p,len);
            tokens.push_back(Token);
            cursor +=len;
            return true;
        }
    }
    return false;
}

//If the cursor is identifer, return true.
bool Tokenizer::isIdentifier(void)
{
    char* p = cursor;
    int len = 0;

    for(;isAlnum(*cursor);cursor++) len++;

    if(len > 0){
        Token Token(T_IDENT,p,len);
        tokens.push_back(Token);
        return true;
    }
    return false;
}

//If the cursor is equal to figure, return true.
bool Tokenizer::isNumber(void)
{
    char* p =cursor;
    int len =0;


    for(;isdigit(*cursor);cursor++) len++;


    if(len>0){
        Token Token(T_NUM,p,len);
        tokens.push_back(Token);


        return true;
    }
    return false;
}

//if the cursor is equal to \n, return ture.
bool Tokenizer::isNewLine(void)
{
    char* p =cursor;

    if (*cursor == '\n'){
        if(tokens.size() != 0 && tokens.back().str != "\n"){
            Token Token(T_RESERVED,cursor,1);
            tokens.push_back(Token);
        }
        cursor++;
        return true;
    }else{
        return false;
    }


}
//If the cursor is whitespace, skip to next character.
void Tokenizer::skip(void)
{
    while(*cursor != '\n' && isspace(*cursor )){
        cursor++;
    }
}

//Tokenize the character
vector<Token> Tokenizer::tokenize(const char* input)
{
    cursor = (char*)input;
    tokens.clear();


    while(*cursor){
            skip();

            if(isSymbol()){

            }else if(isKeyword()){

            }else if(isNumber()){

            }else if(isIdentifier()){

            }else if(isNewLine()){

            }else{
                cerr << "Error : invalid character "<< *cursor<<endl;
                exit(1);
            }

    }
    if(tokens.back().str == "\n"){
        tokens.pop_back();
    }
    tokens.push_back(Token(T_EOF,cursor,0));
    /*
    cout << string(30,'-')<<endl;
    for(Token token:tokens) token.print();
    cout << string(30,'-')<<endl;
    */


    return tokens;
}