NJUPT-Compile/1/Parser.cpp

//
// Created by kagura on 4/24/24.
//

#include "Parser.h"

Parser::Parser(const char *filename) {
    file.open(filename,ios::in);
    if (!file.is_open()){
        printf("文件打开失败\n");
        exit(1);
    }
}

void Parser::parse() {
    char curr;
    string name; // 当前获取到的名称
    while (file.get(curr)){
        switch (state) {
            case VOID:
                if (curr >='0' && curr <='9'){ // 整数
                    state = INTEGER;
                    name += curr;
                } else if (curr == ' ' || curr == '\n' || curr == '\t') { // 空格.去掉
                    continue;
                } else if ((curr >='a' && curr <='z') || (curr >='A' && curr <='Z') || curr == '_'){ // 名称
                    state = NAME;
                    name += curr;
                } else if (curr == '/'){
                    file.get(curr);
                    if (curr == '/'){
                        state = COMMENT_LINE;
                    } else if (curr == '*'){
                        state = COMMENT_BLOCK;
                    } else{
                        state = VOID;
                    }
                } else if (classifier.isIsolator(curr)){
                    printf("(5,\"%c\")\n",curr);
                    append_result(format("{}",curr));
                    state = VOID;
                } else if (classifier.isOperator(curr)){
                    // 多读下一个字符
                    char c = file.peek();
                    if (c=='='){
                        printf("(4,\"%c%c\")\n",curr,c);
                        append_result(format("{}{}",curr,c));
                        file.get(curr);
                    } else if (curr == '>'||curr == '<'||curr == '+'||curr == '-'||curr == '&'||curr == '|'){
                        // 可能是++ -- << >> && || << >>
                        if (c == curr){
                            printf("(4,\"%c%c\")\n",curr,c);
                            append_result(format("{}{}",curr,c));
                            file.get(curr);
                        } else{
                            printf("(4,\"%c\")\n",curr);
                            append_result(format("{}",curr));
                        }
                    } else{
                        printf("(4,\"%c\")\n",curr);
                        append_result(format("{}",curr));
                    }
                }

                else{
                    state = VOID;
                }
                break;
            case INTEGER:
                if (curr >='0' && curr <='9'){ // 整数
                    name += curr;
                } else if (curr == ';') {
                    printf("(3,\"%s\")\n",name.c_str());
                    append_result(name);
                    file.unget();
                    name.clear();
                    state = VOID;
                } else if (curr == ' ' || curr == '\n' || curr == '\t') { // 空格
                    printf("(3,\"%s\")\n",name.c_str());
                    result += name; // 去掉空格
                    name.clear();
                    state = VOID;
                } else{
                    state = VOID;
                }
                break;
            case NAME:
                if ((curr >='a' && curr <='z') || (curr >='A' && curr <='Z') || (curr >='0' && curr <='9')){
                    name += curr;
                } else {
                    if (classifier.isreserveNames(name)){
                        printf("(1,\"%s\")\n",name.c_str());
                    }else{
                        printf("(2,\"%s\")\n",name.c_str());
                    }
                    append_result(name);
                    name.clear();
                    file.unget(); // 回退一个字符
                    state = VOID;
                }
                break;
            case COMMENT_LINE:
                if (curr == '\n'){
                    state = VOID;
                }
                break;
            case COMMENT_BLOCK:
                if (curr == '*'){
                    file.get(curr);
                    if (curr == '/'){
                        state = VOID;
                    }
                }
                break;
            }
    }
}

void Parser::print_result() {
    cout<<result<<endl;
}

void Parser::append_result(const string &name) {
    if (state==NAME){
        if (classifier.isIsolator(name[0])||classifier.isOperator(name[0])){ // 不用加空格
            result += name;
        }else {
            if (classifier.isreserveNames(name)){
                result += name + " ";
            }else{
                result += name;
            }
        }
    }else if (last_state==SEMICOLON){
        if (name != ";"){
            result += name;
            last_state = VOID;
        }
    }else{
        result += name;
    }

    if (name == ";"){
        last_state = SEMICOLON;
    }
}