Brainfuckインタプリタ(ラムダ式+map使用版)

gistfile1.cpp

#include <iostream>
#include <map>
#include <functional>
#include <cstring>

using std::cout;
using std::cin;
using std::endl;

typedef std::pair<const char,std::function<void(void)>> Operator;
const int SourceLength=10000,MemorySize=30000;
char* Source;
unsigned char* Memory,* Ptr=0;
std::map<const char,std::function<void(void)>> Operators;
int Position;

int main(void)
{
    Source=new char[SourceLength];
    Memory=new unsigned char[MemorySize];
    Operators.insert(Operator('>',[&](void){Ptr++;}));
    Operators.insert(Operator('<',[&](void){Ptr--;}));
    Operators.insert(Operator('+',[&](void){(*Ptr)++;}));
    Operators.insert(Operator('-',[&](void){(*Ptr)--;}));
    Operators.insert(Operator('.',[&](void){cout<<*Ptr;}));
    Operators.insert(Operator(',',[&](void){*Ptr=cin.get();while(cin.get()!='\n');}));
    Operators.insert(Operator('[',[&](void){if(!*Ptr) for(int n=1;++Position<SourceLength&&n;) Source[Position]=='['?n++:Source[Position]==']'?n--:n;}));
    Operators.insert(Operator(']',[&](void){if(*Ptr) for(int n=1;--Position&&n;) Source[Position]=='['?n--:Source[Position]==']'?n++:n;}));
    while(1){
        for(int i=0;i<MemorySize;i++) Memory[i]=0;
        Ptr=Memory;
        Position=-1;
        cout<<"Please input program.(Max length is "<<SourceLength<<")"<<endl<<">";
        cin.getline(Source,SourceLength);
        if(!strcmp(Source,"x")) break;
        int Length=strlen(Source);
        while(++Position<Length){
            try{
                Operators.at(Source[Position])();
            }catch(...){
                cout<<"Oh... \""<<Source[Position]<<"\" is an illegal character.";
                break;
            }
        }
        cout<<endl;
    }
    delete[] Source;
    delete[] Memory;
    return 0;
}