Brainfuckインタプリタ(std::map+ラムダ式使用)改良版

gistfile1.cpp

#include <iostream>
#include <map>
#include <functional>
#include <string>
#include <memory>

int main(void)
{
    typedef std::pair<const char,std::function<void(void)>> Op;
    std::map<const char,std::function<void(void)>> Ops;
    const int SourceLength=10000,MemorySize=30000;
    std::unique_ptr<unsigned char> Memory(new unsigned char[MemorySize]);
    std::string Source(SourceLength,0);
    int Position;
    unsigned char* Ptr;
    Ops.insert(Op('>',[&](void){Ptr++;}));
    Ops.insert(Op('<',[&](void){Ptr--;}));
    Ops.insert(Op('+',[&](void){(*Ptr)++;}));
    Ops.insert(Op('-',[&](void){(*Ptr)--;}));
    Ops.insert(Op('.',[&](void){std::cout<<*Ptr;}));
    Ops.insert(Op(',',[&](void){*Ptr=std::cin.get();while(std::cin.get()!='\n');}));
    Ops.insert(Op('[',[&](void){if(!*Ptr) for(int n=1;++Position<SourceLength&&n;) Source[Position]=='['?n++:Source[Position]==']'?n--:n;}));
    Ops.insert(Op(']',[&](void){if(*Ptr) for(int n=1;--Position&&n;) Source[Position]=='['?n--:Source[Position]==']'?n++:n;}));
    while(true){
        for(int i=0;i<MemorySize;i++) Memory.get()[i]=0;
        Ptr=Memory.get();
        Position=-1;
        std::cout<<"Please input program.(Max length is "<<SourceLength<<")"<<std::endl<<">";
        std::cin>>Source;
        if(Source=="x") break;
        int Length=Source.length();
        while(++Position<Length){
            try{
                Ops.at(Source[Position])();
            }catch(...){
                std::cout<<"Oh... \""<<Source[Position]<<"\" is an illegal character.";
                break;
            }
        }
        std::cout<<std::endl;
    }
    return 0;
}