houshou-launguage.cpp

#include <iostream>
#include <fstream>
#include <vector>
#include <iterator>
#include <algorithm>
#include <map>
#include <boost/function.hpp>
#include <boost/lambda/lambda.hpp>
#include <boost/lambda/if.hpp>
#include <boost/lambda/loops.hpp>
using namespace std;
using namespace boost;
using namespace boost::lambda;

int main(int, const char* argv[])
{
	typedef vector<unsigned char> Memory;
	typedef Memory::iterator      Pointer;
	cin.unsetf(ios_base::skipws);

	// メモリ
	Memory imem, dmem(65536);

	// プログラム読み込み
	ifstream fin(argv[1]);
	if( fin )
	  copy( istream_iterator<char>(fin),
	        istream_iterator<char>(), back_inserter(imem) );

	// ポインタ初期化
	Pointer iptr_s=imem.begin(), dptr_s=dmem.begin();
	int t_s;

	// Bfの各命令に対応する関数の定義
	map< char, std::function<void()> > action_for;
	{
		var_type<Pointer>::type iptr(var(iptr_s));
		var_type<Pointer>::type dptr(var(dptr_s));
		var_type<int>::type        t(var(t_s));

		action_for['h']=  ++ dptr;
		action_for['o']=  -- dptr;
		action_for['u']=  ++*dptr;
		action_for['s']=  --*dptr;
		action_for['y']=  cout << *dptr;
		action_for['k']=  cin >> *dptr;
		action_for['a']=  if_( !*dptr )[
		                    for_(t=1, t, ++iptr)[
		                      if_( *iptr == 'a' )[ ++t ],
		                      if_( *iptr == 'n' )[ --t ]
		                    ]];
		action_for['n']=  (iptr-=2, for_(t=-1, t, --iptr)[
		                    if_( *iptr == 'a' )[ ++t ],
		                    if_( *iptr == 'n' )[ --t ]
		                  ], ++iptr);
	}

	// 実行。無関係な文字はスキップする
	while( iptr_s != imem.end() )
		if( std::function<void()> f = action_for[ *iptr_s++ ] )
			f();
}