（Python学习6）Small Python

其实就是《Python源码剖析中的》

稍作改动与补充

#include <cstdio>
#include <cstring>
#include <map>
#include <string>
#include <iostream>


using namespace std;


#define PyObject_Head	\
	int ob_refcnt;	\
struct _typeobject * ob_type;


#define PyObject_Head_Init(typePtr)	\
	0, typePtr,


// ----基本对象---------------------------------------
typedef struct _object{
	PyObject_Head
}PyObject;


// ----类型对象---------------------------------------
typedef PyObject* (*FunAdd)(PyObject*, PyObject*);
typedef void (*FunPrint)(PyObject*);
typedef long (*FunHash)(PyObject*);


typedef struct _typeobject{
	PyObject_Head
	char * name;
	FunAdd pyAdd;
	FunPrint pyPrint;
	FunHash pyHash;
}PyTypeObject;


PyTypeObject PyType_Tpye =
{
	PyObject_Head_Init(&PyType_Tpye)
	"Type",
	0,
	0,
	0
};


// ----整数对象--------------------------------------
typedef struct _intobject{
	PyObject_Head
	int val;
}PyIntObject;


PyObject* int_add(PyObject* left, PyObject* right);
void int_print(PyObject * object);
long int_hash(PyObject * object);


PyTypeObject PyInt_Type =
{
	PyObject_Head_Init(&PyType_Tpye)
	"int",
	int_add,
	int_print,
	int_hash,
};


PyObject* PyInt_Create(int val){
	PyIntObject * int_object = new PyIntObject;
	int_object->ob_refcnt = 1;
	int_object->ob_type = &PyInt_Type;
	int_object->val = val;
	return (PyObject*)int_object;
}


PyObject* int_add(PyObject* left, PyObject* right){
	PyIntObject * int_result = (PyIntObject*)PyInt_Create(0);
	PyIntObject * int_left = (PyIntObject*)left;
	PyIntObject * int_right = (PyIntObject*)right;
	int_result->val = int_left->val + int_right->val;
	return (PyObject*)int_result;
}


void int_print(PyObject * object){
	PyIntObject * int_object = (PyIntObject*)object;
	printf("%d\n", int_object->val);
}


long int_hash(PyObject * object){
	PyIntObject * int_object = (PyIntObject*)object;
	long x = int_object->val;
	if (x == -1)
		x = -2;
	return x;
}




//----字符串对象-----------------------------------------------


typedef struct _strobject{
	PyObject_Head
	int length;
	long hash;
	char val[50];
}PyStrObject;


PyObject* str_add(PyObject* left, PyObject* right);
void str_print(PyObject * object);
long str_hash(PyObject * object);


PyTypeObject PyStr_Type =
{
	PyObject_Head_Init(&PyType_Tpye)
	"string",
	str_add,
	str_print,
	str_hash,
};


PyObject * PyStr_Create(const char * val){
	PyStrObject* str_object = new PyStrObject;
	str_object->ob_refcnt = 1;
	str_object->ob_type = &PyStr_Type;
	str_object->length = (val == NULL ? 0 : strlen(val));
	str_object->hash = -1;
	memset(str_object->val, 0, 50);
	if (val != NULL)
		strcpy(str_object->val, val);
	return (PyObject*)str_object;
}


PyObject * str_add(PyObject* left, PyObject* right){
	PyStrObject * str_result = (PyStrObject*)PyStr_Create(NULL);
	PyStrObject * str_left = (PyStrObject*)left;
	PyStrObject * str_right = (PyStrObject*)right;
	strcpy(str_result->val, str_left->val);
	strcat(str_result->val, str_right->val);
	return (PyObject*)str_result;
}


void str_print(PyObject* object){
	PyStrObject* str_object = (PyStrObject*)object;
	printf("%s\n", str_object->val);
}


long str_hash(PyObject * object){
	PyStrObject *str_object = (PyStrObject*)object;
	if (str_object->hash != -1)
	{
		return str_object->hash;
	}
	
	int len;
	unsigned char * p;
	long x;
	len = str_object->length;
	p = (unsigned char *)str_object->val;
	x = *p << 7;
	while (--len >= 0)
	{
		x = (1000003*x) ^ *p++;
	}
	x ^= str_object->length;
	if (x == -1)
		x = -2;
	str_object->hash = x;
	return x;
}


//----字典对象----------------------------------


typedef struct _dictobject 
{
	PyObject_Head
	map<long, PyObject*> dict;
}PyDictObject;


void dict_print(PyObject*);


PyTypeObject PyDict_Type = {
	PyObject_Head_Init(&PyType_Tpye)
	"dict",
	0,
	dict_print,
	0
};


PyObject * PyDict_Create(){
	PyDictObject * dict_object = new PyDictObject;
	dict_object->ob_refcnt = 1;
	dict_object->ob_type = &PyDict_Type;
	return (PyObject*)dict_object;
}


void PyDict_SetItem(PyObject* target, PyObject* key, PyObject* val){
	PyDictObject* dict_object = (PyDictObject*)target;
	long hash_key = key->ob_type->pyHash(key);
	dict_object->dict[hash_key] = val;
}


PyObject* PyDict_GetItem(PyObject* target, PyObject* key){
	long hash_key = key->ob_type->pyHash(key);
	map<long, PyObject*>& dict = ((PyDictObject*)target)->dict;
	map<long, PyObject*>::iterator it = dict.find(hash_key);
	map<long, PyObject*>::iterator end = dict.end();
	if (it == end)
		return NULL;
	else
		return it->second;
}


void dict_print(PyObject* object){
	PyDictObject * dict_object = (PyDictObject*)object;
	map<long, PyObject*>& dict = dict_object->dict;
	map<long, PyObject*>::iterator it = dict.begin();
	map<long, PyObject*>::iterator end = dict.end();
	printf("{\n");
	for ( ; it != end; ++it)
	{
		printf("\t%ld : ", it->first);
		it->second->ob_type->pyPrint(it->second);
	}
	printf("}\n");
}


//----解释过程----------------------------------------------------
PyObject* m_LocalEnv = PyDict_Create();


PyObject* GetObjectBySymbol(string& symbol);
void ExcutePrint(string& symbol);
void ExcuteAdd(string& target, string& source);
bool isSourceAllDigit(string& source);


void ExcuteCommand(string& command){
	string::size_type pos;
	if ((pos = command.find("print ")) != string::npos)
	{
		ExcutePrint(command.substr(6));
	}else if ((pos = command.find(" = ")) != string::npos)
	{
		string target = command.substr(0, pos);
		string source = command.substr(pos + 3);
		ExcuteAdd(target, source);
	}
}


PyObject* GetObjectBySymbol(string& symbol){
	PyObject* key = PyStr_Create(symbol.c_str());
	PyObject* val = PyDict_GetItem(m_LocalEnv, key);
	if (val == NULL)
	{
		printf("[Error]: \"%s\" is not defined !\n", symbol.c_str());
		return NULL;
	}
	return val;
}


void ExcutePrint(string& symbol){
	PyObject* object = GetObjectBySymbol(symbol);
	if (object != NULL)
		object->ob_type->pyPrint(object);
}


void ExcuteAdd(string& target, string& source){
	if (target == "" || source == "")
		return;


	string::size_type pos;
	if (isSourceAllDigit(source))
	{
		PyObject* key = PyStr_Create(target.c_str());
		PyObject* val = PyInt_Create(atoi(source.c_str()));
		PyDict_SetItem(m_LocalEnv, key, val);
	}else if ((pos = source.find("\"")) != string::npos)
	{
		PyObject* key = PyStr_Create(target.c_str());
		PyObject* val = PyStr_Create((source.substr(1, source.size()-2)).c_str());
		PyDict_SetItem(m_LocalEnv, key, val);
	}else if ((pos = source.find(" + ")) != string::npos)
	{
		PyObject* source_left = GetObjectBySymbol(source.substr(0, pos));
		PyObject* source_right = GetObjectBySymbol(source.substr(pos + 3));
		if (source_left != NULL && source_right != NULL && source_left->ob_type == source_right->ob_type)
		{
			PyObject* val = source_left->ob_type->pyAdd(source_left, source_right);
			PyObject* key = PyStr_Create(target.c_str());
			PyDict_SetItem(m_LocalEnv, key, val);
		}
	}


//	m_LocalEnv->ob_type->pyPrint(m_LocalEnv);
}


bool isSourceAllDigit(string& source){
	int len = source.size();
	for (int i=0; i<len; ++i)
		if (!isdigit(source[i]))
			return false;
	return true;
}


//----交互环境-----------------------------------------------


string info = "      ****** Small Python ***********";
string prompt = ">>> ";


int main(){
	string m_Command;
	cout << info << endl;
	cout << prompt;
	while (getline(cin, m_Command))
	{
		if (m_Command == "")
			;
		else if (m_Command == "exit")
			return 0;
		else
			ExcuteCommand(m_Command);
		cout << prompt;
	}
}