我作编译原理课程设计时写的一个图形化的小型开发环境

				// VM.H: Header file for VM.CPP
				#include "stack.h"    // Stack template class
				#include "mystring.h" // String class
				
				// The opcodes
				enum Opcode  {
				   OP_NOP,           // 空操作
				   OP_PUSH,          //  string [var]入栈 
				   OP_GETTOP,        // get string from top of stack (=assign) [var]
				   OP_DISCARD,       // 丢弃栈顶的值
				   OP_PRINT,         // 打印字符串 
				   OP_INPUT,         // 输入一个字符串 [var]
				   OP_JMP,           // 无条件转移[dest]
				   OP_JMPF,          // 为假则跳转 [dest]
				   OP_STR_EQUAL,     // 测试两个字符串是否相同
				   OP_BOOL_EQUAL,    // 测试两个不值是否相等 
				   OP_CONCAT,        // 连接两个字符串
				   OP_BOOL2STR,      // convert bool to string
				   JUMPTARGET        // not an opcode but a jump target;
				                     // the target field points to the jump instruction
				};
				
				// Instruction class
				class Instr {
				public:
				   Instr ()   {opcode = OP_NOP; operand = 0;}
				   Instr (Opcode _opcode)   {opcode = _opcode; operand = 0;}
				   Instr (Opcode _opcode, int _operand)  {opcode = _opcode; operand = _operand;}
				
				   Opcode    opcode;    // the opcode
				   int       operand;   // string number or target instruction
				};
				
				// Some defines and constants
				typedef Stack VM_Stack; // <  0 : boolean
				                             // >= 0 : index to string table
				const int ST_TRUE  = -1,  // stack codes for true/false
				          ST_FALSE = -2;
				
				const int MAX_STR = 100;  // 内存中最多能容纳的字符串数目(包括临时变量)
				
				// The virtual machine class
				class VMachine  {
				public:
				   VMachine ();
				   ~VMachine ();
				   void Read ();
				   void Execute ();
				   void Reset ();
				private:
				   // functions to make temp.copies of strings
				   int NewTempCopy ();
				   int NewTempCopy (int j);
				   int NewTempCopy (char *s);
				   void DelTempCopy (int i);
				
				   Instr   *instr;  // the instructions
				   int      ninstr; // 指令的编号 
				   String  *str[MAX_STR];  // the string table (NULL=entry not used)
				   VM_Stack stack;  // the stack
				};