private static EvalValue CalcWhile(IEnvironment env, AstWhile ast)
{
// 返回值为最后一条语句或表达式的值
var ret = new EvalValue();
while (true)
{
var cond = ast.condition.Eval(env);
if (cond.type == EvalValueType.INT && cond.intVal > 0)
{
// 当条件满足时执行代码块中的每一条子语句
foreach (var item in ast)
{
ret = item.Eval(env);
}
}
else if (cond.type == EvalValueType.STRING)
{
throw new RunTimeException("条件表达式不能为字符串", ast.condition);
}
else
{
break;
}
}
return(ret);
}
private static EvalValue CalcIf(IEnvironment env, AstIf ast)
{
// 返回值为执行的最后一条语句或表达式的值
var ret = new EvalValue();
var cond = ast.condition.Eval(env);
if (cond.type == EvalValueType.STRING)
{
throw new RunTimeException("条件表达式不能为字符串", ast.condition);
}
else if (cond.type == EvalValueType.INT && cond.intVal > 0)
{
foreach (var item in ast)
{
ret = item.Eval(env);
}
}
else if (ast.elseBlock != null)
{
// 有else块
foreach (var item in ast.elseBlock)
{
ret = item.Eval(env);
}
}
return(ret);
}
private static EvalValue CalcFunction(FuncEnvironment env, AstFunction ast)
{
// 初始化实参
var callee = env.GetMainEnv().GetFuncDef(ast.token.GetText());
if (callee != null)
{
// 脚本方法
var paramList = callee.paramList;
for (var i = 0; i < paramList.length; ++i)
{
var item = paramList.GetName(i);
if (ast.args.ChildrenCount() <= i)
{
throw new RunTimeException("实参不足", ast);
}
var argItem = ast.args.ChildAt(i) as AstExpression;
env.AddArg(item, argItem.Eval(env.parent));
}
// 执行函数体
var funcBody = callee.block;
var ret = new EvalValue();
foreach (var item in funcBody)
{
try
{
ret = item.Eval(env);
}
catch (ReturnException)
{
break;
}
}
if (env.Get("return@" + env.GetScopeName()) != null)
{
return(env.Get("return@" + env.GetScopeName()));
}
return(ret);
}
else
{
var csm = env.GetMainEnv().GetCsFuncDef(ast.token.GetText());
if (csm != null)
{
// CS方法
var csRet = csm(ast.args.ToArgArray(env));
var ret = new EvalValue(csRet);
return(ret);
}
}
throw new RunTimeException("函数未定义:" + ast.token.GetText() + "()", ast);
}
/// <summary>
/// 对节点进行求值
/// </summary>
/// <param name="ast"></param>
/// <returns></returns>
public static EvalValue Eval(IEnvironment env, AstNode ast)
{
var result = new EvalValue();
if (ast is AstProg)
{
result = CalcProg(env, ast as AstProg);
}
else if (ast is AstExpression)
{
result = CalcExpression(env, ast as AstExpression);
}
else if (ast is AstIf)
{
result = CalcIf(env, ast as AstIf);
}
else if (ast is AstWhile)
{
result = CalcWhile(env, ast as AstWhile);
}
else if (ast is AstReturn)
{
result = CalcReturn(env, ast as AstReturn);
}
else if (ast is AstStringLiteral)
{
result = CalcString(env, ast as AstStringLiteral);
}
else if (ast is AstNumberLiteral)
{
result = CalcNumber(env, ast as AstNumberLiteral);
}
else if (ast is AstIdentifier)
{
result = CalcIdentifier(env, ast as AstIdentifier);
}
else if (ast is AstFuncDef)
{
env.GetMainEnv().SetFuncDef(ast as AstFuncDef);
result = EvalValue.ZERO; // 函数定义，不返回任何有意义的值
}
else if (ast is AstFunction)
{
result = CalcFunction(new FuncEnvironment(env, Utils.GetScopeString()), ast as AstFunction); // 函数调用
}
else
{
throw new RunTimeException("非法节点类型: " + ast.GetType().ToString(), ast);
}
Utils.LogDebug("[R] 正在计算[{0}]{1}的值，结果为：{2}", ast.GetType(), ast, result);
return(result);
}
public static EvalValue CallFunc(FuncEnvironment env, AstFuncDef callee, params object[] args)
{
var paramList = callee.paramList;
if (args.Length < paramList.length)
{
throw new RunTimeException(string.Format("实参不足: 需要{0}个，提供了{0}个", paramList.length, args.Length));
}
for (var i = 0; i < paramList.length; ++i)
{
var item = paramList.GetName(i);
var argItem = args[i];
if (argItem is System.Int32)
{
env.AddArg(item, new EvalValue((int)argItem));
}
else if (argItem is System.String)
{
env.AddArg(item, new EvalValue(argItem as System.String));
}
else
{
throw new RunTimeException("参数类型不正确:" + argItem.GetType().ToString());
}
}
// 执行函数体
var funcBody = callee.block;
var ret = new EvalValue();
foreach (var item in funcBody)
{
try
{
ret = item.Eval(env);
}
catch (ReturnException)
{
break;
}
}
if (env.Get("return@" + env.GetScopeName()) != null)
{
return(env.Get("return@" + env.GetScopeName()));
}
return(ret);
}
private static EvalValue CalcProg(IEnvironment env, AstProg ast)
{
var ret = new EvalValue();
foreach (var item in ast)
{
try
{
ret = item.Eval(env);
}
catch (ReturnException)
{
break;
}
}
if (env.Get("return@Main") != null)
{
return(env.Get("return@Main"));
}
return(ret);
}
/// <summary>
/// 设置变量的值
/// </summary>
/// <param name="name"></param>
/// <param name="content"></param>
public void Set(string name, EvalValue content)
{
m_hashMap[name] = content;
}
private static EvalValue CalcExpression(IEnvironment env, AstExpression ast)
{
// 先计算右值
var right = new EvalValue();
// 可能的运算符 == <= >= && || + - * / < > %
// && ||
// >= <= == > <
// + -
// * / %
try
{
Stack <AstPun> ops = new Stack <AstPun>();
Queue <AstNode> output = new Queue <AstNode>();
// 转为后缀表达式
foreach (var item in ast)
{
if (item is AstFactor || item is AstExpression)
{
output.Enqueue(item);
}
else if (item is AstPun)
{
while (ops.Count > 0 && ops.Peek() >= (item as AstPun))
{
output.Enqueue(ops.Pop());
}
ops.Push(item as AstPun);
}
else
{
throw new RunTimeException("非法表达式项", item);
}
}
while (ops.Count > 0)
{
output.Enqueue(ops.Pop());
}
// 后缀表达式求值
Stack <EvalValue> result = new Stack <EvalValue>();
while (output.Count > 0)
{
var item = output.Dequeue();
if (item is AstFactor || item is AstExpression)
{
result.Push(item.Eval(env));
}
else if (item is AstPun)
{
var val2 = result.Pop();
var val1 = result.Pop();
EvalValue res;
string op = (item as AstPun).token.ToString();
if (op == "+")
{
res = val1 + val2;
}
else if (op == "-")
{
res = val1 - val2;
}
else if (op == "*")
{
res = val1 * val2;
}
else if (op == "/")
{
res = val1 / val2;
}
else if (op == "%")
{
res = val1 % val2;
}
else if (op == "<")
{
res = val1 < val2;
}
else if (op == ">")
{
res = val1 > val2;
}
else if (op == "==")
{
res =
(val1.type == EvalValueType.INT && val2.type == EvalValueType.INT &&
val1.intVal == val2.intVal) ||
(val1.type == EvalValueType.STRING && val2.type == EvalValueType.STRING &&
val1.strVal == val2.strVal) ?
EvalValue.TRUE : EvalValue.FALSE;
}
else if (op == "<=")
{
res = val1 <= val2;
}
else if (op == ">=")
{
res = val1 >= val2;
}
else if (op == "&&")
{
res = (val1 > EvalValue.ZERO).intVal > 0 && (val2 > EvalValue.ZERO).intVal > 0 ?
EvalValue.TRUE : EvalValue.FALSE;
}
else if (op == "||")
{
res = (val1 > EvalValue.ZERO).intVal > 0 || (val2 > EvalValue.ZERO).intVal > 0
? EvalValue.TRUE : EvalValue.FALSE;
}
else
{
throw new RunTimeException("非法运算符" + op);
}
result.Push(res);
}
else
{
throw new RunTimeException("非法表达式项", item);
}
}
if (result.Count != 1)
{
throw new RunTimeException("表达式结果不正确");
}
right = result.Pop();
}
catch (Exception e)
{
throw new RunTimeException("计算表达式的值时出错:" + e.Message, ast);
}
if (ast.isAssignExpression)
{
// 赋值语句
env.Set(ast.leftFactor, right);
}
return(right);
}
