public static Expression ToCallExpression(ParameterExpression Pr, FExpr fx, object paramsObject)
{
if (fx.Name == nameof(BuilinFuncsMap.Left))
{
if (fx.Args.Count < 2)
{
throw new ArgumentException($"'{nameof(BuilinFuncs.Left)} require 2 params'");
}
var mc = BuilinFuncsMap.Left;
var mx = ToExpression(Pr, fx.Args[0], paramsObject);
var len = ToExpression(Pr, fx.Args[1], paramsObject);
if (len is UnaryExpression)
{
if (((UnaryExpression)len).Operand is ConstantExpression)
{
var val = ((ConstantExpression)(((UnaryExpression)len).Operand)).Value;
val = Convert.ChangeType(val, typeof(int));
len = Expression.Constant(val);
}
}
return(Expression.Call(mc, mx, len));
}
if (fx.Name == nameof(BuilinFuncsMap.Concat))
{
var args = new List <Expression>();
foreach (var x in fx.Args)
{
var FX = ToExpression(Pr, x, paramsObject);
if (FX is UnaryExpression && ((UnaryExpression)FX).Operand is ConstantExpression)
{
args.Add(((UnaryExpression)FX).Operand);
}
else
{
args.Add(FX);
}
}
var axs = Expression.NewArrayInit(typeof(string), args);
var mc = BuilinFuncsMap.Concat;
return(Expression.Call(mc, axs));
}
throw new NotImplementedException();
}
public FXExpr Eval(string expression)
{
List <string> tokens = TokenParsers.GetTokens(expression);
Stack <FXExpr> operandStack = new Stack <FXExpr>();
Stack <string> operatorStack = new Stack <string>();
int tokenIndex = 0;
while (tokenIndex < tokens.Count)
{
string token = tokens[tokenIndex];
FXExpr preOperand = null;
if (token[0] == '{' && token[token.Length - 1] == '}')
{
operandStack.Push(new PExpr(token));
tokenIndex += 1;
continue;
}
if (token == "(")
{
if (operandStack.Count > 0)
{
preOperand = operandStack.Pop();
}
if (preOperand is NExpr)
{
string subExpr = getSubExpression(tokens, ref tokenIndex);
var fx = new StrParser();
var indexOfCom = -1;
List <FXExpr> _args = null;
if ((indexOfCom = subExpr.IndexOf(",")) > -1)
{
var left = (new StrParser()).Eval(subExpr.Split(',')[0]);
var rStr = subExpr.Substring(indexOfCom + 1, subExpr.Length - indexOfCom - 1);
var right = (new StrParser()).Eval(subExpr.Substring(indexOfCom + 1, subExpr.Length - indexOfCom - 1));
_args = ParseArgs(right);
_args.Insert(0, left);
}
var args = fx.Eval(subExpr);
var ret = new FExpr()
{
Name = (preOperand as NExpr).Value,
Args = _args ?? (new FXExpr[] { args }).ToList()
};
//var args = Eval(subExpr);
operandStack.Push(ret);
}
else
{
string subExpr = getSubExpression(tokens, ref tokenIndex);
if (preOperand != null)
{
operandStack.Push(preOperand);
}
operandStack.Push(Eval(subExpr));
}
continue;
}
if (token == ")")
{
throw new ArgumentException("Mis-matched parentheses in expression");
}
//If this is an operator
if (Array.IndexOf(TokenParsers._operators, token) >= 0)
{
while (operatorStack.Count > 0 && Array.IndexOf(TokenParsers._operators, token) < Array.IndexOf(TokenParsers._operators, operatorStack.Peek()))
{
string op = operatorStack.Pop();
var arg2 = operandStack.Pop();
var arg1 = operandStack.Pop();
var BExpr = new BExpr
{
Operator = TokenParsers._operators[Array.IndexOf(TokenParsers._operators, op)],
Left = arg1,
Right = arg2
};
operandStack.Push(BExpr);
}
operatorStack.Push(token);
}
else
{
operandStack.Push(new NExpr(token));
}
tokenIndex += 1;
}
while (operatorStack.Count > 0)
{
string op = operatorStack.Pop();
var arg2 = operandStack.Pop();
var arg1 = operandStack.Pop();
var ret = new BExpr
{
Left = arg1,
Right = arg2,
Operator = TokenParsers._operators[Array.IndexOf(TokenParsers._operators, op)]
};
operandStack.Push(ret);
}
return(operandStack.Pop());
}
