internal static Expression ToExpression(ParameterExpression Pr, FXExpr Expr, object paramsObject)
{
if (Expr is NExpr)
{
var nExpr = Expr as NExpr;
if (nExpr.ValueType != ConstTypeEnum.None)
{
var Cx = Expression.Constant(nExpr.GetValue());
return(Expression.Convert(Cx, typeof(object)));
}
else
{
var mb = Pr.Type.GetProperties().FirstOrDefault(p => p.Name.ToLower() == nExpr.Value.ToLower());
if (mb == null)
{
throw new Exception($"'{nExpr.Value}' was not found in ${Pr.Type.FullName}");
}
var ret = Expression.MakeMemberAccess(Pr, mb);
return(ret);
}
}
if (Expr is BExpr)
{
return(ToOperandExpression(Pr, Expr as BExpr, paramsObject));
}
if (Expr is PExpr)
{
return(ToConstExpression(Expr as PExpr, paramsObject));
}
if (Expr is FExpr)
{
return(ToCallExpression(Pr, Expr as FExpr, paramsObject));
}
throw new NotImplementedException();
}
private List <FXExpr> ParseArgs(FXExpr Expr)
{
if (Expr is NExpr)
{
var vExpr = Expr as NExpr;
return
(vExpr.Value.Split(',')
.Select(p => (new StrParser()).Eval(p))
.ToList());
}
if (Expr is BExpr)
{
var bExpr = Expr as BExpr;
var lItems = ParseArgs(bExpr.Left);
var lX = lItems[lItems.Count - 1];
var rItems = ParseArgs(bExpr.Right);
var rX = rItems[0];
var ret = new List <FXExpr>();
ret.AddRange(lItems.Where(p => p != lX));
ret.Add(new BExpr {
Left = lX,
Right = rX,
Operator = bExpr.Operator
});
ret.AddRange(rItems.Where(p => p != rX));
return(ret);
}
if (Expr is FExpr)
{
return((new FXExpr[] { Expr }).ToList());
}
if (Expr is PExpr)
{
return((new FXExpr[] { Expr }).ToList());
}
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());
}
