fpExpressionParser

[wp]

Two questions regarding fpExpressionParser:

• Following the examples with the built-in functions I added a user-defined function "power" to the parser by calling "Identifiers.AddFunction('power', 'F', 'FF', @ExprPower)". The functions works fine as long as I use a floating point number for the exponent, i.e. "power(x, 2.0)" is ok, but with integer exponents (i.e. "power(x, 2)") I get the error that a float is expected. Is there a way to automatically convert integers to floats?
  
• I'd like to add a new symbol "^" as a short-cut to the power function. Is this possible?
  

[Leonor]

Hello wp, I don't know if there is a way to convert automatically  integers to floats, but I do this way:

procedure integersToFloat(iValue: integer; var DblResult: Double);
     var
        VrnValue: Variant;
begin
     VrnValue := iValue;
     DblResult :=  VrnValue;
end;

[Leledumbo]

I'd like to add a new symbol "^" as a short-cut to the power function. Is this possible?

Looking at the source code, it seems impossible. The operators are hardcoded and no user defined operator handling provided.

[wp]

@Leonor: This is a stand-alone procedure (BTW: wouldn't a simple assignment "floatVariable := integerVariable" have the same effect?). I am seeking a way how to tell fpExpressionParser to do such a conversion internally.

It looks as if fpExpressionParser is not prepared for this feature. So it seems that I'll have to patch the sources.

[marcov]

Or use the "symbolic" expression parser.