PureBasic Forums - English

See Subject.

I don't get it? Macros are definitions... what you're asking is like asking
for DimIf... care to explain what I'm obviously misunderstanding?

Ever played with the fasm macros? They seem more powerful then asm
itself!

I like this.

I thought you meant something else when first I saw your post (if macro defined ..)

So .. the compiler actually builds two (or more) sets of code and tests to see which to use at runtime? Nifty. It would makes some things Macro-able that currently are not. As per your example.l

maybe you can just do it this way. or using CompilerIf statement.

I think he means at compile time. If the third argument is not supplied, use one definition, else use the other.

That would be smarter.


Edit:

El_Choni wrote:I think he means at compile time.

Exact! Otherwise I could just write a more elegant Procedure.

Dare2 wrote:That would be smarter.


Edit:

Code: Select all

MacroIf c = #PB_Undefined

FloHimself wrote:

Code: Select all

Macro MidU(a, b, c=-1) 
  MacroIf c = -1 
    Mid(a, b, Len(a) - b + 1) 
  MacroElse 
    Mid(a, b, c) 
  EndMacroIf 
EndMacro

String.s = "Hallo du da" 

Debug MidU(String, 4, 3) 
Debug MidU(String, 4)

Ever played with the fasm macros? They seem more powerful then asm
itself!

In Deinem Beispiel würde das ja funktionieren, und der Compiler müsste nur einen der beiden Aufrufe in den Code einsetzen. Wenn nun aber der dritte Parameter eine Variable ist, dann müsste der Compiler im Code eine If/Else-Abfrage einsetzen ... und in diesem Fall würde folgendes ausreichen:

[edit]OK (have to translate it):
In your example this would work and the compiler would replace the code by one of the MID-calls. But if the macro is "called" with a variable (and not with a constant, than the compiler has to insert an if-else ... and for this the following macro would be ok too:
[/edit] Tja, Deine Variante wäre einfach etwas mehr optimiert!

[edit]Translation:
Yes, your version would result in more optimized code!

cu, helpy

helpy wrote:But if the macro is "called" with a variable (and not with a constant, than the compiler has to insert an if-else ... and for this the following macro would be ok too:

Nope. If the macro is called with only 2 parameters the macro should
evaluate to : If you call it with 3 parameters, whether with a constant or variable, it
should evaluate to: There is no need to have a If-Else.

@FloHimself

You are right!

I was thinking the wrong way ... "what if the third parameter is a variable, which would be -1" ... wrong question! because the third parameter must not have the value -1 in any case.

cu, helpy

So is this how we would handle native function overloading?

@FloHimself : +1