Procedure default argument bypass?

[charvista]

Not sure it can in any way, but I was wondering if we can jump an argument value to keep the "default" value?

Code: Select all

Procedure Ax(S.i,D.i=5,E.i=6)
    Debug S
    Debug D
    Debug E
EndProcedure

Ax(100)
Ax(100,#PB_Default,4)

#PB_Default is NOT the correct solution, but that way you can understand my idea. I would like to keep the default for D.i=5 while changing the argument E.i to 4.
Is there a legal way?
Thanks

[Shield]

You have to create another procedure without the parameter D and then call the existing one with the correct value
since PB doesn't support function overloading or named parameters.

[Danilo]

Code: Select all

Procedure Ax(S.i,D.i=5,E.i=6)
    Debug S
    Debug D
    Debug E
EndProcedure

Ax(100)
Ax(100,#PB_Default,4)

#PB_Default is NOT the correct solution, but that way you can understand my idea.

If you don't need -1 (#PB_Default), you can use it like your example.

Code: Select all

Procedure Ax(S.i,D.i=5,E.i=6)
    If D = #PB_Default : D = 5 : EndIf
    Debug S
    Debug D
    Debug E
EndProcedure

Ax(100)
Ax(100,#PB_Default,4)

I've seen a BASIC language that does allow empty expressions for procedure args, so the default is taken.
Like "Ax(100,,4)" - maybe a feature request?

[charvista]

Nice idea as workaround Danilo, thank you! So far the best one, but not very practical, as -1 (#PB_Default) is not an universal way to tell the called procedure that I want to keep the default value, because -1 can be a value, too.

Ax(100,,4)

Yes, this is exactly what I had in thoughts.
Feature request +1
If PureBasic need to "invent" something else to avoid copying existing syntaxes, then

Ax(100,*,4)

is very nice too.

[charvista]

@Shield
Do you mean like this:

Code: Select all

Procedure Ax(S.i,D.i=5,E.i=6)
    Debug S
    Debug D
    Debug E
EndProcedure

Procedure Ax2(S.i,E.i=6)
    Ax(S,5,E)
EndProcedure

Ax2(100)
Ax2(100,4)

Not a bad idea either...

[Shield]

Yes, exactly.

But it would be way cooler if you could create procedures with the same name and with the compiler
deciding what function to call based on the number (and type) of the parameters.

[STARGÅTE]

But in PB you can't change the type of a variable, so you know the type of your variables, so you know which procedure you must call.

[Tenaja]

This is a super simple solution.

Code: Select all

#Ax_p1_default = 5
Procedure Ax(S.i,D.i=#Ax_p1_default,E.i=6)
    Debug S
    Debug D
    Debug E
EndProcedure

Ax(100,#Ax_p1_default, 4)

If you can't bother typing in whatever name you give #Ax_p1_default, then make a macro.

Code: Select all

Macro Ax2(p0, p2)
    Ax(p0,#Ax_p1_default, p2)
endmacro