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Burgaud

checking if Byref variable exists

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Burgaud
func sample (ByRef $x, $y, $z)
.
.
.
endfunc


local $a="text"
sample($a,1,2)

sample("",5,6)

Is it possible to pass a null into a function requiring it like above?

If so, how can a function determine if a parameter $x (ByRef) actually exists or was missed out?

 

 

 

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iamtheky

wouldnt it be easier to take the ByRef off, than attempt to ByRef a null.  I kind of want to know what the real world use case is for that tho.


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jchd

A ByRef variable always exists, else the function call is erroneous. Null is a value just like 5 or 6 or "text" or $a.

In the code below, _vardump is a function of mine (use search to find it) which ... dumps its argument.

Func sample(ByRef $x, $y, $z)
    ConsoleWrite(_vardump($x) & @LF)
EndFunc

Local $a="text"
sample($a, 1, 2)
sample("", 5, 6)
sample(Null, 5, 6)

It yields:

String       (4) 'text'
String       (0) ''
Keyword      Null

OTOH this doesn't work, irrespective of the second ByRef attribute:

Func sample(ByRef $x, $y, ByRef $z)
    ConsoleWrite(_vardump($x) & @LF)
EndFunc

Local $a="text"
sample($a, 1)

 


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