Using a function call in an array assignment causes 2 function calls

[jguinch]

With this code :

Local $aArray[1]

$aArray[ _myFunction() ] = "myString"

Func _myFunction()
	ConsoleWrite("_myFunction" & @CRLF)
	Return 0
EndFunc

"myFunction" appears two times in the output console, but it should once.

[jguinch]

Also, this code is a good example of what happends :

Local $aArray[1]
$aArray[  0 * MsgBox(0, "", "Appears twice")  ] = MsgBox(0, "", "Appears once")

[Melba23]

Interesting that it does not do the same when you set the function to a variable:

Local $aArray[1]

$aArray[ _Function() ] = "myString"

ConsoleWrite(@CRLF)

$hFunction = _Function()
$aArray[ $hFunction ] = "myString"

Func _Function()
	ConsoleWrite("_Function @ " & @MSEC & @CRLF)
	Sleep(100)
	Return 0
EndFunc

M23

[anonymous]

Replying to Melba23:

Interesting that it does not do the same when you set the function to a variable

Not very interesting. You assign the return value of the function to a variable and then evaluate that variable expression (twice).

[jguinch]

I don't really understand what you mean in comment3...

[BrewManNH]

You're calling the function to get the returned value for the array assignment, then you're calling it again when you actually set the value to the array. Run this modification to your code to see what's happening.

#include <Array.au3>
Local $aArray[2]

$aArray[ _myFunction() ] = "myString"
_ArrayDisplay($aArray)
Func _myFunction()
    Local Static $Return = -1
	ConsoleWrite("_myFunction = " & $Return & @CRLF)
    $Return += 1
	Return $Return
EndFunc

It calls the function the first time to see what element of the array to set it to, then when AutoIt does the actual declaration for the element it calls it again to see where it's going. You'll notice that the only element with anything in it is $aArray[1] because that's what the return value is when you set the string to the array.

So, I don't know if this is a bug, but it looks like a bad idea to use a function call to determine where in an array to put something, at least don't do it in the actual declaration statement, because you won't be able to be 100% sure it's going where you think it's going.

[anonymous]

@BrewManNH : you pointed exatly what I was trying to do to assist a forum user in this thread : ​http://www.autoitscript.com/forum/topic/169135-flexibility-with-declaring-an-array/

I wanted to post this kind of code :

#Include <Array.au3>

Local $a[10]

$a[ _i() ] =  "First row"
$a[ _i() ] =  "Second row"
$a[ _i() ] =  "Third row"

_ArrayDisplay($a)


Func _i() 
	Local Static $iIndex = -1
	$iIndex += 1
	Return $iIndex
EndFunc

But when I saw the result, I decided to write a ticket here.
For me, it is a bug, but you decid :-)
If not, maybe something about this "bad" uasge should appear in the help file

[Jpm]

Hi,
I sent a fix to Jon

[Jpm]

Hi,
I look again to what I try to do,
My fix is not working
So perhaps Jon will have a solution

[Jpm]

Hi, I think I found a working solution
It was hard speially when both sie refer to subcript defined by array elements
Sent Fix to Jon