From: "Eric Lippert (Microsoft Scripting Dev)" <EricLi@Microsoft.com>
Subject: Re: ByRef not working in WSH/VBS
Date: 1999/01/29
Message-ID: <ugBDfw9S#GA.230@uppssnewspub04.moswest.msn.net>#1/1
References: <36a77afb.5046977@m1> <epWKmN2R#GA.424@nih2naaa.prod2.compuserve.com> <O62Q38lS#GA.206@uppssnewspub05.moswest.msn.net> <78pcq0$16l$1@platane.wanadoo.fr>
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Good point, I didn't cover what happens when you use the Call keyword -- OK,
let's sum up with a code sample:

Sub Bar( x )
End Sub

Sub Baz( a, b )
End Sub

Function Foo( y )
End Function

z = 123
n = Foo(z)         ' legal, passes z by reference
n = Foo((z))       ' legal, passes z by reference
'n = Foo z         ' illegal, parens required
Foo z              ' legal, passes z by reference
Foo(z)             ' legal, passes z by value
'Call Foo z        ' illegal, parens required
Call Foo(z)        ' legal, passes z by reference
Call Foo((z))      ' legal, passes z by value
'n = Bar(z)        ' illegal, bar is not a function
Bar z              ' legal, passes z by reference
Bar(z)             ' legal, passes z by value
Call Bar(z)        ' legal, passes z by reference
Call Bar((z))      ' legal, passes z by value
Baz z, z           ' legal, passes z by reference
Baz (z), (z)       ' legal, passes z by reference
'Baz(z,z)          ' illegal, can't use parens
Call Baz(z, z)     ' legal, passes z by reference
Call Baz((z), (z)) ' legal, passes z by value
'Call Baz z, z     ' illegal, parens required


This is what we in the programming language business call "a big mess".
Unfortunately, we're stuck with it for backwards-compatibility reasons.

Eric



Theudrid <Theudrid@hotmail.com> wrote in message
news:78pcq0$16l$1@platane.wanadoo.fr...
>
> Eric Lippert (Microsoft Scripting Dev) a écrit dans le message ...
>  |Hi there,
>  |
>  |This is NOT a bug -- this is by design.  (Not very good design, in my
>  |opinion, but by design.)
>  |
>  |VBScript is compatible with VB, and VB has worked like this for many
 years
>  |now.  If you have a VB sub that takes a byref argument and you enclose
 the
>  |argument in parentheses, the argument is always passed by value.
 VBScript
>  |works exactly the same way.
>  |
>  |Eric
>
>
> Only if you forget the keyword "call"...
>
>