sub or function

[Roland Hall]

Re: sub or function

"CJM" <cjmnews04@news group.nospam> wrote in message
news:%230eGH7Mm FHA.3312@tk2msf tngp13.phx.gbl. ..
:
: "Roland Hall" <nobody@nowhere > wrote in message
: news:OZjYjXHmFH A.2180@TK2MSFTN GP15.phx.gbl...
: >
: > Are you saying a passed variable to a sub, if the value changes will
: > change
: > the value of a global variable? Isn't that only true if it's passed
: > ByRef?
:
: However, if you were talking about a Global variable, there would be no
: reason to pass it as a parameter because it already accessible because it
: is...er.. Global!
:
: I hope this hasn't muddied the water any further!

No problem.

What if it is passed from another sub/function?

function myincfunc(x)
myincfunc= x + 1
end function

sub tomorrow(x)
dim thisday, nextday
thisday = x
nextday = myincfunc(thisd ay)
Response.Write "Tomorrow's secret number is: " & nextday
end sub

dim x
x = 4
tomorrow x

x is global
sub x is byRef, assigned byVal to thisday, passed byRef to func x,
incremented and returned

Did any initial variables change?

--
Roland Hall
/* This information is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of merchantability
or fitness for a particular purpose. */
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[Roland Hall]

Re: sub or function

"Bob Lehmann" wrote in message news:efYuPqOmFH A.3288@TK2MSFTN GP09.phx.gbl...
: >> Isn't that only true if it's passed ByRef?
: The default is ByRef in VBScript. So, unless you you explicitly pass it
: ByVal, it will be changed.

I know it [global variable] changes because I've been caught with my pants
down on this issue before and had to use ByVal to get out of it but it was a
global variable I was passing, which was not required. A local variable
will also change if passed byRef to another sub/function?

--
Roland Hall
/* This information is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of merchantability
or fitness for a particular purpose. */
Technet Script Center - http://www.microsoft.com/technet/scriptcenter/
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MSDN Library - http://msdn.microsoft.com/library/default.asp

[CJM]

Re: sub or function

Problem spotted - I'm an idiot.

Of course, when we run test1() it is updating the variable y.

Modified code:

<%@ Language="VBScr ipt" %>
<%

Option Explicit

Dim x

function test1(x)
x = x + 10
test1 = x
End function

function test2()
x = x + 1
test2 = x
end function

sub test0()
dim y, z

y = x

z = test1(y)

response.Write "Test1.1: " & z & "<br>"
response.Write "x = " & x & "<br>"
response.Write "y = " & y & "<br>"

z = test1(y)

response.Write "Test1.2: " & z & "<br>"
response.Write "x = " & x & "<br>"
response.Write "y = " & y & "<br>"

z = test2()

response.Write "Test2.1: " & z & "<br>"
response.Write "x = " & x & "<br>"
response.Write "y = " & y & "<br>"

z = test2()

response.Write "Test2.2: " & z & "<br>"
response.Write "x = " & x & "<br>"
response.Write "y = " & y & "<br>"
end sub

x = 0

response.Write "Pass1: <br>"
test0()

response.Write "<br>Pass2: <br>"
test0()
%>

[Chris Hohmann]

Re: sub or function

"Roland Hall" <nobody@nowhere > wrote in message
news:uc1wfpQmFH A.3916@TK2MSFTN GP10.phx.gbl...[color=blue]
> A local variable
> will also change if passed byRef to another sub/function?[/color]

Yes.

<%
Option Explicit
Function Foo(parameter_b y_ref)
Dim return_value, local_variable
local_variable = parameter_by_re f
return_value = Bar(local_varia ble)
Foo = local_variable
End Function

Function Bar(parameter_b y_ref)
parameter_by_re f = parameter_by_re f + 1
Bar = "Hello World"
End Function

Response.Write Foo(4)
%>

[Chris Hohmann]

Re: sub or function

"CJM" <cjmnews04@news group.nospam> wrote in message
news:uhw6oBRmFH A.3828@TK2MSFTN GP12.phx.gbl...[color=blue]
>
> "Roland Hall" <nobody@nowhere > wrote in message
> news:%23LaytnQm FHA.2060@tk2msf tngp13.phx.gbl. ..[color=green]
>>
>> What if it is passed from another sub/function?
>>
>> function myincfunc(x)
>> myincfunc= x + 1
>> end function
>>
>> sub tomorrow(x)
>> dim thisday, nextday
>> thisday = x
>> nextday = myincfunc(thisd ay)
>> Response.Write "Tomorrow's secret number is: " & nextday
>> end sub
>>
>> dim x
>> x = 4
>> tomorrow x
>>
>> x is global
>> sub x is byRef, assigned byVal to thisday, passed byRef to func x,
>> incremented and returned
>>
>> Did any initial variables change?[/color]
>
> AFAIK...
>
> The x in myincfunc is local to the function - it is not the same as the
> global variable x. So in this instance the global variable x does not
> change.
>
> If we change the function to:
>
> function myincfunc()
> myincfunc= x + 1
> end function
>
> ...so there is no incoming parameter, x the global variable x would be
> incremented each time the function is called.
>
> [10 minute interlude...]
>
> Right! I've created a test page. It kind of proved what I was saying with
> one exception which I dont understand!
>
> Here's the code:
>
> <%@ Language="VBScr ipt" %>
> <%
>
> Option Explicit
>
> Dim x
>
> function test1(x)
> x = x + 10
> test1 = x
> End function
>
> function test2()
> x = x + 1
> test2 = x
> end function
>
> sub test0()
> dim y, z
>
> y = x
>
> z = test1(y)
>
> response.Write "Test1.1: " & z & "<br>"
> response.Write "x = " & x & "<br>"
>
> z = test1(y)
>
> response.Write "Test1.2: " & z & "<br>"
> response.Write "x = " & x & "<br>"
>
> z = test2()
>
> response.Write "Test2.1: " & z & "<br>"
> response.Write "x = " & x & "<br>"
>
> z = test2()
>
> response.Write "Test2.2: " & z & "<br>"
> response.Write "x = " & x & "<br>"
> end sub
>
> x = 0
>
> response.Write "Pass1: <br>"
> test0()
>
> response.Write "<br>Pass2: <br>"
> test0()
> %>
>
> And here are my results:
>
> Pass1:
> Test1.1: 10
> x = 0
> Test1.2: 20
> x = 0
> Test2.1: 1
> x = 1
> Test2.2: 2
> x = 2
>
> Pass2:
> Test1.1: 12
> x = 2
> Test1.2: 22
> x = 2
> Test2.1: 3
> x = 3
> Test2.2: 4
> x = 4
>
> It all behaves as I would expect, except for test 1.2. In these cases, I
> would expect the returned result to be the same as Test1.1 UNLESS the
> global variable x is indeed being updated. However, we can see from the
> next line that x only appears to be updated by the test2 function.
>
> 3 Possibilities:
> - A Bug: possible but doubtful
> - A cock-up in my code: usually very likely
> - Correct behaviour though for unknown reasons: is this the case?
>
>
> Any thoughts?
>
> Chris[/color]

Everything is behaving as it should. In test 1.1 the a _reference_ to the
local y variable in test0 is being passed to the test1 function. Since it's
a reference, the local y variable in test0 gets incremented to 10. When the
local y variable is pass by _reference_ to the test1 function for a second
time in test 1.2, it is again incremented by 10, resulting in a value of 20.
Basically, all parameters, regardless of scope, are passed by reference
unless explicitly told otherwise.

[Chris Hohmann]

Re: sub or function

"Chris Hohmann" <nospam@thankyo u.com> wrote in message
news:OVtylNRmFH A.2916@TK2MSFTN GP14.phx.gbl...[color=blue]
> In test 1.1 the a _reference_ to the local y variable in test0 is being
> passed to the test1 function.[/color]

That should read:

In test 1.1 a _reference_ to the ...

[Roland Hall]

Re: sub or function

"CJM" wrote in message news:OoA0ZFRmFH A.1372@TK2MSFTN GP10.phx.gbl...
: Problem spotted - I'm an idiot.

Hardly...

: Of course, when we run test1() it is updating the variable y.
:
: Modified code:
:
: <%@ Language="VBScr ipt" %>
: <%
:
: Option Explicit
:
: Dim x
:
: function test1(x)
: x = x + 10
: test1 = x
: End function
:
: function test2()
: x = x + 1
: test2 = x
: end function
:
: sub test0()
: dim y, z
:
: y = x
:
: z = test1(y)
:
: response.Write "Test1.1: " & z & "<br>"
: response.Write "x = " & x & "<br>"
: response.Write "y = " & y & "<br>"
:
: z = test1(y)
:
: response.Write "Test1.2: " & z & "<br>"
: response.Write "x = " & x & "<br>"
: response.Write "y = " & y & "<br>"
:
: z = test2()
:
: response.Write "Test2.1: " & z & "<br>"
: response.Write "x = " & x & "<br>"
: response.Write "y = " & y & "<br>"
:
: z = test2()
:
: response.Write "Test2.2: " & z & "<br>"
: response.Write "x = " & x & "<br>"
: response.Write "y = " & y & "<br>"
: end sub
:
: x = 0
:
: response.Write "Pass1: <br>"
: test0()
:
: response.Write "<br>Pass2: <br>"
: test0()
: %>

Great example. Very helpful. Thanks.

--
Roland Hall
/* This information is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of merchantability
or fitness for a particular purpose. */
Technet Script Center - http://www.microsoft.com/technet/scriptcenter/
WSH 5.6 Documentation - http://msdn.microsoft.com/downloads/list/webdev.asp
MSDN Library - http://msdn.microsoft.com/library/default.asp

[Roland Hall]

Re: sub or function

"Chris Hohmann" wrote in message
news:e2tagFRmFH A.2080@TK2MSFTN GP14.phx.gbl...
: "Roland Hall" <nobody@nowhere > wrote in message
: news:uc1wfpQmFH A.3916@TK2MSFTN GP10.phx.gbl...
: > A local variable
: > will also change if passed byRef to another sub/function?
:
: Yes.
:
: <%
: Option Explicit
: Function Foo(parameter_b y_ref)
: Dim return_value, local_variable
: local_variable = parameter_by_re f
: return_value = Bar(local_varia ble)
: Foo = local_variable
: End Function
:
: Function Bar(parameter_b y_ref)
: parameter_by_re f = parameter_by_re f + 1
: Bar = "Hello World"
: End Function
:
: Response.Write Foo(4)
: %>

Also helpful... thanks.

This was very interesting to see:

Option Explicit
Function Foo(parameter_b y_ref)
Dim return_value, local_variable
local_variable = parameter_by_re f
Bar(local_varia ble)
Foo = local_variable
End Function

sub Bar(parameter_b y_ref)
parameter_by_re f = parameter_by_re f + 1
End sub

wscript.echo Foo(4)

Result: 4

Option Explicit
Function Foo(parameter_b y_ref)
Dim return_value, local_variable
local_variable = parameter_by_re f
Bar local_variable
Foo = local_variable
End Function

sub Bar(parameter_b y_ref)
parameter_by_re f = parameter_by_re f + 1
End sub

wscript.echo Foo(4)

Result: 5

--
Roland Hall
/* This information is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of merchantability
or fitness for a particular purpose. */
Technet Script Center - http://www.microsoft.com/technet/scriptcenter/
WSH 5.6 Documentation - http://msdn.microsoft.com/downloads/list/webdev.asp
MSDN Library - http://msdn.microsoft.com/library/default.asp

[Chris Hohmann]

Re: sub or function

"Roland Hall" <nobody@nowhere > wrote in message
news:eEpSNoRmFH A.3336@tk2msftn gp13.phx.gbl...[color=blue]
> "Chris Hohmann" wrote in message
> news:e2tagFRmFH A.2080@TK2MSFTN GP14.phx.gbl...
> : "Roland Hall" <nobody@nowhere > wrote in message
> : news:uc1wfpQmFH A.3916@TK2MSFTN GP10.phx.gbl...
> : > A local variable
> : > will also change if passed byRef to another sub/function?
> :
> : Yes.
> :
> : <%
> : Option Explicit
> : Function Foo(parameter_b y_ref)
> : Dim return_value, local_variable
> : local_variable = parameter_by_re f
> : return_value = Bar(local_varia ble)
> : Foo = local_variable
> : End Function
> :
> : Function Bar(parameter_b y_ref)
> : parameter_by_re f = parameter_by_re f + 1
> : Bar = "Hello World"
> : End Function
> :
> : Response.Write Foo(4)
> : %>
>
> Also helpful... thanks.
>
> This was very interesting to see:
>
> Option Explicit
> Function Foo(parameter_b y_ref)
> Dim return_value, local_variable
> local_variable = parameter_by_re f
> Bar(local_varia ble)
> Foo = local_variable
> End Function
>
> sub Bar(parameter_b y_ref)
> parameter_by_re f = parameter_by_re f + 1
> End sub
>
> wscript.echo Foo(4)
>
> Result: 4
>
> Option Explicit
> Function Foo(parameter_b y_ref)
> Dim return_value, local_variable
> local_variable = parameter_by_re f
> Bar local_variable
> Foo = local_variable
> End Function
>
> sub Bar(parameter_b y_ref)
> parameter_by_re f = parameter_by_re f + 1
> End sub
>
> wscript.echo Foo(4)
>
> Result: 5[/color]

In your first example, this line:

Bar(local_varia ble)

is interpreted by the parser as passing the expression "(local_variabl e)" to
the Bar procedure. The parenthesis in this case causes the parser to
interpret the argument being passed to the Bar procedure as a complex
expression instead of a simple variable reference. As such, what's being
passed in this case is a reference to the implicit/pseudo variable used to
hold the result of evaluating the "(local_variabl e)" expression. It would be
akin to this call:

Bar local_variable + 1

Or this one:

Bar (local_variable + 1)

Or this one:

Bar 22/7

You get the idea.

[CJM]

Re: sub or function


"Roland Hall" <nobody@nowhere > wrote in message[color=blue]
>
> Great example. Very helpful. Thanks.
>[/color]


No probs... In return, would you please do the Despatch Planning report that
I was supposed to be doing while I did this?

Cheers

Chris

[Roland Hall]

Re: sub or function

"CJM" <cjmnews04@yaho o.co.uk> wrote in message
news:3lf6kcF11n 7t8U1@individua l.net...
:
: "Roland Hall" <nobody@nowhere > wrote in message
: >
: > Great example. Very helpful. Thanks.
:
: No probs... In return, would you please do the Despatch Planning report
that
: I was supposed to be doing while I did this?

Piece of cake. When would you like it completed?

--
Roland Hall
/* This information is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of merchantability
or fitness for a particular purpose. */
Technet Script Center - http://www.microsoft.com/technet/scriptcenter/
WSH 5.6 Documentation - http://msdn.microsoft.com/downloads/list/webdev.asp
MSDN Library - http://msdn.microsoft.com/library/default.asp

[Roland Hall]

Re: sub or function

"Chris Hohmann" wrote in message
news:uMA6y7RmFH A.3316@TK2MSFTN GP14.phx.gbl...
: "Roland Hall" <nobody@nowhere > wrote in message
: news:eEpSNoRmFH A.3336@tk2msftn gp13.phx.gbl...
: > "Chris Hohmann" wrote in message
: > news:e2tagFRmFH A.2080@TK2MSFTN GP14.phx.gbl...
: > : "Roland Hall" <nobody@nowhere > wrote in message
: > : news:uc1wfpQmFH A.3916@TK2MSFTN GP10.phx.gbl...
: > : > A local variable
: > : > will also change if passed byRef to another sub/function?
: > :
: > : Yes.
: > :
: > : <%
: > : Option Explicit
: > : Function Foo(parameter_b y_ref)
: > : Dim return_value, local_variable
: > : local_variable = parameter_by_re f
: > : return_value = Bar(local_varia ble)
: > : Foo = local_variable
: > : End Function
: > :
: > : Function Bar(parameter_b y_ref)
: > : parameter_by_re f = parameter_by_re f + 1
: > : Bar = "Hello World"
: > : End Function
: > :
: > : Response.Write Foo(4)
: > : %>
: >
: > Also helpful... thanks.
: >
: > This was very interesting to see:
: >
: > Option Explicit
: > Function Foo(parameter_b y_ref)
: > Dim return_value, local_variable
: > local_variable = parameter_by_re f
: > Bar(local_varia ble)
: > Foo = local_variable
: > End Function
: >
: > sub Bar(parameter_b y_ref)
: > parameter_by_re f = parameter_by_re f + 1
: > End sub
: >
: > wscript.echo Foo(4)
: >
: > Result: 4
: >
: > Option Explicit
: > Function Foo(parameter_b y_ref)
: > Dim return_value, local_variable
: > local_variable = parameter_by_re f
: > Bar local_variable
: > Foo = local_variable
: > End Function
: >
: > sub Bar(parameter_b y_ref)
: > parameter_by_re f = parameter_by_re f + 1
: > End sub
: >
: > wscript.echo Foo(4)
: >
: > Result: 5
:
: In your first example, this line:
:
: Bar(local_varia ble)
:
: is interpreted by the parser as passing the expression "(local_variabl e)"
to
: the Bar procedure. The parenthesis in this case causes the parser to
: interpret the argument being passed to the Bar procedure as a complex
: expression instead of a simple variable reference. As such, what's being
: passed in this case is a reference to the implicit/pseudo variable used to
: hold the result of evaluating the "(local_variabl e)" expression. It would
be
: akin to this call:
:
: Bar local_variable + 1
:
: Or this one:
:
: Bar (local_variable + 1)
:
: Or this one:
:
: Bar 22/7
:
: You get the idea.

Ya, I got it. I just never knew the ( ) were such an issue.

--
Roland Hall
/* This information is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of merchantability
or fitness for a particular purpose. */
Technet Script Center - http://www.microsoft.com/technet/scriptcenter/
WSH 5.6 Documentation - http://msdn.microsoft.com/downloads/list/webdev.asp
MSDN Library - http://msdn.microsoft.com/library/default.asp