Dim - Explination

[ligenza]

Nothing to see here, please move along.

Edited September 30, 2005 by ligenza

[Shibuya]

if that variable is used outside a local scope, it becomes a global variable and takes/changes the value assigned when declared in the global scope, it will not be reinitialised

Edited September 30, 2005 by Shibuya

[Valik]

Easiest explained by code:

Global $variable = "Foo"
MsgBox(0, "", "Printfs 'Foo'=" & $variable)
function()
MsgBox(0, "", "Printfs 'Bar'=" & $variable)

Func function()
    Dim $variable = "Bar"; This is NOT a new local variable
EndFunc

Compared to this which uses explicit scope qualification (Local/Global can be used to dim arrays, too):

Global $variable = "Foo"
MsgBox(0, "", "Printfs 'Foo'=" & $variable)
function()
MsgBox(0, "", "Printfs 'Foo'=" & $variable)

Func function()
    Local $variable = "Bar"; Hide the variable at global scope
    MsgBox(0, "", "Printfs 'Bar'=" & $variable)
EndFunc

[ligenza]

Easiest explained by code:

Global $variable = "Foo"
MsgBox(0, "", "Printfs 'Foo'=" & $variable)
function()
MsgBox(0, "", "Printfs 'Bar'=" & $variable)

Func function()
    Dim $variable = "Bar"; This is NOT a new local variable
EndFunc

Compared to this which uses explicit scope qualification (Local/Global can be used to dim arrays, too):

Global $variable = "Foo"
MsgBox(0, "", "Printfs 'Foo'=" & $variable)
function()
MsgBox(0, "", "Printfs 'Foo'=" & $variable)

Func function()
    Local $variable = "Bar"; Hide the variable at global scope
    MsgBox(0, "", "Printfs 'Bar'=" & $variable)
EndFunc

Thanks.

Can't I just do this and get the same result? I'm not seeing the need for Dim.

Global $variable = "Foo"
MsgBox(0, "", "Printfs 'Foo'=" & $variable)
function()
MsgBox(0, "", "Printfs 'Bar'=" & $variable)

Func function()
;Dim $variable = "Bar"; This is NOT a new local variable
        $variable = "Bar"
EndFunc

Edited September 30, 2005 by ligenza

[Shibuya]

So it is a local unless used as a global?

if the variable appears anywhere out of the local scope, it becomes a global variable

take this for example:

Func Test1()

Dim $var = "Tesing";this variable is declared inside a function, which is supposed to be local
Msgbox(0, "", $var)

EndFunc

Func Test2()

Msgbox(0, "", $var); now the variable is being used outside Test1(), becomes global

EndFunc

so when Test2() is called, the output will be "Testing", even the variable is not declared and assigned a value inside the function

[Valik]

Yes, your example is the same. However, Dim predates Global/Local and as such it has some... weird scoping rules. IMO, Dim should be deprecated in favor of the explicit qualifiers Local/Global but I've never pushed for this.

[Shibuya]

i suppose it's convenient?

i've never used "global" or "local" so far, only dim

[ligenza]

i suppose it's convenient?

i've never used "global" or "local" so far, only dim

Yeah I suppose. Thanks for all the feedback.