scope variable local global

[carlomagno]

Hi all

I have this code

Opt("MustDeclareVars", 1)

local $var1 = "test"

foo()

func foo()

ConsoleWrite("var1: " & $var1 & @LF)

EndFunc

Because I can show the value of $var1 inside function foo()?

I think that if $var1 is a local variable should not propagate within func

and in this case I should receive an error.

What do you think?

[guinness]

This should be Global, this is an example where a variable is Local but is created in what could be classed as 'Global space' but the variable isn't used anywhere else.

Global $vVar = "Example" ; Used else in a Function.

Local $sString = "String" ; Used no where else but here.
ConsoleWrite("sString: " & $sString & @CRLF)

Example()

Func Example()
    ConsoleWrite("vVar: " & $vVar & @CRLF)
EndFunc   ;==>Example

[water]

All variables defined in the calling function are always accessible by the called function unless you defined a local variable in the called function with the same name.

Please check the help file: Language Reference - Variables, Scope.

Edited March 27, 2012 by water

[water]

But $sString can be accessed in the called function. I think the OP wonders why he can access a Local variable in a called function.

This example shows both values either defined as Global or Local:

Global $vVar = "Example" ; Used else in a Function.

Local $sString = "String" ; Used no where else but here.
ConsoleWrite("sString: " & $sString & @CRLF)

Example()

Func Example()
    ConsoleWrite("vVar: " & $vVar & @CRLF)
    ConsoleWrite("sString: " & $sString & @CRLF)
EndFunc   ;==>Example

Edited March 27, 2012 by water

[guinness]

Weird because I would've thought $sString can't be seen in the Example() function. But logically speaking the variable he declared should be Global regardless of the fact declaring it as Local has the same effect.

Edited March 27, 2012 by guinness

[water]

Weird? Normal behaviour I would say.

According to the help file: "If you declare a variable inside a function it is in Local scope and can only be used within that same function." Inside this function includes all functions called by the function. Even the main script is regarded to be a function in this case so a local variable can be "seen" in all called functions until ... see above.

[guinness]

I thought it had the same affect as this, I've wrapped the top part in a function called 'Main'. Also I'm using the advice Valik provided a while back ()

Global $vVar = "Example"

Main()

Func Main()
    Local $sString = "String"
    ConsoleWrite("sString: " & $sString & @CRLF)
    Example()
EndFunc   ;==>Main

Func Example()
    ConsoleWrite("vVar: " & $vVar & @CRLF)
EndFunc   ;==>Example

[water]

The OP thought that $sString would not be accessible in function Example. A local variable is always accessible in the function where it is defined plus all functions called from this function.

[guinness]

You mean like this?

Global $vVar = "Example"

Main()

Func Main()
    Local $sString = "String"
    ConsoleWrite("sString: " & $sString & @CRLF)
    Example()
EndFunc   ;==>Main

Func Example()
    ConsoleWrite("vVar: " & $vVar & @CRLF)
    ConsoleWrite("sString: " & $sString & @CRLF) ; Creates undefined error.
EndFunc   ;==>Example

[water]

OK, seems I learned something new today - regarding AutoIt and how I do/don't understand English

After re-reading the help file a few times I understand that it exactly describes how AutoIt works.

I have to admit that I'm a bit confused that AutoIt defines the scope of a variable by a keyword PLUS where it is declared.

Why is a local variable defined outside any function a global variable? But defined inside a function it is a local variable. Strange ...

[carlomagno]

All variables defined in the calling function are always accessible by the called function unless you defined a local variable in the called function with the same name.

Please check the help file: Language Reference - Variables, Scope.

This is the response that clarifies everything

thanks

[guinness]

Why is a local variable defined outside any function a global variable? But defined inside a function it is a local variable. Strange ...

This is what I don't understand either.

[carlomagno]

The OP thought that $sString would not be accessible in function Example

I would have liked it to be so ...

[water]

All variables defined in the calling function are always accessible by the called function unless you defined a local variable in the called function with the same name.

But unfortunately this explanation is wrong.

A local variable can only be accessed by all called functions when it is defined in the "main" script (and therefore implicitely defined as global).

Edited March 27, 2012 by water

[carlomagno]

But unfortunately this explanation is wrong.

A local variable can only be accessed by all called functions when it is defined in the "main" script (and therefore implicitely defined as global).

ok

i can do this

Main()

Func Main()

local $foo = "test"

Func1($foo)

ConsoleWrite("$foo: " & $foo & @LF)

EndFunc

func Func1($foo)

$foo = "example"

ConsoleWrite("$foo: " & $foo & @LF)

EndFunc

[guinness]

ok

i can do this

Main()

Func Main()

local $foo = "test"

Func1($foo)

ConsoleWrite("$foo: " & $foo & @LF)

EndFunc

func Func1($foo)

$foo = "example"

ConsoleWrite("$foo: " & $foo & @LF)

EndFunc

This is how I would do it.

[Melba23]

guinness and water,

This is my understanding from using AutoIt - I do not have access to the core code (nor would I understand it if I did! ):

If not otherwise specified in the code, variables are scoped accoding to their location: Global if in main script; Local if in a function. In the Global case the variable is accessible throughout the script; If Local it is available in that function only and can only be referenced elsewhere if passed as a parameter.

If specified in the code as Global, the variable is Global regardless of where it is - although AU3Check will throw a warning if you do it in a function. If specified as Local the variable behaves as in the non-specified case (Global if in the main script; Local if in a function) - note that even if there is already a Global variable of the same name, the Local variable will be used.

As to why a Local variable in the main script is treated as Global - you need to ask a Dev. Personally I would like to see them as Local to the main script, but I imagine it is a sop to lazy coders who do not scope variables at all. I seem to remember Valik mentioning this some time ago in another discussion, but I cannot find the relevant post.

M23

[guinness]

As to why a Local variable in the main script is treated as Global - you need to ask a Dev. Personally I would like to see them as Local to the main script, but I imagine it is a sop to lazy coders who do not scope variables at all. I seem to remember Valik mentioning this some time ago in another discussion, but I cannot find the relevant post.

I would like this too as then it would make sense why to use Local over Global in this instance. Do you mean the link I post above?

[water]

Melba,

thanks for clarifying! That's how I see it (now) too.

I never came across this "problem" before due to the way I code my scripts.

[Melba23]

guinness,

Yes, that was exactly the discussion to which I was referring.

water,

Since I learnt about "scope" I make sure that in my serious scripts (as opposed to short examples) I declare all my variables explicitly - so I do not have "problems" either.

M23