global variable or function?

[Melba23]

gil900,

 

But I think there are many who consider Local Static as Local

Then they should read the Help file:

 

The difference between Local and Static is variable lifetime. Local variables are only stored while the function is called and are visible only within the function in which they are declared; when the function returns, all its local variables are released. Static variables are likewise visible only in the function in which they are declared, but they continue to exist, retaining their last value, after the function finishes execution.

I sometimes wonder why we bother writing such a comprehensive Help file - a good proportion of the questions on the forum would not have been necessary if the posters had taken the time to read it carefully before posting. >

M23

[TheSaint]

 

1. If the variable is local then no, it will be destroyed when the function is returned from. If global, then I guess it's a case of do you want to remove what the variable is point to in memory.
2. AutoIt doesn't store datatypes like other languages, but an empty space is a single character, which is a byte plus the null terminator, so 2 bytes.

I think we, czardas and I have answered your questions.

That last perhaps, except ......

What I'm trying to ask, is that if I've declared a variable Global, and it holds a lot of data, is it advantageous to clear that data when it is no longer required, but the script is still running? Would it help, say in your circumstance, where you have other memory intensive program(s) running?

[Guest]

Melba23, I'm just saying that I would add this sentence (in red color) to his answer:

 

If the variable is local then not(as long it is not static),  it will be destroyed when the function is returned from. If global, then I guess it's a case of do you want to remove what the variable is point to in memory.

 

This is my point.
I completely understand what it is Static now..

Edited January 19, 2015 by Guest

[czardas]

That last perhaps, except ......

What I'm trying to ask, is that if I've declared a variable Global, and it holds a lot of data, is it advantageous to clear that data when it is no longer required, but the script is still running? Would it help, say in your circumstance, where you have other memory intensive program(s) running?

 

Absolutely!

Edited January 19, 2015 by czardas

[BrewManNH]

If you don't need what's in the variable later, and you want to free up the memory that the variable uses, you can clear it. This would be best for variables that hold a lot of data, or a large array.

[TheSaint]

Quite the contrary. Avoiding global variables and using more fuctions takes care of ever having to worry about scope.

Am I right in presuming you mean something like the following (simplistic version).

MsgBox(0, "Read Value", GuiCtrlRead($Input_1))

You are saying, that the value only exists in memory while it is read and returned, and then destroyed immediately?

So, it is better than.

Global $val

$val = GuiCtrlRead($Input_1)

MsgBox(0, "Read Value", $val)

[czardas]

It is true in this scenario, although readability is also key. Declaring a variable is not necessary here, but it can make it easier to understand the code when you read it.

Edited January 19, 2015 by czardas

[TheSaint]

I'm also presuming, that when I declare a variable - Global $var

and though it is empty at that point, it is still taking up significant memory space?

[guinness]

Yes it's better, because is there a need for $var afterwards? In that snippet no there isn't, so you're using the lowest possible scope in that snippet. If it was in a function you could get away with using local as well, as the variable would be destroyed once the function was returned from.

I think all this is in the help file and wiki.

[TheSaint]

It is true in this scenario, although readability is also key. Declaring a variable is not necessary here, but it can make it easier to understand the code.

Yes, but what is the recommended way?

[guinness]

I'm also presuming, that when I declare a variable - Global $var

and though it is empty at that point, it is still taking up significant memory space?

Yes, because AutoIt internally stores the variable name in a list (though I shan't be discussing the internals of AutoIt here).

Edited January 19, 2015 by guinness

[guinness]

Yes, but what is the recommended way?

In that example the first approach. But if you use the contents of the control again, then store in a variable (local) instead of reading it everytime. This is basic knowledge and common coding practice. What we're discussing relates to VB too, a language which I believe you're proficient in.

Edited January 19, 2015 by guinness

[TheSaint]

I think all this is in the help file and wiki.

I have read about this in the Help file, admittedly some time ago, and then just quick forays when I need a reminder of something. I could possible benefit from a re-read, but is it specific like my questions here?

I like the personal approach of picking multiple minds at once, and engaging in a discussion ... rather than a lonesome boring read. Anyway, you guys started it.

[czardas]

Yes, but what is the recommended way?

 

I don't think you can draw an exact line here. I ask myself, can I follow the code? I assume that if I can understand it, that others can too. If it looks totally mystifying then I break the code up into smaller chunks, often declaring more variables, adding comments and trying to solve my issue with understanding. On the other hand, if my code reads well and runs well, I remove variables at leisure.

Edit : spelling

Edited January 20, 2015 by czardas

[TheSaint]

What we're discussing relates to VB too, a language which I believe you're proficient in.

I wouldn't go as far as saying proficient ... I can use it (VB 6) if I have to ... I don't enjoy it much though. AutoIt is far more logical to my mind, and I consider myself far more proficient in AutoIt (if not anything new after v3.3.0.0).

Remember, I picked all my programming up, just like I picked up Html, by see and try and a little reading when necessary.

I never set out to become expert, only to do the things I needed programming for ... can't avoid learning something though.

EDIT

More VBA than just straight VB. Been many a year since I used straight VB. I still regularly work with VBA in Word and Excel .... talking Office 2003 here.

Edited January 19, 2015 by TheSaint

[guinness]

As well as czardas' approach, I also apply the rule of using Hungarian notation and one variable for one datatype, so you wouldn't catch me doing this $sName = 100. The reason I do this, or did this, is when I transitioned to C# it meant I was used to having variables hold a single datatype.

Edited January 19, 2015 by guinness

[Guest]

 

I have two new questions here

SomeFunc()
Func SomeFunc()
    $var = 1
    $var ; <- Why the script does not crash here?
    ConsoleWrite($var&@CRLF) ; <- It does not even chage the variable to "" so what is the point of write only the variable? What it gives?
EndFunc
MsgBox(0,'','WORKING!!')

[guinness]

 

 

I have two new questions here

SomeFunc()
Func SomeFunc()
    $var = 1
    $var ; <- Why the script does not crash here?
    ConsoleWrite($var&@CRLF) ; <- It does not even chage the variable to "" so what is the point of write only the variable? What it gives?
EndFunc
MsgBox(0,'','WORKING!!')

Really? I can't test right now but I have a heard time believe that Au3Check doesn't throw an error nor does the interpreter.

[TheSaint]

P.S. Like I said earlier, Questions and Observations. Don't take my questions as me not being cognizant of the likely answer. It is a way of painting an overall picture, and getting responses that you may not think to give ordinarily. Apologies if it feels like going back to pre-school at times, but as I found with VB, too many programmers presume on what you know, and leave things out ... sometimes very necessary things. Help and the Wiki can be the same.

I've been known to spend a whole wasted day or two on crap like that, when I could have been clued in in an instant.

Edited January 19, 2015 by TheSaint

[Guest]

Really? I can't test right now but I have a heard time believe that Au3Check doesn't throw an error nor does the interpreter.

 

Yes, Really

Au3Check doesn't throw an error and also the interpreter not.

Tested on v3.3.10.2

And this works as expected if I delete the line:

$var = 1

It seems that I found interesting bug

Edited January 19, 2015 by Guest