Good coding practices in AutoIt

[BrewManNH]

Why not just declare global scope variables Global, and leave it at that?

[AZJIO]

guinness

Of the examples I realized that such variables should not be. Any code begins with a main() function

[guinness]

Why not just declare global scope variables Global, and leave it at that?

I've explained numerous times and provided references to back my claims. Oh and aren't Globals deemed bad anyway? So wrapping it in a function would be a better choice.

guinness

Of the examples I realized that such variables should not be. Any code begins with a main() function

Did you look at IsHWnd now? Edited February 17, 2013 by guinness

[guinness]

The whole thread is intended for good coding practice.

[czardas]

Then stick to it. Avoid Globals. If you declare a local variable in global scope, that is bad practice according to Valik. I tend to agree with him on this. See my

Edited February 17, 2013 by czardas

[BrewManNH]

The whole thread is intended for good coding practice.

In AutoIt, which doesn't follow the same rules as other languages, so it should be focused only on AutoIt.

[AZJIO]

czardas

Your previous post I did not understand. BTW post Valik also not understood.

Edited February 17, 2013 by AZJIO

[guinness]

Well, in general but exceptions being made for when AutoIt breaks the norm.

I'm not trying to sway you or czardas, just put across what I had learnt from one of the developers of AutoIt.

[acidman]

You know guys, most of you will most likely not agree with me, but you can try it this way, maybe it wil work for you too...

Only declare Local vars inside a function

But when declaring global vars I like to do this...

Global $string, "interger

Test1()

Func Test1()

$String = " bloooooooooh"

$Interger = 98

.....

......

Endfunc

[guinness]

Sorry ac1dm4n, but we understand how to declare variables, this isn't the issue we're debating about I'm afraid.

[AZJIO]

I suspect that all the code is in the local scope. In the global scope are internal variables AutoIt3.

It is you want to say?

[czardas]

I don't think the Help File needs to have all examples set in the context of some main script. They should clearly run and stick to correct syntax. To some degree I see this as a separate issue from good coding practice: the help file being a teaching aid to demonstrate the use of various functions in a clear and precise way.

I think the main confusion here is caused by the fact that we are discussing the difference between appropriate scope, actual scope and explicit declaration. These are three different things. Here is where the water seems to get a bit muddy.

Edited February 17, 2013 by czardas

[czardas]

czardas

Your previous post I did not understand. BTW post Valik also not understood.

I mean if a variable does not need to be global, then it's better to declare it inside a function. If the variable needs to be global, then do not declare it inside a function. It's the simplified version of

Edit

I have since amended my post and tried to make my meaning clearer.

Just waiting for someone like Valik or trancexx to come along now and shatter my illusions.

Edited February 17, 2013 by czardas

[acidman]

Stringreplace("Some times I write a bunch of nonsense when I Get high", "Some times I write a bunch of nonsense when I Get high", "Sometimes I wonder by myself; how can folks write such crap, then I realize i few days later it was actually my comment")

[MvGulik]

@guinness

Are you planning to document this "Local declaration use at root level" some more at the wiki ?

I think it would not be a bad idea.

Yes or No will do.

[czardas]

If this requires documentation, I think it should be kept to a side comment. Perhaps something like:

Strictly speaking, local scope implies local to the current scope. Therefore, if you use the local keyword to declare a variable outside any function, it will inherit all the attributes of a global variable - i.e. be accessible to the whole script.

I think that says enough about the subject, without getting into complications about appropriate usage.

Edited February 17, 2013 by czardas

[guinness]

@guinness

Are you planning to document this "Local declaration use at root level" some more at the wiki ?

I think it would not be a bad idea.

Yes or No will do.

No.

[jaberwacky]

According to the book Code Complete these are some compelling reasons to avoid global scope. Most of these relate to information hiding in some way or another. A variable that is global is available to functions which may never need to have access to that variable.

Most of these are relevant to AutoIt and others are not.

* Inadvertent changes to global data. - "You might change the value of a global variable in one place and mistakenly think that it had remained unchanged somewhere else. Such a problem is known as a 'side effect'."

Reducing side effects is also achieved by having functions perform one task and perform it well. Also, functions should not modify global data. They also should be referentially transparent. Basically, a function should only operate on data which is passed through its parameters. Additionally, every time a function is called with the same arguments it should return the same result every time. So, avoid using random numbers, time and date functions and avoid asking for user input within functions.

* Bizarre and exciting aliasing problems with global data. - "'Aliasing' refers to calling the same variable by two or more different names."

* Re-entrant code problems with global data. - "Code that can be entered by more than one thread of control is becoming increasingly common. Multithreaded code creates the possibility that global data will be shared not only among routines, but among different copies of the same program."

* Code reuse hindered by global data. - "Ideally, you'd be able to lift out a single routine or class, plug it into another program, and continue merrily on your way. Global data complicates the picture."

I've encountered this problem with code that I've tried to reuse in my own scripts.

* Uncertain initialization-order issues with global data. - "The order in which data is initialized among different 'translation units' (files) is not defined in some languages."

* Modularity and intellectual manageability damaged by global data. - "The essence of creating programs that are larger than a few hundred lines of code is managing complexity. The only way you can intellectually manage a large program is to break it into pieces so that you only have to think about one part at a time."

edit: forgot a bullet point

Edited February 17, 2013 by jaberwocky6669

[czardas]

And having multple constants declaring the same value is not the only problem, there are a lot of flags which are pre-set combinations too:

A problem when you add them together yes, but otherwise a very intriguing feature.

[guinness]

I have an idea that I came up with whilst walking around the city today about eliminating 76.87% of Global variable usage in AutoIt. I will post an example later on this evening.

Edited February 18, 2013 by guinness