Good coding practices in AutoIt

[guinness]

Why didn't you say this to Valik then?

Edited September 4, 2015 by guinness

[czardas]

Well in normal circumstances I would agree, but this thread is about pointing out mistakes and providing users with the right approach to coding.

Declaring variables in the scope in which they are used is the correct approach. Using local to an undefined scope is perhaps bad design planning, or a lazy catch all approach.

Edited February 17, 2013 by czardas

[BrewManNH]

Because I've learned a lot more since that thread, and my confidence in my stand is greater than it was 2 years ago.

Everything Valik stated is correct, but doesn't really apply to AutoIt with its limited scoping of variables. If he had changed the scoping of variables, even then it wouldn't have made much sense because Local doesn't make Globals local except for semantics. Sure it's "Local" to the script, but it's still a global, it's not any clearer to declare it "local" to its scope to being able to follow the script.

[guinness]

I'm sure Valik was thinking about AutoIt when he made that statement as it wasn't the first time he said it, since he pointed it out to me in the MVP Forum when I started on the help file.

[MvGulik]

Links please (If you got them, use them.)

Not that it matters of course, but I don't like local variable declarations at global/root level either. (given the current two variable scopes.)

Please read >>

Mmm. Is that actually being planed?

[czardas]

From

When I first started helping out with changing the Help file this was the first thing I did, changing the scope from Local to Global. Valik pointed out and quite rightly so that despite the variable happening to be Global scope it's Local to the current scope. This is considered bad programming practice otherwise.

What is considered bad coding practice otherwise (as in what otherwise)? I am not privy to the discussions in the MVP forum. Perhaps you care to elaborate. I'm keen to learn something new.

Global should only be used if a variable truly needs to be Global - that is accessible from more than one function and not passed as a parameter.

I read this to mean:

Global should only be used if a variable truly needs to be Global - that is accessible from more than one function (being required) and not passed as a parameter.

I don't read it to mean explicitly declare globals with the Local keyword. The fact it is possible to do so is not the issue. I suspect that you were making unecessary changes to the help file, but there could be more to it than that, which is clearly what you suggest. So far I haven't figured out what else that might be.

Edited February 17, 2013 by czardas

[guinness]

Links please (If you got them, use them.)

I have.

[guinness]

I am not privy to the discussions in the MVP forum. Perhaps you care to elaborate. I'm keen to learn something new.

Generally speaking these are for MVP eyes only, but to cut a long story short, Valik picked up on my svn commits when I started to change the examples that use Local to Global. What he said to BrewManNH is a shortened version of what he said to me.

[czardas]

I thought he didn't want you to do unecessary work, when there's so much else to do. Don't change Local to Global in the help file unless it's a mistake. The reason being given in the post you linked to. If I'm wrong about this, then I hold my hands up. So far I don't see any evidence to the contrary. I think the wording in the link should be interpreted strictly to mean nothing more than it says.

Edited February 17, 2013 by czardas

[guinness]

No, he didn't say that at all. I changed the example IsHWnd to what you see below, Valik's response to me was...

Think about the code. Is the variable really global? No, it's not. It's Local to the current scope. The current Scope happens to be the global Scope but that doesn't mean the variable should be declared as global. That's bad programming practice.

Run("notepad.exe")
Global $hWnd = WinGetHandle("[CLASS:Notepad]") ; This was Local beforehand.
If IsHWnd($hWnd) Then
    MsgBox(4096, "", "It's a valid HWND")
Else
    MsgBox(4096, "", "It's not an HWND")
EndIf

[BrewManNH]

In this instance I think he's wrong. As I said before, it's not local to the current scope, because AutoIt doesn't have that kind of scoping, it's a global variable and calling it something else doesn't make any sense.

[MvGulik]

(Local use at code root level)

Aha. Got it.

​

(other sub-topic)

"globals are bad" -> http://en.wikipedia.org/wiki/Global_variable (header section) seems to contain some good general "why" 's to me.

Edited February 17, 2013 by MvGulik

[MvGulik]

In this instance I think he's wrong. As I said before, it's not local to the current scope, because AutoIt doesn't have that kind of scoping, it's a global variable and calling it something else doesn't make any sense.

Valik argument was not targeted, or limited, to the actual behavior of AutoIt. But at coding practice/logic in general. Edited February 17, 2013 by MvGulik

[czardas]

I don't think Valik's wrong. Perhaps I sometimes misinterpret his words. I see the example as not needing to be declared Global, so I also see where he's coming from here. How to explain the difference between these keywords without confusing people is another matter.

Edited February 17, 2013 by czardas

[AZJIO]

The use of local variables in the global scope only confuses

[MvGulik]

GLOCAL ?

[guinness]

I read Valik's comment (which was from October 2011), went OK I understand and just continued from there. People can continue to use Global even if the variable isn't used within functions, but the thread is dedicated to good coding practice. I only created this to document what is good, not what people should do otherwise there scripts will break.

[czardas]

Indeed. I say it's bad practice to use locals in the global scope because it contradicts Valik's words in the thread linked to. In other words: it's bad practice to declare a local variable outside a function. The variable does not belong in the global scope. It simply shouldn't be their at all.

Global should only be used if a variable truly needs to be Global

Ie use local variables wherever possible instead. Don't declare variables in the wrong scope to begin with. NOTE: he does not mention what keyword is used to declare global variables in this sentence. It is irrelevant how you declare them anyway. They will always take the local scope, regardless of how you declare them - in this case available to the whole script. That's how AutoIt works.

Edited February 17, 2013 by czardas

[AZJIO]

You will be compelled to answer each time to the beginner why you use local variables

Edited February 17, 2013 by AZJIO

[guinness]

Maybe this is easier. If you use variable that isn't in a function and isn't used in other functions, wrap it in a function and declare it as Local.