About variables have per-iteration scope instead of per-loop scope

[Victor Giordano]

Hi gophers! How you doing?

In my work we recently discuss with a buddy about this article. I need to talk about this....

I appreaciate that golang makes a lot of effort on this. Working with clousures cames with perils and the go vet tool emiting a warning is a great thing.

Althought I do not think that chaning language semantics is something 100% good,  see my point: As long I use several languages for making a system this "scope rule" will mismatch with other languajes, for example, javascript.

So from now onwards I shall be aware that for loops have variables scopes in one fashion in Golang and in other fashion in another languages... so at the end of the day, I feel like is adding some burden. If for development we can use a single and sole language (Sauron don't read this :P !) I would think this change is good, but that is not the case in now-a-days. I try to think that with time, perhaps other languages evolves it this way... but.. ¿what if I wanna have my "for loop" with legacy scope (block scope, not per iteration scope)? 

So... I expect to the readers to talk with me, showing what they see and feel. Is not my intention to generate hard feelings at all. I'm a person that work crafting system in group with others.. I have had terrible nightmares working with Scala where implicits and invoking methods as they were feilds were terrible ideas for working in group (perhaps not if you work solo). And this feature recalls me those feelings.

Greetings

Víctor.

[Axel Wagner]

This has come up during the discussion already. I don't know enough about other languages to speak with confidence, but apparently there already is precedent for this and/or some languages are at least considering making a similar change.

Note that scoping rules already vary between languages - in some cases, pretty widely. For example, Python is not block scoped - this works:

def f():

    if True:

        x = 42

    print(x)

And Perl has dynamic scoping, where variables can be scoped to a call stack, instead of any lexical element of the source code. Javascript, as far as I know, is pretty notorious for having extremely idiosyncratic scoping rules (e.g. it is a common confusion how `this` is scoped in different contexts) and also has several different kinds of declarations with AFAIK slightly different scoping rules.

In C, a symbol is only scoped to a single file (as far as the processor is concerned) and in there, only from its declaration onwards, while in Go, a package-scoped definition can appear in any file of any package. And speaking of C, it doesn't have closures at all, so the scoping rules of loop variables are *already* very different.

So I think the case that you *currently* don't have to be aware of how a language is using scoping is pretty vastly overstated. What's more, the majority of programs won't actually be affected by this - and for those that are, it seems that empirically, the new rules will align more closely with what people expect subconsciously.

I don't think you should worry too much. Run your tests with the new loop variable semantics in Go 1.21 to see if everything still works. Most likely, it will - or you will discover a bug in your current code.

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[Victor Giordano]

Thanks Alex, your insight was very helpful.

Allow me to share the feeling I have => I still struggle a little in my mind... I craft web fronts in javascript, and back in golang (and scala or java). With this change I will have two different scoping rules... and I feel I don't need it (because I learn how to use it well) nor ask for them... but it is okay.. changes work that way. The bottom line is: I was already comfortable with the language scope rules.

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V

[Axel Wagner]

So, how often do you depend on this particular scoping behavior, in Go or JS? Do you have any example of where you intentionally rely on the current behavior, that might break with the new one?

I think it's important to emphasize that we do not know of a single case where the current behavior was usefully taken advantage of. Even strong opponents of the change failed to produce any - they just created synthetic (and extremely obfuscated) cases that would change behavior, without any reference to real code these cases where taken from.

You keep asserting that you have to remember different sets of rules - I just don't think that's true, in any real sense. I think you'll find that in reality, it will have literally no effect on you - except that it is not unlikely to fix a bug or two in your existing code base. Because it turns out that no one actually thinks at that level about scoping.

[TheDiveO]

Switching between human languages, such as for me, German and English, required me to learn English at a level that I think in it. Even with their shared ancestry, I don't expect these languages to use the same structure and concepts, like loop variable scoping. Admittedly, Go doesn't allow me to switch in and out into a different language mid sentence, which in human languages sometimes causes quite some hilarious reactions with my colleagues.

[Victor Giordano]

Alex, your second reply was even more powerful in terms of feelings and ideas to work with in order to embrace the change. Probably I'm struggling with an unexpected change... and let's see with time how it goes.

DiveO, thanks you very mucho for your insight... I see your point. For me... the matter would be like ¿ what happens if a given language you know well suddenly changes the rules for implicit or tacit subject? Where the subject would be the variable and the rules for implicit or tacit subject would be the scope. People may wonder. Again... I guess time will answer us all.

Greetings

[TheDiveO]

actually, language changes happen all the time. In German, there is quite some "misuse" esp. by journos that change or follow change in German, not necessarily improving clearness. In Go, so far changes were for the better and I'm glad to change my learning if it benefits the mass of my fellow developers.  

[Victor Giordano]

>  In Go, so far changes were for the better and I'm glad to change my learning if it benefits the mass of my fellow developers.  

Maybe. Let's see how times handle it.

TD;DR;

I praise for changes but it is not easy..  I mean, look at our society (the final reflection of us as an unique aggregated being)... there is room for improvement. We want a better place, we want changes... but ¿do I wanna change? This is a very complex affair to discuss with mate 🧉  and facturas 🥐. 

Dog and cats  allowed too of course

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V