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Comment by sharmi | Hacker News Reader

I love the simple and clean syntax of Nim. The first time I was very impressed with vim was when I used a wikipedia xml dump parser. What would have literally taken days to complete in Python (atleast on my machine, and god forbid if it had crashed somewhere in the middle) was done in a few mins by nim (again on the same machine). I was blown away!

The one thing that concerns me a bit is that identifiers are partial case-insensitive right?

(That means only the first letters are compared in a case sensitive manner. Other letters are compared case insensitively and underscores are ignored.)

Does it hinder when you need to do refactoring?

Also, I work in vim, and grep for stuff when I need. I am not sure if autosuggests and locating definitions/usage for variables would work. I am sure I must be wrong as I believe the core developers would have thought about it :) I just would like to know how

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Identifiers are "style-insensitive", so case changes and single underscore insertions don't actually change the identifier. There is exhaustive tooling such as nimgrep and ide support built into the compiler (such as find symbol at point equivalents) for helping when a convention is different. It is a strong philosophical position, but it does allow style consistency across a code base even when dealing with foreign symbols.

Wouldn't it have been better to just enforce one style over all nim code?

Seconded. Being able to insert an underscore and have the code still compile sounds like a strange design choice to me. dom96, could you write more on this?

A lot of people have this reaction, but I am still yet to find a single person that gave Nim a proper try only to decide that it is not for them because of style insensitivity.

It's definitely weird and I personally could take it or leave it. But don't let it dissuade you from trying the language.

The idea behind this feature is to let you choose which style you want to write code in.

This sounds like Python's significant whitespace: weird, off-putting for newcomers, but not actually a problem in practice.

yeah! That's exactly how I think of it.

Significant whitespace has some real benefits (enforcing proper indentation, no lines wasted for "}" or "end", etc) too.

Case insensitive and _ ignoring identifiers not so much -- they just add mental burden, encourage different styles in the same codebase, make things ungreppable without special tools, etc. And for what?

If the best one can say about a feature is "people still like the language despite it", it might be better to axe it.

Significant indentation comes with trade-offs -- real benefits, and real detriments. I agree it's entirely understandable that a language designer would include significant indentation, such as Python's use of the off-side rule (even though I don't like it in Python).

Labels (e.g. variable names) coming with style insensitivity is indeed weird, and likely to be far more off-putting for many than significant indentation, though both put together will likely have even more of a negative effect on adoption, in my estimation.

I can imagine benefits to the style insensitivity, but I think those benefits could be had without a style insensitivity, and they come with trade-offs as well when you use style insensitivity to get those benefits (for instance, some typos could be ignored altogether by the parser, but cause the human eye to miss them or cause codebase searches to fail to find all instances of a label when using tools external to the language's implementation itself).

I think some of the benefits of style insensitivity are worthwhile, though, and should be pursued (by other means, preferably). For example, a language feature that allows one to define (with a single line of code, perhaps a pragma declaration) a standard for label formatting could be used to make library functions conform to your project's code style standards would be a much more palatable solution to the problem of alien code looking alien than style insensitivity, in my opinion. I think a (Proposed? In development?) feature of Nim -- syntax "skins" -- might offer exactly that, and it could result in effectively being able to turn off style insensitivity in your projects. If so, I would expect that to become the standard way to handle code style in Nim projects.

A code formatter/linter (similar to gofmt) would do the trick and prevent ambiguity.

> encourage different styles in the same codebase

Actually, case sensitive identifiers encourage this. If a library uses camelCase but your code base uses snake_case then you will be using a mix of camelCase and snake_case in order to use that library.

That is a real benefit and is entirely the point of this feature.

This. I can't count the number of times I've used two libraries with different casing just to have my own code end up as a mess of both..

I can see the point though that grepping, and things like editors which highlight the selected variable would have to take these rules into consideration. It's a valid concern but I feel the benefit of clean unified code is more important.

>This. I can't count the number of times I've used two libraries with different casing just to have my own code end up as a mess of both..

Whereas referencing the exported identifiers from the library with a different style than they are written with in the library's code sounds more satisfactory to you?

Yes, that way my code looks more like one entity than a mess of different things.

I can see why you are skeptical of it but once you've used it for a while it becomes second nature. And you can always mix if you want to. The thing is that you can choose how you want to do it. And there are extremely few cases where the casing actually makes the identifiers different (keeping it mind that the first character is type sensitive).

>Actually, case sensitive identifiers encourage this. If a library uses camelCase but your code base uses snake_case then you will be using a mix of camelCase and snake_case in order to use that library.

Which will be totally fine, as it involves different variables / things pointed at.

Whereas the "case/underscore insensitive" qualifiers lets you have 10 different versions of the same variable name, in the same codebase -- even without using any third party "library".

Besides, the problem of "third party library uses a different style" is easily solved by having a tool like go fmt that enforces a unique single style. End of story.

Python's significant indentation is also off-putting for a lot of people who are no longer newcomers to the language. I think some people are also unhappy with its effects without realizing that the significant indentation is contributing to those effects, such as how significant indentation interacts with other language features to force trade-offs between some programming techniques and longer lines of code.

Code I write for work these days (not including Puppet config, which is Ruby, or shell scripts) is all Python, and I still dislike the significant indentation. I do not dislike significant indentation per se, but I do dislike some of its effects in concert with other language design decisions. I did have a knee-jerk negative reaction to Python's significant indentation by itself when I first encountered the language a long time ago, but I got over it when exposed more to a couple other languages with significant indentation where it felt less off-putting. For instance, I never had a problem with Haskell's use of the off-side rule for specific block types (though I'm far less familiar with Haskell in general than Python), and did not even realize the language used the off-side rule for a while because it blended so seamlessly and naturally with the "obvious" way to organize code in every case where the rule applies. To repeat and clarify my feeling on the matter, though, I still dislike the off-side rule in Python, because of its interactions with other language features.

I don't want to distract from Nim discussion to create a whole separate debate, so I may not respond to further questions on the subject here -- I just wanted to point out that significant indentation is not devoid of its trade-offs for the benefits some people enjoy. I understand that some people like significant indentation so much that the other concerns that arise might end up beneath their notice, and others may hate it just out of some stubborn attachment to the conventions of other languages, but it is worth noting that it really does come with trade-offs, and there are also many people who dislike it specifically for the effects those trade-offs have on their code, and that this is a perfectly valid and reasonable position to take (even for those who find it difficult to identify or articulate the specific, undesirable causes of those effects they dislike). There are problems in practice, but not problems so big that one cannot reasonably ignore them if one likes the positive effects of significant indentation.

My usual solution to the problems Python's significant indentation solves would just be to fire people who lack such attention to detail that they cannot learn to format code nicely, though. As such, the language enforcing it offers less benefit for me than it might for others.

> My usual solution to the problems Python's significant indentation solves would just be to fire people who lack such attention to detail that they cannot learn to format code nicely, though.

While I might not go as far as you here (firing), I think your underlying point about attention to detail is entirely correct and generally doesn't get the attention it deserves.

Lack of attention to detail re code style issues is probably an early (i.e. obvious) indicator for lack of attention to detail in other more important areas.

(Note: I say indicator, because it's entirely possible the developer just doesn't care about code style, or has a different preference, yet still has attention to detail for other more important areas)

Would it have made sense to have a way to specify a particular style per project, that would then be enforced by the compiler?

> I am still yet to find a single person that gave Nim a proper try only to decide that it is not for them because of style insensitivity.

Unfortunately, it's unlikely that you can collect any meaningful data on how many people refuse to try it altogether (or put enough time into it for anyone in the Nim community to hear about it) because of style insensitivity.

Perhaps, but I bet that would dissuade a very large proportion of people from trying the language.

Compared to the horror of case insensitive identifiers?

A bit hyperbolic, there are loads of languages that are case insensitive.

Are you really only using case to distinguish different variables? That seems more error prone.

The "style insensitivity" decision dissuades me much more strongly than some case sensitivity style enforcement in the language would.

It seems odd to me that Nim developers chose to go with that "style insensitivity" (which I would have predicted would be highly controversial and very discouraging for many, many developers) but indentation sensitivity (which is less controversial, but still more controversial than indentation insensitivity; shockingly large numbers of people dislike it, including me at least when combined with some other language features).

If the goal was widest possible appeal and adoption, those two decisions should have been swapped, I think. If the goal is related to some specific philosophical stance, however, I suppose every language developer who doesn't just want to recreate PHP or VisualBasic needs to pick the hill on which he or she is willing to die, and only time will tell whether it will be worth it.

The goal of any language designer is not to appeal to the widest possible group of people but to create a language that appeals to them. In this case style insensitivity is something that Araq wanted in his language and so he implemented it.

>It is a strong philosophical position, but it does allow style consistency across a code base even when dealing with foreign symbols.

Every language seems to have a bizarro decision that kind of breaks it for many people. This is Nim's. It could be worse, it could be "Who need's Generics? They're costly anyway", like Go's...

IMHO if such a superficial aspect is what's breaking it for someone, I'm thinking they're a bit hung up on trivia, the rest of Nim is really very good and other languages should copy it more. In practice the symbol thing really isn't an issue...

I write my Nim code in Vim. I've never had any problems with auto-suggests.

My Vim config for Nim can be found here: https://github.com/jboy/dotfiles/tree/master/vim (based upon https://github.com/zah/nim.vim , with a few improvements to my taste).

In particular, Vim syntax highlighting for Nim: https://github.com/jboy/dotfiles/blob/master/vim/syntax/nim.... and some convenient Vim mappings to jump around in Nim: https://github.com/jboy/dotfiles/tree/master/vim/ftplugin/ni...

I also use (and recommend) the CamelCaseMode Vim plugin with Python & Nim.

> Does it hinder when you need to do refactoring?

It has almost never been an issue for me and I don't use any case-insensitive refactoring tool. Just write variables in a consistent style and let completion help you stay consistent.

Because Nim has an excellent 'compiler service', the symbols can be identified at the AST level instead of the textual level. In practice, most code bases stick to some conventions, and the possible ambiguity is rarely an issue, in my experience

Is there a style guideline for nim like pep8?

There is! NEP-1 is what you're looking for: https://nim-lang.org/docs/nep1.html

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