[erlang-questions] Request feedback on example project

Lloyd R. Prentice <>
Thu Feb 4 16:36:09 CET 2016


> On second thought, I think the extra newlines actually improve *reading*
> but may somewhat impare *scanning*.

> Consider:
> https://github.com/zxq9/zuuid/blob/master/src/zuuid.erl

Ah, much easier on my aging eyes.

Best wishes,

LRP

Sent from my iPad

> On Feb 4, 2016, at 7:52 AM, zxq9 <> wrote:
> 
> On 2016年2月4日 木曜日 07:29:06 Nathaniel Waisbrot wrote:
>>> 
>>> I don't even like the idea of using maps for this, but the "old
>>> fashioned" tuple type seems to be discouraged in the R18 docs. Meh.
>>> 
>>> So much for trying to be hip to the new thing. I like my old tuples.
>>> I don't think there is anything in here that doesn't work even with
>>> rather old ERTS releases, so I'm switching this (back) to tuples.
>>> With regard to tuples VS maps for trivial things like this... I almost
>>> feel like its a case of getting a newfangled toy and simply feeling
>>> compelled to use it everywhere.
>> 
>> As someone with less than 10,000 hours of OTP code under my belt, I found
>> this change (tuples to maps) to be so useful that I immediately upgraded
>> all my code to require version 18.
>> With the tuples, I had to check the documentation every single time I made
>> a supervisor to confirm whether it was `intensity` or `period` first. I
>> also would get copy/paste errors because I'd copy the child spec for a
>> worker that was set to `brutal_kill` and use that as template for a
>> supervisor without changing it to `infinity`.
>> The new maps are self-documenting and they provide sane defaults so that if
>> I want a vanilla supervisor I can just say `#{id => cool_super, start =>
>> {M, F, A}, type => supervisor}`.  Not only do I avoid dumb bugs, but it's
>> also clear that this is a vanilla supervisor and not something more
>> interesting.
>> 
>> It seems like a small change, but I thought the old tuples were _awful_ and
>> I was very happy to see them marked as deprecated.
> 
> Having a method for defaulting to sane values (using maps for convenience)
> makes perfect sense. But *deprecating* tuples bothers me -- it means that
> eventually every piece of OTP code is going to break or have to be
> (arbitrarily) moved forward to maps for no gain.
> 
> Ideally, if I could have my way... and actually I can, so I'm going to add
> something like this to my own templating tool...
> 
>  vanilla_worker(Name) ->
>      vanilla_worker(Name, []).
> 
>  vanilla_worker(Name, Args) ->
>      {Name,
>       {Name, start_link, Args},
>       permanent,
>       brutal_kill,
>       worker,
>       [Name]}.
> 
> ...And maybe one or two more really common ones.
> 
> I find it every bit as annoying to define a bunch of nearly identical
> maps as a bunch of nearly identical tuples. I generally only have to do
> this from scratch *once* per project, which is really not a big deal.
> Its annoying either way, but its typically a one-off annoyance.
> 
> (Until now I've just had a template I have a script pull over and start
> from there, so I sort of forgot that this could be annoying.)
> 
>>> Oh, a layout issue.  I don't like big black blobs (except when I
>>>> write them).  So
>>>> %% wdrwertwertwert
>>>> %% wertwertwertwrt
>>>> %% wretertwertwertew
>>>> -spec frgsdfgdfghsdfg
>>>> asdfasdf(sdfgsdfg) ->
>>>>    ....
>>>> 
>>>> is just a bit too much for me to be comfortable with.  I'd find
>>>> it easier to read with blank line after the %% comment block
>>>> and a blank line after the -spec.
>>>> 
>>>> I find that with my OWN code it's so obvious that packing it
>>>> tightly doesn't impair readability, but with someone else's
>>>> code well-placed blank lines never go amiss.  I can only suppose
>>>> that I'm in error about my own code and that it too could do with
>>>> more blank lines.
>>> 
>>> *MY* code is always perfectly readable as big, immaculate, unbroken
>>> blocks. Until a few months later. Ugh.
>>> 
>>> I'm not sure where I stand on the line break issue, really, but since
>>> you mentioned it I'm trying out a line between doc and spec, a line
>>> between spec and definition, and two lines between functions (but no
>>> lines between function clauses -- I already know that confuses me,
>>> especially with un-specced/un-docced functions).
>> 
>> 
>> I don't feel very strongly on this one (I do about the supervisor spec),
>> but I find the tight-packed blocks _more_ readable in other people's code.
>> I run my eyes down the left-hand side and see
>> 
>> %
>> -
>> a
>> 
>> And that's pretty clearly (1) some comments, (2) a compiler directive, (3)
>> a function. They all go together: I expect the comment to be function
>> documentation and the dash to be a function spec.
>> 
>> If I see
>> 
>> %
>> 
>> -
>> 
>> a
>> 
>> Then the comments might be module-level comments and the directive might be
>> an export or an if or a define or a type declaration and I have to read
>> more characters to figure out if those three lines are related.
> 
> I sometimes think so myself. In this case, though, where every function has
> an explicit `%% @doc` at the head of the function docs and everything else
> follows a pretty obvious pattern, I do indeed find it easier with the extra
> lines. With a mishmash of styles in a single source file, though... ugh. I
> think it would get really annoying. Tomorrow I'll check again and see which
> I like. Part of my goal here is to get some feedback before I start doing
> more open-source stuff... the place I've been coding the last year has been
> rather niche and impossible to make generally applicable someplace like
> github.
> 
> On second thought, I think the extra newlines actually improve *reading*
> but may somewhat impare *scanning*.
> 
> Consider:
> https://github.com/zxq9/zuuid/blob/master/src/zuuid.erl
> 
> One clear advantage is that my super-lazy-man's navigation in vi is far
> more precise now, as each function and spec had is the start of what the
> editor sees as its own block. Not a big deal (I usually jump directly to
> wherever I want to go), but it is sort of nice.
> 
> -Craig
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