[erlang-questions] literal character syntax

[Björn-Egil Dahlberg]

On 2014-05-14 16:15, Fred Hebert wrote:
> I think the argument here is specifically about whitespace characters.
>
> For example, using:
>
> starts_with([$  | _]) -> space;
> starts_with([$	 | _]) -> tab;
> starts_with([$
>   |_]) -> newline.
>
> Is currently allowed, but it is arguably clearer to use:
>
> starts_with([$\s | _]) -> space;
> starts_with([$\t | _]) -> tab.
> starts_with([$\n | _]) -> newline.
>
> Vlad here recommends deprecating the former case, while recommending the
> latter form.
>
> I would tend to agree for the sake of readability, but would like a
> regular deprecation cycle with warnings explaining the recommended
> changes ("The $<space> form is being deprecated, replace with $\s" or
> something).
I like this proposal.

I don't know how fast we could remove $ , $    , etc (earliest 19?) but 
we could certainly emit irritating deprecation warnings that make people 
want to fix their code.

// Björn-Egil


>
> Regards,
> Fred.
>
> On 05/14, Sean Cribbs wrote:
>> They are incredibly useful in pattern-matching simple string arguments. e.g.
>>
>> case erlang:system_info(version) of
>>      [$5, $., $1, $0 | _ ] -> ok;
>>      _ -> fail
>> end
>>
>>
>> On Wed, May 14, 2014 at 4:28 AM, Vlad Dumitrescu <vladdu55@REDACTED> wrote:
>>
>>> Hi!
>>>
>>> I would like to make a suggestion regarding the accepted literal
>>> characters syntax. At the moment, any character following a $ is accepted
>>> as itself. I find it very confusing when these characters are whitespace or
>>> control chars and my suggestion is to refuse these literals. Most of them
>>> have escaped representations and the others should be written as integers
>>> anyway.
>>>
>>> What do you think? Is anyone using these in a meaningful way?
>>>
>>> best regards,
>>> Vlad
>>>
>>>
>>> _______________________________________________
>>> erlang-questions mailing list
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>>>
>>>
>>
>> -- 
>> Sean Cribbs <sean@REDACTED>
>> Software Engineer
>> Basho Technologies, Inc.
>> http://basho.com/
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