Two things

1: That doesn't solve the issue of sharing constants between modules
2: I use strings because I match it against user supplied input that I do 
not want to convert to atoms

Correct me if im missing something

Mads

On Monday, May 23, 2016 at 5:45:30 PM UTC+2, José Valim wrote:
>
> Why not use atoms? Atoms are precisely that: constants.
>
>
>
> *José Valim*
> www.plataformatec.com.br
> Skype: jv.ptec
> Founder and Director of R&D
>
> On Sun, May 22, 2016 at 12:16 PM, Nytz12 <[email protected] 
> <javascript:>> wrote:
>
>> Hi
>>
>> I use the following pattern to define cross module constants
>>
>> defmodule Visitor do
>>
>>   defmodule FilterTypes do
>>     def c_GREATER_THAN, do: "greater_than"
>>     def c_LESS_THAN,    do: "less_than"
>>     def c_IS,           do: "is"
>>     def c_IS_NOT,       do: "is_not"
>>   end
>>   ...
>>
>> Which lets me do something like this from other modules
>>
>> Visitor.FilterTypes.c_GREATER_THAN # == "greater than"
>>
>> Problem is that I just discored that these 'constants', which are really 
>> function calls, cannot be used to do pattern match like:
>>
>> def filter(query, filter, field, value) do
>>     case filter do
>>       FilterTypes.c_GREATER_THAN -> greater_than(query, field, value)
>>       FilterTypes.c_LESS_THAN    -> less_than(query, field, value)
>>       FilterTypes.c_IS           -> is(query, field, value)
>>       FilterTypes.c_IS_NOT       -> is_not(query, field, value)
>>       _                          -> {:error, "unknown filter", filter}
>>     end
>>   end
>>
>> Is there a better approach i'm missing?
>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "elixir-lang-talk" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to [email protected] <javascript:>.
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/elixir-lang-talk/ace6b869-dfce-4d3f-aeeb-2d9bc4583f03%40googlegroups.com
>>  
>> <https://groups.google.com/d/msgid/elixir-lang-talk/ace6b869-dfce-4d3f-aeeb-2d9bc4583f03%40googlegroups.com?utm_medium=email&utm_source=footer>
>> .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>

-- 
You received this message because you are subscribed to the Google Groups 
"elixir-lang-talk" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/elixir-lang-talk/41c6ba14-9611-4f8b-b43f-bc72ee336b0d%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to