[erlang-questions] -spec tuple variable size

Dmitry Kolesnikov <>
Thu Nov 29 16:41:54 CET 2012


Hello,

No this do not work!
here is my snippet

-- CLIP --
-type entity()    :: tuple(integer()).

-spec create(atom(), entity()) -> ok.
create(abc, {1, 1})

test.erl:237: The call test:create('abc',{1,1}) will never return since the success typing is (any(),{integer()}) -> 'ok'

-- CLIP --

- Dmitry


On Nov 29, 2012, at 6:05 AM, Slava Yurin <> wrote:

> Hi, Dmitry.
>  
> May be "tuple(Type)" help you?
>  
> -type my_tuple() :: tuple(integer()). % {1}, {1,1}, {1, ...} 
>  
> 29.11.2012, 05:10, "Dmitry Kolesnikov" <>:
>> Hello,
>> 
>> Thanks for response!
>> Let me explain better what I am trying to achieve.
>> "The shorthand [T,...] stands for the set of non-empty proper lists whose elements are of type T." 
>> I am looking for similar definition but for tuples.
>> 
>> My application serialises tuples into disk. The size of tuple is unbound but tuple elements a fixed to string, binary, number, boolean or undefined. I cannot use " "|" operator to define as many variants as you like" because number of variants is unlimited. Well practically, I do have a hard limit of 4096 elements per tuple but I am lazy to type in 4096 variants :-) 
>> 
>> - Dmitry
>> 
>> On Nov 28, 2012, at 11:50 PM, Motiejus Jakštys <> wrote:
>> 
>>  On Wed, Nov 28, 2012 at 9:10 PM, Dmitry Kolesnikov
>>  <> wrote:
>>  but compiler fails syntax error before: ','
>> 
>>  -- CLIP --
>>  -type value()     :: string() | binary() | number() | boolean() | undefined.
>>  -type entity()    :: [{atom(), value()}] | {field()}.
>>  These should be fine.
>>  -type field()      :: value() | value(), field().
>>  Maybe you meant
>>  -type field() :: value() | {value(), field()}.
>> 
>>  ?
>> 
>>  In general, if you want to define tuples of different sizes in -spec,
>>  you use the "|" operator to define as many variants as you like.
>> 
>>  Likely I don't understand what you are trying to define.
>> 
>>  -- 
>>  Motiejus Jakštys
>> _______________________________________________
>> erlang-questions mailing list
>> 
>> http://erlang.org/mailman/listinfo/erlang-questions
>> 

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