[erlang-questions] Trouble with init/1 spec
Wed Mar 24 17:19:59 CET 2010
On Mar 24, 2010, at 9:00 AM, Kostis Sagonas wrote:
> The type
> [string() | non_neg_integer()]
> constrains the input argument better than list()
>> Declaring it as list(any()) means the fields on the record have
>> to all be declared any(). As long as my port field is declared
>> non_neg_integer() in the record definition, I can't get past the
>> dialyzer warning.
> Huh? Are you sure? The record fields can be declared whatever
> type you want. I am not sure to what dialyzer warning you are
> referring to, but perhaps we can take this off list.
I didn't state that too clearly. The list(any()) caused dialyzer to
deduce that the record assignment was creating an any() value in a
field, therefore my record declaration each field needs to be any()
rather than string() or non_neg_integer().
If I make the arglist [string() | non_neg_integer()], then I have to
declare all my string() fields in the record to be of the same type
because of the record constructor assignments which is really
misleading to label a server name or user name as a non_neg_integer()
and propagate that to any functions that access the field.
Right now the only way to get around it easily is to make my port
field a string() and do the list_to_integer/1 conversion every time I
access it. That way all the fields in the init/1 list just happen to
This seems to be a general problem for the init/1 behaviour callbacks
which are designed to be flexible, but don't map easily to a record
assignment that dialyzer can reason about.
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