[erlang-questions] questions about dict

Dustin Sallings <>
Tue Aug 21 09:12:28 CEST 2007


On Aug 20, 2007, at 23:09, Bjorn Gustavsson wrote:

>> 	1)  There doesn't seem to be a way to get the length of a dict
>> directly, although it seems to be directly stored (I'm using fold
>> right now to calculate it).
>
> Use orddict:size/1.
>
> It seems to be undocumented for no good reason. We will update the
> documentation in R12B.

	Ah, I see this exists in dict as well.  Thanks.  It seemed to be an  
obvious missing thing.

>> 	2)  I can't seem to make a guard for a dict because the record
>> format is unavailable to me at compile time (I'm working around this
>> by matching tuple and hard-coding a tuple pattern for identifying a
>> dict).
>
> That is intentional (and even mentioned in the documentation).
>
> There is no portable way to test for a dict in a guard.

	Where is this documented?  I looked around for a while and couldn't  
find anything either way.  There's clearly a gap in my understanding  
of guards, records, or dicts.

-- 
Dustin Sallings





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