> > If I use an STRef to a record, will a new record be created
> > each time I want
> > to update a single field? Or can I expect GHC to optimize it
> > and have the field of the record updated in place?
>
> You'll get a new record for each update. This might not be so bad
> though, depending on the number of fields in your record.
One of them has 4, the other 3, but they might grow bigger...
> Here's another trick if you use this route:
<added some parenthesis>
> data E s = E{
> refi :: !(STRef s Int),
> refc :: !(STRef s Char)
> }
>
> and compile with -funbox-strict-fields. This will eliminate the boxing
> of the STRefs.
Nice, thanks :)
One more question.
I'm passing that 'record' around as an implicit value. The record as STRefs
that I use to collect info, but it also has some pure fields with 'read-only'
info. Something like,
data E s = E{
refi :: STRef s Int,
refc :: STRef s Char,
max :: Int
}
In some functions I might need only some pure fields, and none of the STRefs,
but since I pass something of type 'E s' around, everything ends up beeing
monadic. Is using two records (on with STRefs and one with pure fields) the
only/best way to avoid this?
I would like to use two records, doesn't seem natural, but I also don't like
to end up using monadic functions when they are, in fact, pure...
Thanks,
J.A.
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