[web-devel] Database connection laziness (yesod)
jedahu at gmail.com
Wed May 18 00:32:06 CEST 2011
Another lazy question:
> fun :: Int -> Int
> foo a = runReader ask (fun a)
> bar a = runReader (return 3) (fun a)
foo causes (fun a) to be evaluated but bar doesn't. Is the same true
for database connections? Are they created lazily?
I ask because it would be neat to be able to write:
> runDB $ getFromCache cache key
where getFromCache queries the DB only on a cache miss, and have a
connection created only in the case of a cache miss.
I have tried test this myself, but I can't get ghci to cooperate and
load yesod from source.
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