[Haskell-cafe] Space questions about intern and sets
gracjan at acchsh.com
Fri Jun 3 04:53:53 EDT 2005
Scott Turner wrote:
> On 2005 June 02 Thursday 04:38, Gracjan Polak wrote:
>> >>iorefset :: Ord a => IORef(Map.Map a a)
>> >>iorefset = unsafePerformIO $ do
>> >> newIORef $ Map.empty
>>I could have as many dictionaries as there are types. The problem is I
>>get one dictionary for each object which defeats the idea.
> To avoid unsafe operations and get control over the dictionaries that
> created, I would put the desired dictionaries into a state monad.
> of 'intern' becomes
> Ord a => a -> DictionaryState a
> All the code that uses 'intern' would need some modification to deal
> directly with the dictionary state. It may be more complex, but it's
> more solid.
As intern behaves like id and does not have any side effects, I thought
its interface should be purely functional. But I do not see any way to
do it :( I'll end up with a monad, probably.
In related question: does anybody here have experience/benchmarks/tests
how/if is PackedString better (uses less memory) than String in parsing
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