Top Level TWI's again was Re: [Haskell] Re: Parameterized Show
k.schupke at imperial.ac.uk
Tue Nov 23 08:52:56 EST 2004
Okay - but then you can keep state in haskell by using a driver thread
and channels like in the example I posted. I guess I should have said
it is best practice to check the real state rather than a (possibly wrong)
Benjamin Franksen wrote:
>On Tuesday 23 November 2004 10:39, Keean Schupke wrote:
>>Adrian Hey wrote:
>>>This is one situation, but certainly not the only possible one. You have
>>>the same problem with interfacing to any unique stateful resource (or
>>>even if you have a multiple but finite supply of these resources).
>>No you don't... Most devices have registers, those registers contain
>>values, you can inspect those values to see if the device has been
>>initialised. You can then write a guard on the initialisation that really
>>checks if the device has (or hasn't) been initialised rather than rely
>>'shadow' copies in RAM.
>Alas, unfortunately not every device is designed in this way (I can give
>examples if you want). Adrian is right in that there is not only badly
>designed C libraries but also badly designed hardware!
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