[Haskell-cafe] Parse text difficulty
ctm at cs.nott.ac.uk
Thu Dec 9 20:04:03 EST 2004
Tomasz Zielonka wrote:
> On Thu, Dec 09, 2004 at 05:55:09PM +0000, Conor McBride wrote:
>>Funny you should choose that word:
>>saves me banging the same old drum.
> Is ap alias <# alias <%> for  really the same as zwApply? Probably
> I am missing something.
Yes and no. Depends which list monad you're using. zwApply is the <%>
of one of the list idioms: it corresponds to the 'vectorizing' list monad
whose return is repeat and whose join computes the diagonal of a matrix.
But you're right: library ap for the 'list of successes' monad and zwApply
do not coincide. I tend to use different list functors, depending on what
they're for, so that all the plumbing is correctly cued from the types.
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