[Haskell-cafe] Splitting off many/some from Alternative

[Brandon Allbery]

On Mon, Dec 12, 2011 at 00:18, Gregory Crosswhite <gcrosswhite at gmail.com>wrote:

> It is only recently that I have been able to grok what some and many are
> even about (I think), and they seem to only make sense in cases where
> executing the Alternative action results in a portion of some input being
> consumed or not consumed.  "some v" means "consume at least one v and
> return the list of items consumed or fail", and "many v" means "consume
> zero or more v and return the list of items consumed or the empty list of
> none are consume".  It thus makes sense for there to be some subclass of
> Alternative called something like "Consumptive" that contains these methods.


"Parsive"?

I think the only reason they're in there is that Applicative and
Alternative "came about" via experimentation with parsing (Applicative
started its pre-ghc life as a parser combinator library).

-- 
brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
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