[Haskell-cafe] ANNOUNCE: pipes-core 0.0.1
blamario at acanac.net
Sun Mar 11 18:22:37 CET 2012
On 12-03-11 12:39 PM, Chris Smith wrote:
> On Sun, Mar 11, 2012 at 10:30 AM, Mario Blažević<blamario at acanac.net> wrote:
>> (p1>> unawait x)>>> p2 = (p1>>> p2)<* unawait x -- this one
>> tripped me up
> I don't think this could reasonably hold. For example, you'd expect
> that for any p, idP>> p == idP since idP never terminates at all.
> But then let p1 == idP, and you get something silly. The issue is
> with early termination: if p2 terminates first in the left hand side,
> you don't want the unawait to occur.
No, idP does terminate once it consumes its input. Your idP >> p
first reproduces the complete input, and then runs p with empty input.
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