[Haskell-beginners] Usage of $

[Mike Meyer]

Are you saying that GHC doesn't have a haskell parser?

On Mon, Jun 8, 2015 at 12:06 PM, Rein Henrichs <rein.henrichs at gmail.com>
wrote:

> The point is that there is no parsing happening here. Just evaluation.
>
> On Mon, Jun 8, 2015 at 3:20 AM Mike Meyer <mwm at mired.org> wrote:
>
>>
>> On Jun 8, 2015 05:01, "Martin Vlk" <martin at vlkk.cz> wrote:
>> >
>> > Mike Meyer:
>> > > s mp $ n - 1 parses as s mp (n - 1)
>> > > s mp n - 1 parses as (s mp n) - 1
>> >
>> >
>> > Hi, I think it is misleading to say that $ "parses" to something.
>>
>> Which is why I didn't say such a thing. The two sentences show how the
>> expressions he was having trouble with are parsed.
>>
>> > ($) is an infix operator with type:
>> >
>> > ($) :: (a -> b) -> a -> b       -- Defined in ‘GHC.Base’
>> > infixr 0 $
>> >
>> > So what it does is it takes a function on the left hand side and applies
>> > it to the second argument on the right hand side. The trick is it has
>> > the lowest possible precedence value (0) so everything on the right hand
>> > side will be evaluated before applying the function on the left.
>>
>> Which explains why the expression containing a $ parses as it does, which
>> is also useful information.
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>
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