[Haskell-beginners] A very counterintuitive behaviour of Haskell

[Magnus Therning]

On Thu, Jan 27, 2011 at 15:02, Magnus Therning <magnus at therning.org> wrote:
> On Thu, Jan 27, 2011 at 14:55, Renzo Orsini <renzo.orsini at gmail.com> wrote:
>> In studying Haskell, I produced the following output from GHC:
>>
>> xxx-3:~ xxx$ GHCi
>> GHCi, version 6.12.3: http://www.haskell.org/ghc/  :? for help
>> Loading package ghc-prim ... linking ... done.
>> Loading package integer-gmp ... linking ... done.
>> Loading package base ... linking ... done.
>> Loading package ffi-1.0 ... linking ... done.
>> Prelude> let f 7 = "ok"
>> Prelude> let f x = "no"
>> Prelude> f 3
>> "no"
>> Prelude> f 7
>> "no"
>>
>> I suppose it is correct. However, for someone who is interested in the language, it seems very counterintuitive... Somebody would be so kind to explain to a neophyte this "feature" of the language?
>
> I suppose it comes down to pattern matching being on form, not on value.

What an amazingly wrong answer by me, sorry for the noise ;-)

/M

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Magnus Therning                      OpenPGP: 0xAB4DFBA4
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