-------- Original Message --------
Subject: Re: [Haskell-cafe] Word rigid in "`a' is a rigid type variable..."
From: Brandon Allbery <allbery.b@gmail.com>
To: Vlatko Bašić <vlatko.basic@gmail.com>
Cc: Haskell-Cafe <haskell-cafe@haskell.org>
Date: 13.11.2013 18:42
On Wed, Nov 13, 2013 at 12:24 PM, Vlatko Basic <vlatko.basic@gmail.com> wrote:--
Thanks for explanation. If I understood correctly, 'rigid' refers the requirement, not the type itself.
I think that more intuitive/understandable would be something like
'b' has too rigid type for 'a' ...
Not really, unless you're talking about some notion of "types of types" (which exists, but not in this way). You're still trying to hold onto some notion that `a` is flexible; but the compiler does not care about the kind of flexibility you want. You will need to let go of that "flexible" for Haskell's type system to make sense.
(This will make more sense when you start using typeclasses. Or, at least once you've tried to use your notion of "flexible" with them, because it will lead you straight into a brick wall that is not flexible at all.)
brandon s allbery kf8nh sine nomine associatesunix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net