On page 39 you say A type can have Ord instance only when it has Eq instance, since if you
want to compare items, you need a way to test if they are equal.
So from my reading of this you are saying that an Eq instance for a type
needs to be supplied before we are allowed to implement compare. However
it is easy to write a compare function that makes no use of the underlying
(==) function. Indeed, once you have done this you can turn around and
write a == b = compare a b == EQ. So I was wondering if you could clarify
the role of constraints in the class declaration.
On Sun, Jul 28, 2019 at 2:38 AM Cosmia Fu
Hi everyone,
Though some of you might already knows, I'm pleased to announce a new Haskell book, *To Kata Haskellen Evangelion*. Link: https://cosmius.bitbucket.io/tkhe/ I believe that it does not have to be hard to learn Haskell.
I begun to write the book in 2017 December, and... to be honest, I don't know what to write now, though I still think it incomplete. It will probably not be updated for quite a while. So I decide to announce it earlier.
I am not a native English speaker, so it might be not fluent or even with a lot of grammar mistakes. It would be very nice of you if you can tell me the mistakes in it, factual, technical or grammar. And also feel free to tell me if you want to read some topic in it.
Thank you
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Cosmia Fu _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.