[Haskell] overuse of maybe and [] in prelude and libs

Simon Peyton-Jones simonpj at microsoft.com
Thu Apr 8 18:41:21 EDT 2004

| > Haskell is pretty good about letting you install a different
Prelude, so you could try it yourself.
| Hmm.  That's interesting!  How does this work?

It's very simple. Write your own Prelude as a Haskell module MyPrelude.

Then to use it, say
	module Foo where
	  import Prelude ()
	  import MyPrelude

(GHC lets you omit the 'import Prelude ()' by saying

No, there is no auto-magic; you are simply getting a different library,
that is all. And you have to write that library.

No problem with some modules using MyPrelude and some using Prelude.
(Any more than there's a problem when some modules import module A and
some import module B.)

Actually Haskell doesn't let you redefine *everything*, but GHC does:
read section 7.3.5 of the GHC manual


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