Proposal: NoImplicitPreludeImport

Tillmann Rendel rendel at
Wed May 29 12:12:56 CEST 2013


Ian Lynagh wrote:
> I have made a wiki page describing a new proposal,
> NoImplicitPreludeImport, which I intend to propose for Haskell 2014:

I like the idea of having an ImplicitPreludeImport extensions that can 
be switched on and off. I'm not sure it should be switched off by default.

For Haskell beginners, I think it is most convenient if they can write 
some interesting programs without any imports. This enables learning 
some Haskell without learning about modules and imports at all. So I 
think that beginners want an implicit import of (some) Prelude.

(Maybe it would be good if tutorials or lecture notes could specify in a 
very easy way what Prelude to use exactly. A bit like #lang lines in 

Advanced Haskell programmers have long import lists and often long 
extension lists in their modules anyway, so the additional "import 
Prelude ()" or "{-# LANGUAGE NoImplicitPrelude #-}" shouldn't hurt them 
so much. Except that currently, "import Prelude ()" doesn't actually 
work in practice, because not all Prelude exports are available from 
other modules. I think this should be fixed independently of this proposal.


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