New type of ($) operator in GHC 8.0 is problematic

Ericson, John john_ericson at
Wed Mar 2 17:56:29 UTC 2016

I dispute your second point a bit: I consider any Prelude changes a
standard library change than a language change, not withstanding the fact
the Prelude is imported by default. Any beginner-language library can still
be imported from normal code. Likewise a "hygienic copy paste" would simply
import the beginner prelude qualified and mangle identifiers as necessary.

I'm inclined to think the Racket way is the only true solution here.


On Wed, Feb 24, 2016 at 6:07 PM, Manuel M T Chakravarty <
chak at> wrote:

> Two notable differences between Racket and the situation in Haskell is
> that (1) Racket has a full blown IDE to support the staged languages and
> (2) AFIK any Racket program in a simpler language is still a valid Racket
> program in a more advanced language. (The latter wouldn’t be the case with,
> e.g., a Prelude omitting type classes as you need to introduce new names
> —to avoid overloading— that are no longer valid in the full Prelude.)
> Manuel
> > Eric Seidel <eric at>:
> >
> > On Wed, Feb 17, 2016, at 08:09, Christopher Allen wrote:
> >> I have tried a beginner's Prelude with people. I don't have a lot of
> data
> >> because it was clearly a failure early on so I bailed them out into the
> >> usual thing. It's just not worth it and it deprives them of the
> >> preparedness to go write real Haskell code. That's not something I'm
> >> willing to give up just so I can teach _less_.
> >
> > Chris, have you written about your experiences teaching with a
> > beginner's Prelude? I'd be quite interested to read about it, as (1) it
> > seems like a natural thing to do and (2) the Racket folks seem to have
> > had good success with their staged teaching languages.
> >
> > In particular, I'm curious if your experience is in the context of
> > teaching people with no experience programming at all, vs programming
> > experience but no Haskell (or generally FP) experience. The Racket "How
> > to Design Programs" curriculum seems very much geared towards absolute
> > beginners, and that could be a relevant distinction.
> >
> > Thanks!
> > Eric
> > _______________________________________________
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> > ghc-devs at
> >
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