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

[Eric Seidel]

Yes, the inference of call-stacks is being removed. I'm just waiting for
the patch to be reviewed. 

On Mon, Mar 28, 2016, at 06:22, George Colpitts wrote:
> Was there any consensus on how to move forward on this? I just found
> another example of
> ​​
> 8.0 type which is not beginner friendly:
> 
> bash-3.2$ ghci
> GHCi, version 8.0.0.20160204: http://www.haskell.org/ghc/  :? for help
> Prelude> True
> True
> it :: Bool
> Prelude> True || undefined
> True
> *it :: ?callStack::GHC.Stack.Types.CallStack => Bool*
> 
> 
> 
> On Wed, Mar 2, 2016 at 1:56 PM Ericson, John <john_ericson at brown.edu>
> wrote:
> 
> > 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.
> >
> > John
> >
> >
> > On Wed, Feb 24, 2016 at 6:07 PM, Manuel M T Chakravarty <
> > chak at justtesting.org> 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 —to avoid overloading— that are no longer valid in the full Prelude.)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 seidel.io>:
> >> >
> >> > 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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> >>
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