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

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 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@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the case with, e.g., a Prelude omitting type classes as you need to introduce new names —to avoid overloading— that are no longer valid in the full Prelude.)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 :

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 _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

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