Re: Burning bridges

Good point - some courses still even use Hugs... Tom El May 22, 2013, a las 9:15 PM, Carter Schonwald escribió:

I don't think so. You could just tell GHC / ghci to do Haskell 2010/98 and have the old base.

This change does not constitute retconning prior base/preludes, but rather a new base / prelude that the community wishes to use going forward. (If I'm wrong, someone please correct me)

Point being, old standards for base / prelude will still exist. Use those if you can't adjust your teaching materials. Granted the students won't be able to use as many libraries immediately in such a course, but that's your choice to make. On 23 May 2013 07:32, Malcolm Wallace wrote:

...

-20 for generalising the Prelude +1 for removals from the Prelude -1 for adding monomorphic stuff +1000 for doing nothing

You are all nuts. :-)

I don't know if I'd go quite _that_ for as Malcolm for the weightings for the different proposals...

But I was speaking with a few other tutors of an introductory CS/programming course that uses Haskell (note: it's teaching programming with Haskell, not teaching Haskell per se: for example, all pattern matchings must be done with case statements as the lecturer considers top-level pattern matching a Haskell-specific quirk) about these proposals...

We have plenty of students who have trouble understanding existing functions and types themselves; if we were to suddenly find map, filter, etc. with generalised type signatures then it would confuse the matter even further (especially as they've only "seen" the standard Eq, Ord and Show classes, and even then only in deriving statements and type signatures to be able to use ==, /=, etc. rather than knowing how to write an instance of them themselves).

(Admittedly, they only see these list functions in roughly the last third of the course; even so, despite having just written their own map, filter, etc. functions first for Strings and then generalising them to work on any list in a tutorial a few weeks back, when it came time to work on their assignment when map and filter would come in handy some still kept writing the list traversals by hand due to unfamiliarity of these functions when compared to all the manual list traversal they'd already done.)

If the types in the Prelude were generalised, it might be possible to have a custom Prelude used for the course; however, for this to be used we'd either have to:

a) get them to use rote boilerplate of {-# LANGUAGE NoImplicitPrelude #-} (or `import Prelude()') and importing the custom one; this would still require ensuring that students had the custom prelude installed on their own laptops, etc.

b) write wrappers around ghc and ghci to load up the custom prelude instead, though even if we managed to get this to work we'd still need to somehow make sure all students would install equivalent wrappers on their own machine... and considering how much luck we've had with making sure they configured their editors to have the tab key insert four spaces instead of a tab character, I can see that being painful.

Either way, we'd then find ourselves teaching a "custom" version of Haskell, and I don't exactly have fond memories of when I was taught Java in my first year of uni using a custom wrapper/library (and since my only programming experience to date was Pascal/Delphi, I can't really blame Java :p)

I do, however, think that the Prelude is over-crowded and that Data.List should contain most of the list-specific functions (and it is weird when there is so much overlap between the two).

So my actual votes for the current status of this proposal are:

-1 for generalising the Prelude +1 for removing stuff from the Prelude (then people can import Data.List, Data.Traversable, Data.Foldable, etc. as they see fit without clashes) -1 for adding monomorphic stuff -0.5 for doing nothing

...

Regards, Malcolm.

On 22/05/2013, at 22:16, Herbert Valerio Riedel wrote:

...

+1 Generalize Prelude -1 Remove from Prelude -1 Add more monomorphic stuff -1 Do nothing +1 More fun polls like this

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