[Types-sig] RE: PRE-PROPOSAL: Python Interfaces

[Tim Peters]

[followups to types-sig@python.org, please]

[Guido "Trained as a Mathematician!" van Rossum]

> I just read Uche's objection against the current static type ideas.
> He mentions that he much favors John Skaller's proposal.
>
> Unfortunately, much as I try to read Skaller's prose, I don't
> understand a bit of it.

Given your middle name (see above), perhaps that says something about the
potential popular appeal of the approach -- I'm not sure "Teach Yourself
Functors from Abstract Categories in 21 Days!" or "Secrets of the Morphism
Masters!" are destined to top the SAMS best-seller list <wink>.

I last gave close attention to approaches "like this" when they were called
"algebraic specification of abstract datatypes" in the late 70s and early
80s.  Back then it was neat stuff and generated some interesting results.
But having cast programming into a formal system the temptation was to
forget the origin and play with the formal system for its own sake; later
efforts to reflect insights from the latter back into language design were
usually greeted with about as much enthusiasm as you'd expect given John's
"What is an instance? Any other category X which is the image of a functor
from [the abstract category corresponding to the thing you (in your charming
naivete <wink>) call "the class" today]".

Now *maybe* dumping category theory into the mix has profoundly altered this
disconnect from everyday practice -- but to judge from John's presentation,
it appears to have gotten worse.

> The only impression I get is that perhaps there's a counter-proposal
> in there to consider; however I have no idea what it is.
>
> Did anybody have more success in understanding it?  If so, I'd love it
> if you could post a summary...

I believe PaulP and JimF have both invited John to comment on the Scarecrow
Proposal, and it seems to me too that the SP *appears* to have a lot in
common with the protocols module John created for Interscript (the only
thing of his on the table I think qualifies as a concrete counter-proposal).

in-theory-theory-is-great-ly y'rs  - tim