Re: "Missing" libraries/concepts found in other languages/ecosystems?

[Chris Vine <vine35792468@gmail.com>]

On Fri, 10 Jul 2020 10:49:37 +0200
Catonano <catonano@gmail.com> wrote:
> Il giorno mer 8 lug 2020 alle ore 20:22 Zelphir Kaltstahl <
> zelphirkaltstahl@gmail.com> ha scritto:
> 
> > Hi Simen!
> >
> > On 7/8/20 6:00 PM, guile-user-request@gnu.org wrote:
> > > Hi, I'm new to scheme/lisp, so I'm trying to find out how to do
> > > things the "lisp
> > > way". On the other hand, I like things from other ecosystems too,
> > > and I'm having
> > > problems finding this for Guile. It might be because there's no
> > > need for it/I'm
> > > terrible at searching/nobody had the time yet, or something else.
> > >
> > > I've been trying to find implementations for https://reactivex.io
> > > without any
> > > luck. And I'm unable to find implementation of FP concepts as
> > > found in Haskell
> > > and other languages. Functor, Monad, lenses (and other helpers for
> > > working with
> > > immutable data).
> > >
> > > Does things like this exists, or is it better to use something
> > > else?
> > >
> > > Regards Simen
> >
> > To what others already have written I will add:
> >
> > From time to time one can copy ideas from Racket or look at what exists
> > in Racket for solving a problem or seeing what the approach is.
> >
> > Catonano identified already the lack of examples in the Guile guide. I
> > fight with that myself, so I created a repository with examples. Perhaps
> > I should somehow add them to the guide. I've not looked into how to do
> > that. Probably some commit in a repo somewhere for the guide:
> >
> > https://notabug.org/ZelphirKaltstahl/guile-examples
> >
> > Hope this can help!
> >
> 
> Thank you, yes that helps
> 
> In fact, it's a precious resource !
> 
> I was especially delighted with the examples of using exceptions !
> 
> I had so missed examples of those !
> 
> As for the manual, very recently a mention of Guile Hall ended up being
> included in the manual
> 
> The same could be done with your examples collection
> 
> I also think that your collection could be mentioned by the Guile web site,
> maybe in the "learn" section
> 
> Here's the repo for the web site:
> https://git.savannah.gnu.org/cgit/guile/guile-web.git/
> 
> a regular patch could do
> 
> What do people think of mentioning this resource on the Guile web site ?

Whilst I don't have strong feelings, as a general approach I think it is
better to include additional examples (where needed) in the body of the
manual, which I think is generally well written.

Also, at this level of detail what some find helpful others don't.  You
were delighted above with the exceptions example, whereas (if I read
the right one) I thought that that was one of the weaker ones.  It
concentrates on R6RS/R7RS exceptions and with-exception-handler rather
than with guile's much easier to use catch expression (for guile-2.2)
or (for guile-3.0) its beefed-up with-exception-handler and exception
objects.

with-exception-handler is a tricky beast and the example didn't deal
with the main case: most uses of exceptions involve handling them and
moving on with program execution from the point where the exception is
caught, and to do that using with-exception-handler instead of
guile's 'catch' form you have to have a call/ec helper (or with
guile-3.0 you can just set the #unwind argument to true).  Instead you
are left with the idea that you use continuable exceptions for that
(which while they do stop the program exiting are something different)
or the R6RS/R7RS guard form.

I am not trying to be critical here - I think examples are useful to
convey points and some of them were fine.  My point is more about venue.