Re: [libgpiod v2][PATCH v3 2/4] bindings: python: add examples

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Mon, Oct 17, 2022 at 4:19 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> On Mon, Oct 17, 2022 at 10:07:17PM +0800, Kent Gibson wrote:
> > On Mon, Oct 17, 2022 at 04:49:55PM +0300, Andy Shevchenko wrote:
> > > On Mon, Oct 17, 2022 at 08:11:28PM +0800, Kent Gibson wrote:
> > > > On Mon, Oct 17, 2022 at 02:00:15PM +0200, Bartosz Golaszewski wrote:
> > > > > On Thu, Oct 13, 2022 at 5:09 AM Kent Gibson <warthog618@xxxxxxxxx> wrote:
> > > > > > On Fri, Oct 07, 2022 at 04:55:19PM +0200, Bartosz Golaszewski wrote:
>
> ...
>
> > > > > >         lvs = [ arg.split('=') for arg in sys.argv[2:] ]
> > > >             lvs = [ (x,int(y)) for (x,y) in lvs ]
> > > > > >         lines = [ x[0] for x in lvs ]
> > > > > >         values = dict(lvs)
> > > > >
> > > >
> > > > An extra pass to fix the int values.
> > >
> > > In Python we have map(), which I think is the best for that kind of job.
> > >
> >
> > My understanding is map/filter is old school and list comprehensions
> > have replaced map, as generators have replaced filter.
> >
> > i.e.
> >     list(map(function, iterable))
> > becomes
> >     [function(x) for x in iterable]
>
> Definitely it does not cover all the cases map() is taking care of.
> So it can't be old school :-)
>
> * Yes, in this particular case it may be map() or list comprehension.
>   But I think with map() the two lines can become one.
>
> > Either way, what we are missing here is a parser function that gives us
> > exactly the (offset,value) output we want from the command line string.
> >
> > Oh, and we need both the lines list and the values dict, both of which
> > are easily created from the interim lvs.
> >
> > > > You could do it in one with a more appropriate parser function.
> > >
> > > It seems we need some Python guru to revisit the code, because to me
> > > it looks a bit C:ish :-)
> >
> > The for loop or the list comprehension?
> > Last I checked only one of those is available in C.
> > And yeah, the for loop version reads as C, so not at all Pythonic,
> > which is why I suggested the list comprehension.
>
> Yes, but I believe it does not utilize the powerfulness of the current Python.
> Anyway, I'm not a Py guru, take my remarks with a grain of salt.
>

How about this?

    lvs = list(
        map(
            lambda val: [val[0], Value(int(val[1]))],
            [arg.split("=") for arg in sys.argv[2:]],
        )
    )
    lines = [x[0] for x in lvs]
    values = dict(lvs)

It's so much less readable but at least it's pythonic, look at those
lambdas and comprehension lists and even a map! :)

Anyway - unlike the programming interface - these are just
implementation details that can be always improved later.

Bart