From: Philippe Troin <phil@fifi.org>
To: zsh-workers@zsh.org
Subject: Re: PATCH: function copy
Date: Tue, 16 Jul 2019 09:55:56 -0700 [thread overview]
Message-ID: <11a8ebbdbe63f0c6303ab53deeffd17e9ae168a5.camel@fifi.org> (raw)
In-Reply-To: <1563267373.6702.5.camel@samsung.com>
On Tue, 2019-07-16 at 09:56 +0100, Peter Stephenson wrote:
> On Mon, 2019-07-15 at 14:42 -0700, Bart Schaefer wrote:
> > On Mon, Jul 15, 2019 at 1:00 PM Peter Stephenson
> > <p.w.stephenson@ntlworld.com> wrote:
> > >
> > >
> > > I've had this lying around for a while, wondering if there's more
> > > to it,
> > > but I can't think of it.
> > >
> > > The point is that it's very easy internally to provide an
> > > interface to
> > > tweak standard functions to add arbitrary code before and after
> > > --- we
> > > have most of the support for this internally, and just lack the
> > > means to
> > > add a different name for a function, which this adds.
> > Emacs calls this "advice" and allows before/around/after variations
> > which can be added without having to redefine the existing
> > function.
> > I have a half-finished (that may be optimistic) module to provide
> > this
> > for ZLE widgets. Handling the before/after is not too bad, but for
> > "around" you need a way to say "call the original function HERE"
> > which
> > you can then embed in another function that becomes the "around"
> > (and
> > which is called in place of the original everywhere except HERE).
>
> That's basically what I showed in my example.
>
> functions -c _std_fn _my_fn
> _std_fn() {
> # do stuff here
> _my_fn "$@"
> # do stuff here
> }
I've been using the following hackish idioms:
% foo() { print foo $@; }
% () {
local func=$functions[foo]
eval "foo() { print before foo; { $func }; print after foo }"
}
% foo bar
before foo
foo bar
after foo
and
% functions[foo_copy]=$functions[foo]
Of course these cause reparsing of the function body, so "function -c"
may still make sense.
I like the idea of a full advising system.
Phil.
next prev parent reply other threads:[~2019-07-16 16:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 20:00 Peter Stephenson
2019-07-15 20:23 ` Sebastian Gniazdowski
2019-07-15 21:25 ` Peter Stephenson
2019-07-15 21:42 ` Bart Schaefer
2019-07-15 21:51 ` Sebastian Gniazdowski
2019-07-15 22:08 ` Bart Schaefer
2019-07-16 8:56 ` Peter Stephenson
2019-07-16 16:55 ` Philippe Troin [this message]
2019-07-16 19:06 ` Bart Schaefer
2019-07-16 19:11 ` Bart Schaefer
2019-08-03 18:58 ` Peter Stephenson
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