+1 for temporarily
On Sat, Feb 18, 2023 at 4:34 AM Marc Nieper-Wißkirchen <
marc.nie...@gmail.com> wrote:
> As no one has complained so far, I have decided to go with `temporarily'.
>
> Am Do., 2. Feb. 2023 um 21:02 Uhr schrieb Marc Nieper-Wißkirchen
> <marc.nie...@gmail.com>:
> >
> > What about "temporarily" instead of the quite general "with"?
> >
> > So, for example:
> >
> > (temporarily
> > ((current-directory "/home/marc/scheme"))
> > <some code>)
> >
> > Marc
> >
> > Am So., 20. Nov. 2022 um 13:17 Uhr schrieb Shiro Kawai <
> shiro.ka...@gmail.com>:
> > >
> > > Ah, OK. Gauche's original parameterize works like 'with' in the sense
> that it can also accep a procedure with zero or one arguments. It still
> behaves differently if a parameter object has a non-idempotent converter,
> but such usage is rare, and for Gauche users it can be said that 'with'
> works mostly like the original 'parameterize'. However, thinking of RnRS
> parameterize, 'with' is certainly a different construct.
> > >
> > > Now I see 'with' as a generalization of 'with-*' style procedures that
> temporarily alter dynamic state. It encapsulates the typical pattern of
> using dynamic-wind to manage the dynamic states. If I frame it that way,
> the name 'with' fits well.
> > >
> > > The way srfi-226 currently worded looks like 'with' is another
> variation of 'parameterize', with a bonus of allowing parameter-like
> objects. How about introducting 'with' with the statement like this:
> Sometimes dynamic state can be managed by a procedure that works like a
> parameter; when it is called with no arguments it returns the current
> value, and wien it is called with one argument, val, it makes val as the
> current value. Combined with dynamic-wind, the state can be changed in a
> certain dynmaic scope. The 'with' form codifies that pattern. [...] Unlike
> parameterize, restoration of value is always done by calling parameter-like
> objects, allowing parameter-like objects to manipulate external state as
> well as the associated value.'
> > >
> > >
> > >
> > >
> > >
> > > On Sat, Nov 19, 2022 at 9:24 PM Marc Nieper-Wißkirchen <
> marc.nie...@gmail.com> wrote:
> > >>
> > >> "with" is not meant as a legacy mechanism because parameterize
> > >> changed. As the small language has no delimited continuations, SRFI
> > >> 226's parameterize is backward-compatible to the small language's.
> > >>
> > >> "With", on the other hand, is not a form of parameterize because it
> > >> behaves differently when the converter procedure of parameter objects
> > >> is not idempotent. Use cases for "with" are when parameter-like
> > >> objects need to do something non-trivial when the dynamic extent of
> > >> the "with" form is left. For example, there could be a parameter-like
> > >> object "current-directory", which changes the current directory on the
> > >> OS level in parallel. This cannot be done with parameterize and
> > >> ordinary parameter objects.
> > >>
> > >> In some sense, "with" is more general, but has no tail context
> > >> guarantee (and behaves differently wrt delimited continuations).
> > >>
> > >> Am So., 20. Nov. 2022 um 00:00 Uhr schrieb Shiro Kawai <
> shiro.ka...@gmail.com>:
> > >> >
> > >> >
> > >> >
> > >> > On Sat, Nov 19, 2022 at 12:51 AM Marc Nieper-Wißkirchen <
> marc.nie...@gmail.com> wrote:
> > >> >>
> > >> >>
> > >> >> Chez Scheme's "with" is only used in a deprecated macro facility
> > >> >> ("extend-syntax"). I think, at least for the purpose of Chez, it
> is
> > >> >> safe to reuse the identifier.
> > >> >>
> > >> >> The identifier "with" is undoubtedly quite general, but so are
> "let"
> > >> >> or "receive". I would be glad if "parameterize" had a shorter or
> less
> > >> >> complicated name.
> > >> >
> > >> >
> > >> > I see. Actually, if 'with' is used for dynamic binding (current
> srfi-226's parameterize), it is a reasonable name compared with let.
> > >> > In srfi-226, however, I got an impression that 'parameterize' is
> given to the true dynamic bindings, while 'with' is a kind of pseudo
> mechanism, mostly to accommodate the existing code that uses parameter-like
> objects in place of parameters. Yet, it has a shorter name and encourages
> users to use it over 'parameterize'.
> > >> >
> > >> > I thought it'd be ok before I noticed the subtle difference
> regarding shift/reset. I'm for providing a dynamic-wind based mechanism
> for the backward compatibility of legacy 'parameterize', but I'm afraid
> that naming it 'with' gives an impression that it is a more general,
> higher-level construct. (It is more general in a sense that it accepts
> parameter-like objets, but the semantics differ.)
> > >> >
> > >> > In other words: I'm going to tell Gauche users that the new
> 'parameterize' is not compatible with legacy 'parameterize', it will work
> most of the time but may behave differently in complicated cases; if you
> need a full compatibility you have to replace 'parameterize' for 'with'.
> I'm afraid that the users then think "ok, then I'm going to use 'with' for
> all dynamic bindings without worrying about compatibility, and it has a
> shorter name so it's even better." It's not desirable situation.
> > >> >
> > >> >
> > >> >
> > >> >
>
