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Postings from October 2021
* Dan Book <grinnz@gmail.com> [2021-10-19 20:48:15 -0400]:
> On Tue, Oct 19, 2021 at 7:45 PM Oodler 577 via perl5-porters <
> perl5-porters@perl.org> wrote:
>
> > * hv@crypt.org <hv@crypt.org> [2021-10-19 21:49:47 +0100]:
> >
> > > "Paul \"LeoNerd\" Evans" <leonerd@leonerd.org.uk> wrote:
> > > [...]
> > > : try {
> > > : ## 100 lines here
> > > : }
> > > : finally {
> > > : say "Oh and just do this before you go"
> > > : }
> > > [...]
> > > : {
> > > : ## 100 lines here
> > > : }
> > > : finally {
> > > : say "Oh and just do this before you go"
> > > : }
> >
> > Replying to Hugo's comment only to honor it; but in the case of
> > the bare block this seems like a NOOP unless "finally" implies a
> > "wait" or waitpid for thing, but I don't know what things that
> > could be other than a child process spawned by either C<fork> or
> > an explict background shell command via C<system> or C<``> or
> > C<qx//>, etc.
> >
> > LABEL:
> > {
> > # do stuff
> > # spawn a child proc
> > }
> > finally {
> > # do more stuff but what's
> > # the state of child process?
> > }
> >
> > 1. when does `finally` get executed, does it wait for child pid?
> > 2. does LABEL: work as expected if one does, `next LABEL;`?
> >
>
> Forking has no relevance to the concept. The difference finally makes, as
> with defer, is that it runs when the associated scope is exited, even if
> it's done so via an exception, loop control, etc.
I guess I don't understand the value of providing this for a bare block,
and the only value I can see in any other block structure is to extend
scope "one more time".
# currently
my $i;
for $i (1..10) {
# do stuff
}
if ($i < 10) {
print qq{Loop exited early!\n};
}
versus
# with 'finally'
for my $i (1..10) {
# do stuff
}
finally {
if ($i < 10) {
print qq{Loop exited early!\n};
}
}
Similarly, I see value in extending this to the block form of eval,
local $@;
my $ret = eval {
my $inner_var = q{asdf};
#... do stuf that might die
}
finally {
print qq{$inner_var};
}
#$@ and $ret available here, $inner_var is not
#...
It also seems to provide the corollary to do { .. } while (), which provides
an in scope "pre step" versus a basic while () { ... }.
So maybe to be consist, the "finally" on a "while" should be like,
while (...) {
}
do {
}
Or maybe, "finally" should just be "done" for all,
while (...) {
}
done {
}
or
try {
}
catch {
}
done {
}
or
for my $i (1..10) {
}
done {
}
etc
Thanks,
Brett
>
> -Dan
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