Re: BEGIN {} question
On 9/2/22 18:14, ToddAndMargo via perl6-users wrote:
On 9/2/22 13:52, ToddAndMargo via perl6-users wrote:
On 9/2/22 00:13, ToddAndMargo via perl6-users wrote:
Found something interesting
$ raku -c GetUpdates.pl6
Syntax OK
Will execute the BEGIN {}, not just
syntax check it.
The guys on the chat line said this is normal
as `BEGIN` runs a compile time
Hi All,
Thinking about it, I thought I did not bring
enough attention to the `-c` switch in the
above command line. This runs a SYNTAX check
and stops at that. It does not run the program.
I use the `-c` option extensively to debug my
typos before debugging my programs.
When I found BEGIN actually running when all
I wanted was a syntax check, I was perplexed.
My understanding was that -c only checked my
syntax, including my BEGIN block.
This is why I asked on the chat line. Bug
or suppose to be? And the answer is that
is just turned out that way. And that is
fine with me.
:-)
-T
Hi All,
For the fun of it, I placed a "booboo;"
in the BEGIN block to see what the syntax
checker would do:
$ raku -c GetUpdates.pl6
===SORRY!=== Error while compiling /home/linuxutil/GetUpdates.pl6
Undeclared routine:
booboo used at line 28
Caught it. No BEGIN pop up
Then I moved the booboo to the end of the
program
$ raku -c GetUpdates.pl6
===SORRY!=== Error while compiling /home/linuxutil/GetUpdates.pl6
Undeclared routine:
booboo used at line 11664
Caught it. And I also got the BEGIN's pop up.
Interesting!
:-)
-T
--
~~
Computers are like air conditioners.
They malfunction when you open windows
~~
Re: steps of a path
Marc Chantreux wrote:
>
> I got ([^1,^2,^3]) and tried to generalize it with something
> more generic (using * to get the number of elements).
Yeah, I was disappointed that that didn't work, and that what
did was relatively ugly, which is why I didn't bother to share it.
<<. raku -ne '.Str.say for m:ex{^ [:r "/" <-[/]>+]+? }'
The `.Str.say` can be just `.put`.
I'm surprised about your preference.
Is that because you're unfamiliar with Bruce's suggestion
(cumulative concat), or worry others will be unfamiliar with it?
If not, can you see why I'm surprised -- why `m:g{ "/" <-[/]>+ }`
seems simpler to me than `m:ex{^ [:r "/" <-[/]>+]+? }`?
--
raiph
Re: steps of a path
Hi Marc, There's also this conversation from March 2021 on the mailing list: https://www.nntp.perl.org/group/perl.perl6.users/2021/03/msg9857.html [Matthew's answer looks very interesting]. Anyway, HTH. --Bill. On Sat, Sep 3, 2022 at 2:51 PM Marc Chantreux wrote: > On Sat, Sep 03, 2022 at 09:50:08PM +0100, Ralph Mellor wrote: > > > ( A B C ) to ((A) (A B) (A B C)) ? > > [^1,^2,^3] > > I got that one and tried to generalize it with something more generic > (using * to get the number of elements). > > thanks for helping > > -- > Marc Chantreux > Pôle de Calcul et Services Avancés à la Recherche (CESAR) > http://annuaire.unistra.fr/p/20200 >
Re: steps of a path
On Sat, Sep 03, 2022 at 09:50:08PM +0100, Ralph Mellor wrote: > > ( A B C ) to ((A) (A B) (A B C)) ? > [^1,^2,^3] I got that one and tried to generalize it with something more generic (using * to get the number of elements). thanks for helping -- Marc Chantreux Pôle de Calcul et Services Avancés à la Recherche (CESAR) http://annuaire.unistra.fr/p/20200
Re: steps of a path
Hi Bruce and William,
Ineed: I was looking for [\,] but your code removes the anoying empty
string because of the leading / (which is awesome) so I mixed from both
answers (<-[/]> is more robust than .alpha ) and added .Str to .say.
finally I got:
<<. raku -ne '.Str.say for m:ex /^ ["/" <-[/]>+:] **? 1..* /;'
/var/log/messages
ther is only one caracter I don't understand in this anwser so I
considered removing it. bad idea:
<<. raku -ne '.Str.say for m:ex /^ ["/" <-[/]>+ ] **? 1..* /;'
/var/log/messages
so I read about backtracking and found something I found a bit easier
to get/memorize: the :r adverb.
<<. raku -ne '.Str.say for m:ex{ ^ [ :r "/" <-[/]>+ ] **? 1..* }'
/var/log/messages
last but not least: **? 1..* is just +?. At this point, my prefered solution
is:
<<. raku -ne '.Str.say for m:ex{^ [:r "/" <-[/]>+]+? }'
/var/log/messages
and it is pretty good compared to the sed version:
<<. sed -E ':b p; s:/[^/]+$::; t b'
thank you very much to both of you: I learned a lot on this post.
--
Marc Chantreux
Pôle de Calcul et Services Avancés à la Recherche (CESAR)
http://annuaire.unistra.fr/p/20200
Re: steps of a path
On Sat, Sep 3, 2022 at 9:50 PM Ralph Mellor wrote:
>
> .put for [\~] '/A/B/C' ~~ m:g { '/'? <-[/]>+ }
That won't match just a slash (`/`). Maybe:
.put for [\~] '/A/B/C' ~~ m:g { ('/'? <-[/]>*) }
And it'll treat `/a/b` and `/a/b/` as distinct if the input string is `/a/b/`.
--
raiph
Re: steps of a path
On Sat, Sep 3, 2022 at 9:50 PM Ralph Mellor wrote: > > it makes more sense to do something like Bruce or Michel's solutions. s/Michel/William/ -- raiph
Re: steps of a path
On Sat, Sep 3, 2022 at 6:17 PM Marc Chantreux wrote:
>
> ( A B C ) to ((A) (A B) (A B C)) ?
[^1,^2,^3]
I could share a generalization but it's pretty ugly and I also think
it makes more sense to do something like Bruce or Michel's solutions.
Here's my variation:
.put for [\~] '/A/B/C' ~~ m:g { '/'? <-[/]>+ }
--
raiph
Re: steps of a path
Hi Marc (and Bruce)!
Okay, I use our old friend `:exhaustive` adverb below:
~$ echo "/var/log/messages" | raku -ne '.say for m:ex/ ^ ["/"
<.alpha>+:]**?{1..*} /;'
｢/var｣
｢/var/log｣
｢/var/log/messages｣
If you remove the `?` frugal quant-modifier, the output is the same--except
in the reverse order.
HTH, Bill.
On Sat, Sep 3, 2022 at 12:45 PM Bruce Gray wrote:
>
> > On Sep 3, 2022, at 12:17 PM, Marc Chantreux wrote:
>
> --snip--
>
> > I thought the raku one could be shorter
>
> It will be hard to beat the brevity of a language with single-character
> instructions.
>
> --snip--
>
> > I'm pretty sure I saw a very concise and elegant way to transform
> > ( A B C ) to ((A) (A B) (A B C))
>
> Perhaps you are remembering `produce()`, also called "triangular reduce":
> https://docs.raku.org/routine/produce
> https://docs.raku.org/language/operators#Reduction_metaoperators
>
> $ raku -e 'say [\,] ;'
> ((A) (A B) (A B C))
>
> $ echo /var/log/messages | raku -ne '.say for [\~] .comb: /\/<-[/]>+/;'
> /var
> /var/log
> /var/log/messages
>
> --
> Hope this helps,
> Bruce Gray (Util of PerlMonks)
>
>
Re: steps of a path
> On Sep 3, 2022, at 12:17 PM, Marc Chantreux wrote: --snip-- > I thought the raku one could be shorter It will be hard to beat the brevity of a language with single-character instructions. --snip-- > I'm pretty sure I saw a very concise and elegant way to transform > ( A B C ) to ((A) (A B) (A B C)) Perhaps you are remembering `produce()`, also called "triangular reduce": https://docs.raku.org/routine/produce https://docs.raku.org/language/operators#Reduction_metaoperators $ raku -e 'say [\,] ;' ((A) (A B) (A B C)) $ echo /var/log/messages | raku -ne '.say for [\~] .comb: /\/<-[/]>+/;' /var /var/log /var/log/messages -- Hope this helps, Bruce Gray (Util of PerlMonks)
steps of a path
hello people,
I have this steps() function implemented this way in shell:
steps() sed -r ':b p; s,/[^/]+$,,; t b'
# demo:
<<. steps | xargs ls -lUd
/var/log/messages
which shows
-rw-r- 1 root adm 464304 Sep 3 19:03 /var/log/messages
drwxr-xr-x 22 root root 4096 Sep 3 00:00 /var/log
drwxr-xr-x 14 root root 4096 Jun 19 2021 /var
for those who don't know sed that much, the perl equivalent is:
steps() perl -lpe 'do {print} while s,/[^/]+$,,'
I thought the raku one could be shorter but for now I'm stuck
with a very long solution.
my \path = [ "/var/log/messages" .split: "/" ];
.say for (^path).map( { path[0..$_].join: "/" } )[1..*];
I'm pretty sure I saw a very concise and elegant way to transform
( A B C ) to ((A) (A B) (A B C)) in the past but I'm enable to figure
out how. Any help on that ?
thanks by advance.
--
Marc Chantreux
Pôle de Calcul et Services Avancés à la Recherche (CESAR)
http://annuaire.unistra.fr/p/20200
