And when I cut/paste from the doc, the number example works too, in both script and repl.
On Wed, Mar 17, 2021 at 10:33 PM Ralph Mellor <ralphdjmel...@gmail.com> wrote: > > Er, by wfm I mean it matches ｢Is｣ as the code suggests. > > On Wed, Mar 17, 2021 at 10:32 PM Ralph Mellor <ralphdjmel...@gmail.com> wrote: > > > > Works for me in Rakudo 2020.12. > > > > On Wed, Mar 17, 2021 at 9:33 PM yary <not....@gmail.com> wrote: > > > > > > The "Interpolation" section of the raku docs use strings as the elements > > > of building up a larger regex from smaller pieces, but the example that > > > looks fruitful isn't working in my raku. This is taken from > > > https://docs.raku.org/language/regexes#Regex_interpolation > > > > > > > my $string = 'Is this a regex or a string: 123\w+False$pattern1 ?'; > > > > > > Is this a regex or a string: 123\w+False$pattern1 ? > > > > > > > my $regex = /\w+/; > > > > > > /\w+/ > > > > > > > say $string.match: / $regex /; > > > > > > Regex object coerced to string (please use .gist or .raku to do that) > > > > > > ... and more error lines, and no result when the docs show matching > > > '123': > > > > > > ｢｣ > > > > > > > > > $ raku -v > > > > > > Welcome to 𝐑𝐚𝐤𝐮𝐝𝐨™ v2020.10. > > > > > > Implementing the 𝐑𝐚𝐤𝐮™ programming language v6.d. > > > > > > Built on MoarVM version 2020.10. > > > > > > > > > > > > -y > > > > > > > > > On Wed, Mar 17, 2021 at 3:17 PM William Michels via perl6-users > > > <perl6-us...@perl.org> wrote: > > >> > > >> Dear Brad, > > >> > > >> 1. The list you posted is fantastic ("If the first character inside is > > >> anything other than an alpha it doesn't capture"). It should be added to > > >> the Raku Docs ASAP. > > >> > > >> 2. There are some shortcuts that don't seem to follow a set pattern. For > > >> example a named capture can be accessed using $<myname> instead of > > >> $/<myname> ; the "/' can be elided. Do you have a method you can share > > >> for remembering these sorts of shortcuts? Or are they disfavored? > > >> > > >> > say ~$<myname> if 'abc' ~~ / $<myname> = [ \w+ ] /; > > >> abc > > >> > > > >> [ Above from the example at > > >> https://docs.raku.org/syntax/Named%20captures ]. > > >> > > >> 3. Finally, I've never seen in the Perl6/Raku literature the motto you > > >> cite: "One of the mottos of Raku, is that it is ok to confuse a new > > >> programmer, it is not ok to confuse an expert." Do you have a citation? > > >> > > >> [ The motto I prefer is from Larry Wall: "...easy things should stay > > >> easy, hard things should get easier, and impossible things should get > > >> hard... ." Citation: https://www.perl.com/pub/2000/10/23/soto2000.html/ > > >> ]. > > >> > > >> Best Regards, > > >> > > >> Bill. > > >> > > >> > > >> > > >> On Sat, Mar 13, 2021 at 4:47 PM Brad Gilbert <b2gi...@gmail.com> wrote: > > >>> > > >>> It makes <…> more consistent precisely because <$pattern> doesn't > > >>> capture. > > >>> > > >>> If the first character inside is anything other than an alpha it > > >>> doesn't capture. > > >>> Which is a very simple description of when it captures. > > >>> > > >>> <?before …> doesn't capture because of the ｢?｣ > > >>> <!before …> doesn't capture because of the ｢!｣ > > >>> <.ws> doesn't capture because of the ｢.｣ > > >>> <&ws> doesn't capture because of the ｢&｣ > > >>> <$pattern> doesn't capture because of the ｢$｣ > > >>> <$0> doesn't capture because of the ｢$｣ > > >>> <@a> doesn't capture because of the ｢@｣ > > >>> <[…]> doesn't capture because of the ｢[｣ > > >>> <-[…]> doesn't capture because of the ｢-] > > >>> <:Ll> doesn't capture because of the ｢:｣ > > >>> > > >>> For most of those, you don't actually want it to capture. > > >>> With ｢.｣ the whole point is that it doesn't capture. > > >>> > > >>> <digit> does capture because it starts with an alpha > > >>> <pattern=$pattern> does capture because it starts with an alpha > > >>> > > >>> $0 = <$pattern> doesn't capture to $<pattern>, but does capture to > > >>> $0 > > >>> $<pattern> = <$pattern> captures because of $<pattern> = > > >>> > > >>> It would be a mistake to just make <$pattern> capture. > > >>> Consistency is perhaps Raku's most important feature. > > >>> > > >>> One of the mottos of Raku, is that it is ok to confuse a new > > >>> programmer, it is not ok to confuse an expert. > > >>> An expert in Raku understands the deep fundamental ways that Raku is > > >>> consistent. > > >>> So breaking consistency should be very carefully considered. > > >>> > > >>> In this case, there is very little benefit. > > >>> Even worse, you then have to come up with some new syntax to prevent it > > >>> from capturing when you don't want it to. > > >>> That new syntax wouldn't be as guessible as it currently is. Which > > >>> again would confuse experts. > > >>> > > >>> If anyone seriously suggests such a change, I will vehemently fight to > > >>> prevent it from happening. > > >>> > > >>> I would be more likely to accept <=$pattern> being added as a synonym > > >>> to <pattern=$pattern>. > > >>> > > >>> On Sat, Mar 13, 2021 at 3:30 PM Joseph Brenner <doom...@gmail.com> > > >>> wrote: > > >>>> > > >>>> Thanks much for your answer on this. I think this is the sort of > > >>>> trick I was looking for: > > >>>> > > >>>> Brad Gilbert<b2gi...@gmail.com> wrote: > > >>>> > > >>>> > You can put it back in as a named > > >>>> > > >>>> > > $input ~~ / <pattern=$pattern> > > >>>> > ｢9 million｣ > > >>>> > pattern => ｢9 million｣ > > >>>> > 0 => ｢9｣ > > >>>> > 1 => ｢million｣ > > >>>> > > >>>> That's good enough, I guess, though you need to know about the > > >>>> issue... is there some reason it shouldn't happen automatically, > > >>>> using the variable name to label the captures? > > >>>> > > >>>> I don't think this particular gotcha is all that well > > >>>> documented, though I guess there's a reference to this being a > > >>>> "known trap" in the documentation under "Regex interpolation"-- > > >>>> but that's the sort of remark that makes sense only after you know > > >>>> what its talking about. > > >>>> > > >>>> I have to say, my first reaction was something like "if they > > >>>> couldn't get this working right, why did they put it in?" > > >>>> > > >>>> > > >>>> On 3/11/21, Brad Gilbert <b2gi...@gmail.com> wrote: > > >>>> > If you interpolate a regex, it is a sub regex. > > >>>> > > > >>>> > If you have something like a sigil, then the match data structure > > >>>> > gets > > >>>> > thrown away. > > >>>> > > > >>>> > You can put it back in as a named > > >>>> > > > >>>> > > $input ~~ / <pattern=$pattern> > > >>>> > ｢9 million｣ > > >>>> > pattern => ｢9 million｣ > > >>>> > 0 => ｢9｣ > > >>>> > 1 => ｢million｣ > > >>>> > > > >>>> > Or as a numbered: > > >>>> > > > >>>> > > $input ~~ / $0 = <$pattern> > > >>>> > ｢9 million｣ > > >>>> > 0 => ｢9 million｣ > > >>>> > 0 => ｢9｣ > > >>>> > 1 => ｢million｣ > > >>>> > > > >>>> > Or put it in as a lexical regex > > >>>> > > > >>>> > > my regex pattern { (\d+) \s+ (\w+) } > > >>>> > > $input ~~ / <pattern> / > > >>>> > ｢9 million｣ > > >>>> > pattern => ｢9 million｣ > > >>>> > 0 => ｢9｣ > > >>>> > 1 => ｢million｣ > > >>>> > > > >>>> > Or just use it as the whole regex > > >>>> > > > >>>> > > $input ~~ $pattern # variable > > >>>> > ｢9 million｣ > > >>>> > 0 => ｢9｣ > > >>>> > 1 => ｢million｣ > > >>>> > > > >>>> > > $input ~~ &pattern # my regex pattern /…/ > > >>>> > ｢9 million｣ > > >>>> > 0 => ｢9｣ > > >>>> > 1 => ｢million｣ > > >>>> > > > >>>> > On Thu, Mar 11, 2021 at 2:29 AM Joseph Brenner <doom...@gmail.com> > > >>>> > wrote: > > >>>> > > > >>>> >> Does this behavior make sense to anyone? When you've got a regex > > >>>> >> with captures in it, the captures don't work if the regex is > > >>>> >> stashed in a variable and then interpolated into a regex. > > >>>> >> > > >>>> >> Do capture groups need to be defined at the top level where the > > >>>> >> regex is used? > > >>>> >> > > >>>> >> { # From a code example in the "Parsing" book by Moritz Lenz, p. > > >>>> >> 48, > > >>>> >> section 5.2 > > >>>> >> my $input = 'There are 9 million bicycles in beijing.'; > > >>>> >> if $input ~~ / (\d+) \s+ (\w+) / { > > >>>> >> say $0.^name; # Match > > >>>> >> say $0; # ｢9｣ > > >>>> >> say $1.^name; # Match > > >>>> >> say $1; # ｢million｣ > > >>>> >> say $/; > > >>>> >> # ｢9 million｣ > > >>>> >> # 0 => ｢9｣ > > >>>> >> # 1 => ｢million｣ > > >>>> >> } > > >>>> >> } > > >>>> >> > > >>>> >> say '---'; > > >>>> >> > > >>>> >> { # Moving the pattern to var which we interpolate into match > > >>>> >> my $input = 'There are 9 million bicycles in beijing.'; > > >>>> >> my $pattern = rx{ (\d+) \s+ (\w+) }; > > >>>> >> if $input ~~ / <$pattern> / { > > >>>> >> say $0.^name; # Nil > > >>>> >> say $0; # Nil > > >>>> >> say $1.^name; # Nil > > >>>> >> say $1; # Nil > > >>>> >> say $/; # ｢9 million｣ > > >>>> >> } > > >>>> >> } > > >>>> >> > > >>>> >> In the second case, the match clearly works, but it behaves as > > >>>> >> though the capture groups aren't there. > > >>>> >> > > >>>> >> > > >>>> >> raku --version > > >>>> >> > > >>>> >> Welcome to 𝐑𝐚𝐤𝐮𝐝𝐨™ v2020.10. > > >>>> >> Implementing the 𝐑𝐚𝐤𝐮™ programming language v6.d. > > >>>> >> > > >>>> >
