A concept is valid in Perl only if it can be shown to work in one line.
-- Inline::C::Cookbook

perl -MUnicode::UCD=prop_invlist -MString::Range::Expand=expand_expr -
+MList::Util=pairmap -E 'say join(",", sort map {chr} expand_expr(join
+(",", pairmap{"[$a-".($b-1)."]"} prop_invlist("PosixAlpha"))))'
A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,a,b,c,d,e,f,g,h,i,
+j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z

[download]

This isn't better than other solutions here, nor well golfed. It's just for fun.

I did want to show what code led to this one liner, though, as it shows some of the tricks we can derive from CPAN:

use strict;
use warnings;
use Unicode::UCD qw(prop_invlist);
use String::Range::Expand qw(expand_expr);
use List::Util qw(pairmap);

my @invlist = prop_invlist('PosixAlpha');
my $to_expand = join(',', pairmap {"[$a-" . ($b-1) . ']'} @invlist);
my @chars = sort map {chr $_} expand_expr($to_expand);

print join(',', @chars), "\n";

[download]

This produces the same output as above.

The only tricky part is that prop_invlist returns a list in the notation represented by [$a..$z), or in other words the start to one past the end. Consequently we need to pass $b-1 to expand_expr.


Dave

In reply to Re: Inspect the members of a Posix Character Class by davido
in thread Inspect the members of a Posix Character Class by NERDVANA

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