Challenge 047 task 2

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diff --git a/challenge-047/jo-37/perl/ch-2.pl b/challenge-047/jo-37/perl/ch-2.pl
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+++ b/challenge-047/jo-37/perl/ch-2.pl
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+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use Math::Prime::Util qw(fromdigits todigits);
+use List::Gen;
+use experimental qw(signatures);
+
+our ($tests, $examples, $base);
+$base //= 10;
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [N]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+N
+    print first N gapful numbers
+
+EOS
+
+
+### Input and Output
+
+gen_gapful($base)->say(shift);
+
+
+### Implementation
+
+sub gen_gapful ($base) {
+    my $start = $base**2;
+	<$start..>->filter(sub {
+            !($_ % fromdigits [(todigits $_, $base)[0, -1]], $base);
+        });
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+        
+        is gen_gapful(10)->take(20), [100, 105, 108, 110, 120, 121, 130,
+            132, 135, 140, 143, 150, 154, 160, 165, 170, 176, 180, 187,
+            190], 'task 2';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}