1 files changed, 22 insertions, 0 deletions
diff --git a/challenge-273/e-choroba/perl/ch-2.pl b/challenge-273/e-choroba/perl/ch-2.pl
new file mode 100755
index 0000000000..3ebdf460d3
--- /dev/null
+++ b/challenge-273/e-choroba/perl/ch-2.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use experimental qw( signatures );
+
+sub b_after_a($str) {
+    $str =~ /^           # Start of the string.
+             [^b]*       # Anything up to the first b.
+             b           # The first b.
+             (?!         # Not folllowed by...
+                 .*      # ... anything...
+                 a       # ... and a.
+             )
+            /x
+}
+
+use Test::More tests => 4;
+
+ok b_after_a('aabb'), 'Example 1';
+ok ! b_after_a('abab'), 'Example 2';
+ok ! b_after_a('aaa'), 'Example 3';
+ok b_after_a('bbb'), 'Example 4';