1 files changed, 63 insertions, 0 deletions
diff --git a/challenge-045/jo-37/perl/ch-1.pl b/challenge-045/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..9e5723b23b
--- /dev/null
+++ b/challenge-045/jo-37/perl/ch-1.pl
@@ -0,0 +1,63 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0 '!float';
+use PDL;
+use PDL::Char;
+use experimental 'signatures';
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV == 1;
+usage: $0 [-examples] [-tests] [PLAIN]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+PLAIN
+    plaintext to be square secret encoded
+
+EOS
+
+
+### Input and Output
+
+say "@{square_secret(shift)}";
+
+
+### Implementation
+
+sub square_secret ($s) {
+    # Transform to lowercase and remove blanks.
+    my $plain = PDL::Char->new($s =~ tr/A-Z /a-z/dr);
+    # Split the string into single characters and rearrange them to a
+    # 8xN matrix, transpose and join the rows to strings. Then return
+    # each string individually.
+    [map $_->atstr(0),
+        $plain->reshape(1, 8, ceil $plain->dim(0) / 8)
+        ->xchg(1, 2)->clump(0, 1)->dog];
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is square_secret('The quick brown fox jumps over the lazy dog'),
+        [qw(tbjrd hruto eomhg qwpe unsl ifoa covz kxey)], 'example';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}