1 files changed, 64 insertions, 0 deletions
diff --git a/challenge-135/jo-37/perl/ch-1.pl b/challenge-135/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..e8049ba672
--- /dev/null
+++ b/challenge-135/jo-37/perl/ch-1.pl
@@ -0,0 +1,64 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use experimental 'signatures';
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [--] [N]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+N
+    Number. Use '-- -N' for negative numbers.
+
+EOS
+
+
+### Input and Output
+
+say middle_digits(shift);
+
+
+### Implementation
+
+sub middle_digits ($n) {
+    $n = int abs $n;
+    my $l = length $n;
+    die "even number of digits\n" unless $l % 2;
+    die "too short\n" unless $l >= 3;
+    substr $n, ($l - 3) / 2, 3;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is middle_digits(1234567), 345, 'example 1';
+        is middle_digits(-123), 123, 'example 2';
+        like dies {middle_digits(1)}, qr(too short), 'example 3';
+        like dies {middle_digits(12)}, qr(even number of digits), 'example 4';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        is middle_digits('0012345'), 234, 'ignore leading zeros';
+        is middle_digits(12345.67), 234, 'force float to integer';
+        is middle_digits(-12345.67), 234, 'force negative float to integer';
+	}
+
+    done_testing;
+    exit;
+}