Challenge 017 task 1

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diff --git a/challenge-017/jo-37/perl/ch-1.pl b/challenge-017/jo-37/perl/ch-1.pl
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+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use Memoize;
+use experimental 'signatures';
+no warnings 'recursion';
+
+memoize('ackermann');
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV == 2;
+usage: $0 [-examples] [-tests] [M N]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+M N
+    calculate ackermann(M, N)
+
+EOS
+
+
+### Input and Output
+
+say ackermann(@ARGV);
+
+
+### Implementation
+
+sub ackermann ($m, $n) {
+    return $n + 1 unless $m;
+    return ackermann($m - 1, 1) unless $n;
+	ackermann($m - 1, ackermann($m, $n - 1));
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is ackermann(1, 2), 4;
+        is ackermann(2, 3), 9;
+        is ackermann(3, 4), 125;
+        is ackermann(4, 0), 13;
+        is ackermann(4, 1), 65533;
+        is ackermann(5, 0), 65533;
+
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}