1 files changed, 96 insertions, 0 deletions
diff --git a/challenge-323/jo-37/perl/ch-1.pl b/challenge-323/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..4963dc1fe1
--- /dev/null
+++ b/challenge-323/jo-37/perl/ch-1.pl
@@ -0,0 +1,96 @@
+#!/usr/bin/perl
+
+use v5.26;
+use Test2::V0 -no_srand;
+use Test2::Tools::Subtest 'subtest_streamed';
+use Getopt::Long;
+use experimental 'signatures';
+
+use List::Util qw(reduce sum0);
+
+
+### Options and Arguments
+
+my ($tests, $examples, $verbose);
+GetOptions(
+    'examples!' => \$examples,
+    'tests!'    => \$tests,
+    'verbose!'  => \$verbose,
+) or usage();
+
+run_tests($examples, $tests);	# tests do not return
+
+usage() unless @ARGV;
+
+sub usage {
+    die <<~EOS;
+    $0 - increment decrement
+
+    usage: $0 [-examples] [-tests] [-- op...]
+
+    -examples
+        run the examples from the challenge
+     
+    -tests
+        run some tests
+
+    op...
+        operations consisting of 'x++', '++x', 'x--' or '--x'
+
+    EOS
+}
+
+
+### Input and Output
+
+say inc_dec(@ARGV);
+
+
+### Implementation
+#
+# For details see:
+# https://github.sommrey.de/the-bears-den/2025/05/30/ch-323.html#task-1
+
+
+sub inc_dec {
+    sum0 map /^(?=.{3}$)x?([-+])\1x?$/ && "${1}1", @_
+}
+
+
+### Examples and Tests
+
+sub run_tests ($examples, $tests) {
+    return unless $examples || $tests;
+
+    state sub run_example ($args, $expected, $name) {
+        my $result = inc_dec(@$args);
+        is $result, $expected,
+            "$name: (@$args) -> $expected";
+    }
+
+    plan 2;
+
+    $examples ? subtest_streamed(examples => sub {
+        my @examples = (
+            [["--x", "x++", "x++"], 1, 'example 1'],
+            [["x++", "++x", "x++"], 3, 'example 2'],
+            [["x++", "++x", "--x", "x--"], 0, 'example 3'],
+        );
+        plan scalar @examples;
+        for (@examples) {
+            run_example @$_;
+        }
+    }) : pass 'skip examples';
+
+    $tests ? subtest_streamed(tests => sub {
+        plan 6;
+        is inc_dec(qw(++y y++)), 0, 'invalid inc';
+        is inc_dec(qw(--y y--)), 0, 'invalid dec';
+        is inc_dec(qw(+x x+)), 0, 'invalid inc';
+        is inc_dec(qw(-x x-)), 0, 'invalid dec';
+        is inc_dec(qw(++x++x)), 0, 'two in one';
+        is inc_dec(qw(+-x)), 0, 'mixed';
+    }) : pass 'skip tests';
+
+    exit;
+}