Solution to task 1

1 files changed, 65 insertions, 0 deletions

diff --git a/challenge-237/jo-37/perl/ch-1.pl b/challenge-237/jo-37/perl/ch-1.pl
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+++ b/challenge-237/jo-37/perl/ch-1.pl
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+#!/usr/bin/perl -s
+
+use v5.24;
+use Test2::V0;
+use Date::Manip::Recur;
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV == 4;
+usage: $0 [-examples] [-tests] [YEAR MONTH NTH DOW]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+YEAR MONTH NTH DOW
+    find the day of month for the n-th occurence of the given day of
+    week in year and month.
+
+EOS
+
+
+### Input and Output
+
+say seize_the_day(@ARGV);
+
+
+### Implementation
+
+# Though the primary use of Date::Manip::Recur is the specification of
+# recurring events, it provides a concise description of single events,
+# too.  In the context of this task it is "the n-th occurrence of a
+# specific weekday in a given year and month".  There is one such event
+# at most, where we pick the day of month from, if it exists.
+sub seize_the_day {
+    local $" = ':';
+	my ($date) = Date::Manip::Recur->new("*@_:0:0:0")->dates;
+    $date ? ($date->value)[2] : 0;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is seize_the_day(2024, 4, 3, 2), 16, 'example 1';
+        is seize_the_day(2025, 10, 2, 4), 9, 'example 2';
+        is seize_the_day(2026, 8, 5, 3), 0, 'example 3';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        is seize_the_day(2023, 6, 1, 3), 7, '2023-06-07';
+	}
+
+    done_testing;
+    exit;
+}