Solution to task 2

1 files changed, 65 insertions, 0 deletions

diff --git a/challenge-287/jo-37/perl/ch-2.pl b/challenge-287/jo-37/perl/ch-2.pl
new file mode 100755
index 0000000000..27124c11b7
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+++ b/challenge-287/jo-37/perl/ch-2.pl
@@ -0,0 +1,65 @@
+#!/usr/bin/perl -s
+
+use v5.24;
+use Test2::V0;
+use Regexp::Common;
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [STR]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+STR
+    a string
+
+EOS
+
+
+### Input and Output
+
+say +(qw(true false))[!valid_number(shift)];
+
+
+### Implementation
+#
+# For details see:
+# https://github.sommrey.de/the-bears-den/2024/09/22/ch-287.html#task-2
+
+
+sub valid_number {
+	shift =~ /^$RE{num}{real}\z/;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        ok  valid_number("1"),       "example 1";
+        ok !valid_number("a"),       "example 2";
+        ok !valid_number("."),       "example 3";
+        ok !valid_number("1.2e4.2"), "example 4";
+        ok  valid_number("-1."),     "example 5";
+        ok  valid_number("+1E-8"),   "example 6";
+        ok  valid_number(".44"),     "example 7";
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        ok !valid_number("42\n"), "newline not allowed";
+	}
+
+    done_testing;
+    exit;
+}