Solution to task 1

1 files changed, 80 insertions, 0 deletions

diff --git a/challenge-158/jo-37/perl/ch-1.pl b/challenge-158/jo-37/perl/ch-1.pl
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+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use Math::Prime::Util qw(prime_iterator is_prime vecsum todigits);
+use Coro::Generator;
+use Syntax::Keyword::Gather;
+use experimental 'signatures';
+
+our ($tests, $examples, $base);
+$base ||= 10;
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [-base=B] [LIM]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+-base=B
+    Use number representation in given base.
+
+LIM
+    Print additive primes below given limit.
+
+EOS
+
+
+### Input and Output
+
+say for additive_primes_below(shift, $base);
+
+
+### Implementation
+
+sub additive_primes_below ($limit, $base = 10) {
+    my $p_i = prime_iterator();
+
+    # Build a generator for additive primes in the given base.
+    my $ap_i = generator {
+        my $p;
+        while () {
+            yield $p if is_prime vecsum todigits $p = $p_i->(), $base;
+        }
+    };
+
+    # Collect all additive primes below the given limit.
+    gather {
+        my $ap;
+        take $ap while ($ap = $ap_i->()) < $limit;
+    };
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is scalar additive_primes_below(100),
+        [2, 3, 5, 7, 11, 23, 29, 41, 43, 47, 61, 67, 83, 89],
+        'task 1';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        is scalar additive_primes_below(32, 2),
+        [3, 5, 7, 11, 13, 17, 19, 31],
+        'pernicious primes';
+	}
+
+    done_testing;
+    exit;
+}