From d5824dd24b4281c273548694ac0709e760384aa0 Mon Sep 17 00:00:00 2001
From: Joelle Maslak <jmaslak@antelope.net>
Date: Sat, 20 Jul 2019 22:03:49 -0600
Subject: Solution for 17.1.1 in P6 & P5

---
 challenge-017/joelle-maslak/perl5/ch-1.pl | 42 +++++++++++++++++++++++++++++++
 challenge-017/joelle-maslak/perl6/ch-1.p6 | 40 +++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100755 challenge-017/joelle-maslak/perl5/ch-1.pl
 create mode 100755 challenge-017/joelle-maslak/perl6/ch-1.p6

diff --git a/challenge-017/joelle-maslak/perl5/ch-1.pl b/challenge-017/joelle-maslak/perl5/ch-1.pl
new file mode 100755
index 0000000000..e1eae1c31a
--- /dev/null
+++ b/challenge-017/joelle-maslak/perl5/ch-1.pl
@@ -0,0 +1,42 @@
+#!/usr/bin/env perl
+use v5.22;
+use strict;
+use warnings;
+
+# Turn on method signatures
+use feature 'signatures';
+no warnings 'experimental::signatures';
+
+use autodie;
+use bigint;
+
+sub main() {
+    die "Usage: $0 <m> <n>" if @ARGV != 2;
+
+    say A(@ARGV);
+}
+
+sub A($m, $n) {
+    return $n + 1 if !$m;
+
+    if ( $m > 2 ) {
+        # Shortcut based on Wikipedia!
+        my $ret = 2;
+        $ret = up_arrow(2, $m-2, $n+3); 
+        return $ret - 3;
+    }
+
+    return A($m-1, 1) if !$n;
+    return A($m-1, A($m, $n-1));
+}
+
+sub up_arrow($m, $num_arrows, $n) {
+    no warnings 'recursion';
+    return 1 unless $n;
+    return $m ** $n if $num_arrows == 1;
+
+    @_ = ($m, $num_arrows-1, up_arrow($m, $num_arrows, $n-1));
+    goto &up_arrow;
+}
+
+main();
diff --git a/challenge-017/joelle-maslak/perl6/ch-1.p6 b/challenge-017/joelle-maslak/perl6/ch-1.p6
new file mode 100755
index 0000000000..236e54db22
--- /dev/null
+++ b/challenge-017/joelle-maslak/perl6/ch-1.p6
@@ -0,0 +1,40 @@
+#!/usr/bin/env perl6
+use v6;
+
+use experimental :cached;
+
+multi sub MAIN(:$test) {
+    use Test;
+
+    my @tests =
+        [ 1, 2, 4 ],
+        [ 3, 50, 9007199254740989 ],
+        [ 4, 2, (2 ** 2 ** 2 ** 2 ** 2) - 3 ],
+        [ 5, 0, 65533 ],
+    ;
+
+    for @tests -> $test {
+        is A($test[0], $test[1]), $test[2], "A($test[0],$test[1])";
+    }
+
+    done-testing;
+}
+
+multi sub MAIN(UInt:D $m, UInt:D $n) {
+   say A($m, $n);
+}
+
+multi sub A(0,                     UInt:D $n --> UInt:D) { $n + 1 }
+multi sub A(UInt:D $m,             0         --> UInt:D) { A( $m-1, 1 ) }
+
+# This is a shortcut based on Wikipedia information - lets me compute
+# A(5,0) for instance.
+multi sub A(UInt:D $m where * > 2, UInt:D $n --> UInt:D) { up-arrow(2, $m-2, $n+3) - 3 }
+
+multi sub A(UInt:D $m,             UInt:D $n --> UInt:D) { A( $m-1, A($m, $n-1) ) }
+
+multi sub up-arrow(UInt:D $m, UInt:D $num-arrows, 0         --> UInt:D) { 1 }
+multi sub up-arrow(UInt:D $m, 1,                  UInt:D $n --> UInt:D) { $m ** $n }
+multi sub up-arrow(UInt:D $m, UInt:D $num-arrows, UInt:D $n --> UInt:D) {
+    up-arrow($m, $num-arrows-1, up-arrow($m, $num-arrows, $n-1));
+}
-- 
cgit 


From 651a2c1a55ef0c7748151d6ad53786aa228998c8 Mon Sep 17 00:00:00 2001
From: Joelle Maslak <jmaslak@antelope.net>
Date: Sat, 20 Jul 2019 22:05:09 -0600
Subject: Minor code cleanup

---
 challenge-017/joelle-maslak/perl6/ch-1.p6 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/challenge-017/joelle-maslak/perl6/ch-1.p6 b/challenge-017/joelle-maslak/perl6/ch-1.p6
index 236e54db22..b289b13088 100755
--- a/challenge-017/joelle-maslak/perl6/ch-1.p6
+++ b/challenge-017/joelle-maslak/perl6/ch-1.p6
@@ -36,5 +36,5 @@ multi sub A(UInt:D $m,             UInt:D $n --> UInt:D) { A( $m-1, A($m, $n-1)
 multi sub up-arrow(UInt:D $m, UInt:D $num-arrows, 0         --> UInt:D) { 1 }
 multi sub up-arrow(UInt:D $m, 1,                  UInt:D $n --> UInt:D) { $m ** $n }
 multi sub up-arrow(UInt:D $m, UInt:D $num-arrows, UInt:D $n --> UInt:D) {
-    up-arrow($m, $num-arrows-1, up-arrow($m, $num-arrows, $n-1));
+    return up-arrow($m, $num-arrows-1, up-arrow($m, $num-arrows, $n-1));
 }
-- 
cgit