5 files changed, 117 insertions, 0 deletions
diff --git a/challenge-171/arne-sommer/blog.txt b/challenge-171/arne-sommer/blog.txt
new file mode 100644
index 0000000000..ad24babe59
--- /dev/null
+++ b/challenge-171/arne-sommer/blog.txt
@@ -0,0 +1 @@
+https://raku-musings.com/abundantly-first-class.html
diff --git a/challenge-171/arne-sommer/raku/abundant-number b/challenge-171/arne-sommer/raku/abundant-number
new file mode 100755
index 0000000000..b7e8b2c4e7
--- /dev/null
+++ b/challenge-171/arne-sommer/raku/abundant-number
@@ -0,0 +1,27 @@
+#! /usr/bin/env raku
+
+unit sub MAIN (Int :c(:$count) where $count > 0 = 20, :v(:$verbose));
+
+my $abundant := (1 .. Inf).grep( *.&is-abundant );
+
+say $abundant[^$count].join(", ");
+
+sub divisors ($number, :$not-self, :$not-one)
+{
+  my @divisors;
+  
+  for ($not-one ?? 2 !! 1) .. $number/2 -> $candidate
+  {
+    @divisors.push: $candidate if $number %% $candidate;
+  }
+  
+  @divisors.push: $number unless $not-self;
+  say ": $number -> @divisors[] = { @divisors.sum }" if $verbose;  
+  return @divisors;
+}
+
+sub is-abundant ($number)
+{
+  return $number % 2 && divisors($number, :not-self).sum > $number;
+  # return $number % 2 && divisors($number).sum > $number * 2;
+}
diff --git a/challenge-171/arne-sommer/raku/ch-1.raku b/challenge-171/arne-sommer/raku/ch-1.raku
new file mode 100755
index 0000000000..b7e8b2c4e7
--- /dev/null
+++ b/challenge-171/arne-sommer/raku/ch-1.raku
@@ -0,0 +1,27 @@
+#! /usr/bin/env raku
+
+unit sub MAIN (Int :c(:$count) where $count > 0 = 20, :v(:$verbose));
+
+my $abundant := (1 .. Inf).grep( *.&is-abundant );
+
+say $abundant[^$count].join(", ");
+
+sub divisors ($number, :$not-self, :$not-one)
+{
+  my @divisors;
+  
+  for ($not-one ?? 2 !! 1) .. $number/2 -> $candidate
+  {
+    @divisors.push: $candidate if $number %% $candidate;
+  }
+  
+  @divisors.push: $number unless $not-self;
+  say ": $number -> @divisors[] = { @divisors.sum }" if $verbose;  
+  return @divisors;
+}
+
+sub is-abundant ($number)
+{
+  return $number % 2 && divisors($number, :not-self).sum > $number;
+  # return $number % 2 && divisors($number).sum > $number * 2;
+}
diff --git a/challenge-171/arne-sommer/raku/ch-2.raku b/challenge-171/arne-sommer/raku/ch-2.raku
new file mode 100755
index 0000000000..1b20bfbba7
--- /dev/null
+++ b/challenge-171/arne-sommer/raku/ch-2.raku
@@ -0,0 +1,31 @@
+#! /usr/bin/env raku
+
+my $f = sub f ($val)
+{
+  return $val * 10;
+}
+
+my $g = sub g ($val)
+{
+  return $val + 1;
+}
+
+sub compose(&f, &g)
+{
+  return sub ($arg)
+  {
+    &f(&g($arg));
+  };
+}
+
+my $h = compose($f, $g);
+
+say $h(12);
+say $h(13);
+
+my $m = compose($g, $f);
+
+say $m(12);
+say $m(13);
+
+
diff --git a/challenge-171/arne-sommer/raku/first-class-function b/challenge-171/arne-sommer/raku/first-class-function
new file mode 100755
index 0000000000..1b20bfbba7
--- /dev/null
+++ b/challenge-171/arne-sommer/raku/first-class-function
@@ -0,0 +1,31 @@
+#! /usr/bin/env raku
+
+my $f = sub f ($val)
+{
+  return $val * 10;
+}
+
+my $g = sub g ($val)
+{
+  return $val + 1;
+}
+
+sub compose(&f, &g)
+{
+  return sub ($arg)
+  {
+    &f(&g($arg));
+  };
+}
+
+my $h = compose($f, $g);
+
+say $h(12);
+say $h(13);
+
+my $m = compose($g, $f);
+
+say $m(12);
+say $m(13);
+
+