1 files changed, 46 insertions, 0 deletions
diff --git a/lib/puppet/parser/functions/shuffle.rb b/lib/puppet/parser/functions/shuffle.rb
new file mode 100644
index 0000000..18134ab
--- /dev/null
+++ b/lib/puppet/parser/functions/shuffle.rb
@@ -0,0 +1,46 @@
+#
+# shuffle.rb
+#
+
+module Puppet::Parser::Functions
+  newfunction(:shuffle, :type => :rvalue, :doc => <<-EOS
+Randomizes the order of a string or array elements.
+    EOS
+  ) do |arguments|
+
+    raise(Puppet::ParseError, "shuffle(): Wrong number of arguments " +
+      "given (#{arguments.size} for 1)") if arguments.size < 1
+
+    value = arguments[0]
+    klass = value.class
+
+    unless [Array, String].include?(klass)
+      raise(Puppet::ParseError, 'shuffle(): Requires either ' +
+        'array or string to work with')
+    end
+
+    result = value.clone
+
+    string = value.is_a?(String) ? true : false
+
+    # Check whether it makes sense to shuffle ...
+    return result if result.size <= 1
+
+    # We turn any string value into an array to be able to shuffle ...
+    result = string ? result.split('') : result
+
+    elements = result.size
+
+    # Simple implementation of Fisher–Yates in-place shuffle ...
+    elements.times do |i|
+      j = rand(elements - i) + i
+      result[j], result[i] = result[i], result[j]
+    end
+
+    result = string ? result.join : result
+
+    return result
+  end
+end
+
+# vim: set ts=2 sw=2 et :