add a "step" argument to range()

This patch adds an optional "step" argument to the stdlib range()
function.  There is no change to the default behavior of the function;
however, passing a numeric "step" argument invokes the Ruby Range#step
method, e.g.

    range("0", "9", "2")

returns

    [0,2,4,6,8]

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/puppet/parser/functions/range.rb b/lib/puppet/parser/functions/range.rb
index 6e85422..03ab9e9 100644
--- a/lib/puppet/parser/functions/range.rb
+++ b/lib/puppet/parser/functions/range.rb
@@ -18,6 +18,13 @@ Will return: [0,1,2,3,4,5,6,7,8,9]
     range("a", "c")
 
 Will return: ["a","b","c"]
+
+Passing a third argument will cause the generated range to step by that 
+interval, e.g.
+
+    range("0", "9", "2")
+
+Will return: [0,2,4,6,8]
     EOS
   ) do |arguments|
 
@@ -28,6 +35,7 @@ Will return: ["a","b","c"]
     if arguments.size > 1
       start = arguments[0]
       stop  = arguments[1]
+      step  = arguments[2].nil? ? 1 : arguments[2].to_i.abs
 
       type = '..' # We select simplest type for Range available in Ruby ...
 
@@ -62,7 +70,7 @@ Will return: ["a","b","c"]
         when /^(\.\.\.)$/  then (start ... stop) # Exclusive of last element ...
       end
 
-      result = range.collect { |i| i } # Get them all ... Pokemon ...
+      result = range.step(step).collect { |i| i } # Get them all ... Pokemon ...
 
     return result
   end