diff --git a/lib/puppet/parser/functions/validate_slength.rb b/lib/puppet/parser/functions/validate_slength.rb
new file mode 100644
index 0000000..fdcc0a2
--- /dev/null
+++ b/lib/puppet/parser/functions/validate_slength.rb
@@ -0,0 +1,52 @@
+module Puppet::Parser::Functions
+
+  newfunction(:validate_slength, :doc => <<-'ENDHEREDOC') do |args|
+    Validate that the first argument is a string (or an array of strings), and
+    less/equal to than the length of the second argument.  It fails if the first
+    argument is not a string or array of strings, and if arg 2 is not convertable
+    to a number.
+
+    The following values will pass:
+
+      validate_slength("discombobulate",17)
+      validate_slength(["discombobulate","moo"],17)
+
+    The following valueis will not:
+
+      validate_slength("discombobulate",1)
+      validate_slength(["discombobulate","thermometer"],5)
+
+    ENDHEREDOC
+
+    raise Puppet::ParseError, ("validate_slength(): Wrong number of arguments (#{args.length}; must be = 2)") unless args.length == 2
+
+    unless (args[0].is_a?(String) or args[0].is_a?(Array))
+      raise Puppet::ParseError, ("validate_slength(): please pass a string, or an array of strings - what you passed didn't work for me at all - #{args[0].class}")
+    end
+
+    begin
+      max_length = args[1].to_i
+    rescue NoMethodError => e
+      raise Puppet::ParseError, ("validate_slength(): Couldn't convert whatever you passed as the length parameter to an integer  - sorry: " + e.message )
+    end
+
+    raise Puppet::ParseError, ("validate_slength(): please pass a positive number as max_length") unless max_length > 0
+
+    case args[0]
+      when String
+        raise Puppet::ParseError, ("validate_slength(): #{args[0].inspect} is #{args[0].length} characters.  It should have been less than or equal to #{max_length} characters") unless args[0].length <= max_length
+      when Array
+        args[0].each do |arg|
+          if arg.is_a?(String)
+            unless ( arg.is_a?(String) and arg.length <= max_length )
+              raise Puppet::ParseError, ("validate_slength(): #{arg.inspect} is #{arg.length} characters.  It should have been less than or equal to #{max_length} characters")
+            end
+          else
+            raise Puppet::ParseError, ("validate_slength(): #{arg.inspect} is not a string, it's a #{arg.class}")
+          end
+        end
+      else
+        raise Puppet::ParseError, ("validate_slength(): please pass a string, or an array of strings - what you passed didn't work for me at all - #{args[0].class}")
+    end
+  end
+end
diff --git a/spec/unit/puppet/parser/functions/validate_slength_spec.rb b/spec/unit/puppet/parser/functions/validate_slength_spec.rb
new file mode 100755
index 0000000..d2d4ca0
--- /dev/null
+++ b/spec/unit/puppet/parser/functions/validate_slength_spec.rb
@@ -0,0 +1,52 @@
+#!/usr/bin/env rspec
+
+require 'spec_helper'
+
+describe "the validate_slength function" do
+  before :all do
+    Puppet::Parser::Functions.autoloader.loadall
+  end
+
+  let(:scope) { Puppet::Parser::Scope.new }
+
+  it "should exist" do
+    Puppet::Parser::Functions.function("validate_slength").should == "function_validate_slength"
+  end
+
+  it "should raise a ParseError if there is less than 2 arguments" do
+    expect { scope.function_validate_slength([]) }.to(raise_error(Puppet::ParseError))
+    expect { scope.function_validate_slength(["asdf"]) }.to(raise_error(Puppet::ParseError))
+  end
+
+  it "should raise a ParseError if argument 2 doesn't convert to a fixnum" do
+    expect { scope.function_validate_slength(["moo",["2"]]) }.to(raise_error(Puppet::ParseError, /Couldn't convert whatever you passed/))
+  end
+
+  it "should raise a ParseError if argument 2 converted, but to 0, e.g. a string" do
+    expect { scope.function_validate_slength(["moo","monkey"]) }.to(raise_error(Puppet::ParseError, /please pass a positive number as max_length/))
+  end
+
+  it "should raise a ParseError if argument 2 converted, but to 0" do
+    expect { scope.function_validate_slength(["moo","0"]) }.to(raise_error(Puppet::ParseError, /please pass a positive number as max_length/))
+  end
+
+  it "should fail if string greater then size" do
+    expect { scope.function_validate_slength(["test", 2]) }.to(raise_error(Puppet::ParseError, /It should have been less than or equal to/))
+  end
+
+  it "should fail if you pass an array of something other than strings" do
+    expect { scope.function_validate_slength([["moo",["moo"],Hash.new["moo" => 7]], 7]) }.to(raise_error(Puppet::ParseError, /is not a string, it's a/))
+  end
+
+  it "should fail if you pass something other than a string or array" do
+    expect { scope.function_validate_slength([Hash.new["moo" => "7"],6]) }.to(raise_error(Puppet::ParseError), /please pass a string, or an array of strings/)
+  end
+
+  it "should not fail if string is smaller or equal to size" do
+    expect { scope.function_validate_slength(["test", 5]) }.to_not(raise_error(Puppet::ParseError))
+  end
+
+  it "should not fail if array of string is are all smaller or equal to size" do
+    expect { scope.function_validate_slength([["moo","foo","bar"], 5]) }.to_not(raise_error(Puppet::ParseError))
+  end
+end