Addition of new length function

README.markdown

@@ -815,6 +815,10 @@ The return value is an array in which each element is one joined key/value pair.
 
 Returns the keys of a hash as an array. *Type*: rvalue.
 
+#### `length`
+
+Returns the length of a given string, array or hash. To eventually replace the deprecated size() function as can handle the new type functionality introduced in Puppet 4. *Type*: rvalue.
+
 #### `loadyaml`
 
 Loads a YAML file containing an array, string, or hash, and returns the data in the corresponding native data type.
@@ -1067,7 +1071,7 @@ Randomizes the order of a string or array elements. *Type*: rvalue.
 
 #### `size`
 
-Returns the number of elements in a string, an array or a hash. *Type*: rvalue.
+Returns the number of elements in a string, an array or a hash. May get confused around Puppet 4 type values and as such is to be deprecated in the next release and replaced with the new stdlib length function. *Type*: rvalue.
 
 #### `sort`
 

lib/puppet/functions/length.rb

@@ -0,0 +1,14 @@
+#A function to eventually replace the old size() function for stdlib - The original size function did not handle Puppets new type capabilities, so this function is a Puppet 4 compatible solution. 
+Puppet::Functions.create_function(:length) do
+  dispatch :length do
+    param 'Variant[String,Array,Hash]', :value
+  end
+  def	length(value)
+    if value.is_a?(String)
+      result = value.length
+    elsif value.is_a?(Array) || value.is_a?(Hash)
+      result = value.size
+    end
+    return result
+  end
+end

lib/puppet/parser/functions/size.rb

@@ -13,6 +13,8 @@ module Puppet::Parser::Functions
 
     item = arguments[0]
 
+    function_deprecation([:size, 'This method is going to be deprecated, please use the stdlib length function.'])
+
     if item.is_a?(String)
 
       begin

spec/functions/length.rb

@@ -0,0 +1,35 @@
+require 'spec_helper'
+
+describe 'length' do
+  it { is_expected.not_to eq(nil) }
+  it { is_expected.to run.with_params().and_raise_error(ArgumentError, /'length' expects 1 argument, got none/) }
+  it { is_expected.to run.with_params([], 'extra').and_raise_error(ArgumentError, /'length' expects 1 argument, got 2/) }
+  it { is_expected.to run.with_params(1).and_raise_error(ArgumentError, /expects a value of type String, Array, or Hash, got Integer/) }
+  it { is_expected.to run.with_params(true).and_raise_error(ArgumentError, /expects a value of type String, Array, or Hash, got Boolean/) }
+  it { is_expected.to run.with_params('1').and_return(1) }
+  it { is_expected.to run.with_params('1.0').and_return(3) }
+  it { is_expected.to run.with_params([]).and_return(0) }
+  it { is_expected.to run.with_params(['a']).and_return(1) }
+  it { is_expected.to run.with_params(['one', 'two', 'three']).and_return(3) }
+  it { is_expected.to run.with_params(['one', 'two', 'three', 'four']).and_return(4) }
+
+  it { is_expected.to run.with_params({}).and_return(0) }
+  it { is_expected.to run.with_params({'1' => '2'}).and_return(1) }
+  it { is_expected.to run.with_params({'1' => '2', '4' => '4'}).and_return(2) }
+  it { is_expected.to run.with_params({'€' => '@', '竹' => 'ǿňè'}).and_return(2) }
+
+  it { is_expected.to run.with_params('').and_return(0) }
+  it { is_expected.to run.with_params('a').and_return(1) }
+  it { is_expected.to run.with_params('abc').and_return(3) }
+  it { is_expected.to run.with_params('abcd').and_return(4) }
+  it { is_expected.to run.with_params('万').and_return(1) }
+  it { is_expected.to run.with_params('āβćđ').and_return(4) }
+
+  context 'when using a class extending String' do
+    it 'should call its size method' do
+      value = AlsoString.new('asdfghjkl')
+      value.expects(:length).returns('foo')
+      expect(subject).to run.with_params(value).and_return('foo')
+    end
+  end
+end