diff --git a/lib/puppet/parser/functions/defined_with_params.rb b/lib/puppet/parser/functions/defined_with_params.rb
new file mode 100644
index 0000000..e09e41c
--- /dev/null
+++ b/lib/puppet/parser/functions/defined_with_params.rb
@@ -0,0 +1,33 @@
+# Test whether a given class or definition is defined
+require 'puppet/parser/functions'
+
+Puppet::Parser::Functions.newfunction(:defined_with_params,
+                                      :type => :rvalue,
+                                      :doc => <<-'ENDOFDOC'
+Takes a resource reference and an optional hash of attributes.
+
+Returns true if a resource with the specified attributes has already been added
+to the catalog, and false otherwise.
+
+    user { 'dan':
+      ensure => present,
+    }
+
+    if ! defined_with_params(User[dan], {'ensure' => 'present' }) {
+      user { 'dan': ensure => present, }
+    }
+ENDOFDOC
+) do |vals|
+  reference, params = vals
+  raise(ArgumentError, 'Must specify a reference') unless reference
+  params ||= {}
+  ret = false
+  if resource = findresource(reference.to_s)
+    matches = params.collect do |key, value|
+      resource[key] == value
+    end
+    ret = params.empty? || !matches.include?(false)
+  end
+  Puppet.debug("Resource #{reference} was not determined to be defined")
+  ret
+end
diff --git a/lib/puppet/parser/functions/ensure_resource.rb b/lib/puppet/parser/functions/ensure_resource.rb
new file mode 100644
index 0000000..8f9eadf
--- /dev/null
+++ b/lib/puppet/parser/functions/ensure_resource.rb
@@ -0,0 +1,28 @@
+# Test whether a given class or definition is defined
+require 'puppet/parser/functions'
+
+Puppet::Parser::Functions.newfunction(:ensure_resource,
+                                      :type => :statement,
+                                      :doc => <<-'ENDOFDOC'
+Takes a resource type, title, and a list of attributes that describe a
+resource.
+
+    user { 'dan':
+      ensure => present,
+    }
+
+This example only creates the resource if it does not already exist:
+
+    ensure_resource('user, 'dan', {'ensure' => 'present' })
+ENDOFDOC
+) do |vals|
+  type, title, params = vals
+  raise(ArgumentError, 'Must specify a type') unless type
+  raise(ArgumentError, 'Must specify a title') unless title
+  params ||= {}
+  if function_defined_with_params(["#{type}[#{title}]", params])
+    Puppet.debug("Resource #{type}[#{title}] does not need to be created b/c it already exists")
+  else
+    function_create_resources([type.capitalize, { title => params }])
+  end
+end
diff --git a/spec/functions/defined_with_params_spec.rb b/spec/functions/defined_with_params_spec.rb
new file mode 100644
index 0000000..21c08a0
--- /dev/null
+++ b/spec/functions/defined_with_params_spec.rb
@@ -0,0 +1,31 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper'
+
+require 'rspec-puppet'
+describe 'defined_with_params' do
+  describe 'when a resource is not specified' do
+    it { should run.with_params().and_raise_error(ArgumentError) }
+  end
+  describe 'when compared against a resource with no attributes' do
+    let :pre_condition do
+      'user { "dan": }'
+    end
+    it do
+      should run.with_params('User[dan]', {}).and_return(true)
+      should run.with_params('User[bob]', {}).and_return(false)
+      should run.with_params('User[dan]', {'foo' => 'bar'}).and_return(false)
+    end
+  end
+
+  describe 'when comparted against a resource with attributes' do
+    let :pre_condition do
+      'user { "dan": ensure => present, shell => "/bin/csh", managehome => false}'
+    end
+    it do
+      should run.with_params('User[dan]', {}).and_return(true)
+      should run.with_params('User[dan]', {'ensure' => 'present'}).and_return(true)
+      should run.with_params('User[dan]', {'ensure' => 'present', 'managehome' => false}).and_return(true)
+      should run.with_params('User[dan]', {'ensure' => 'absent', 'managehome' => false}).and_return(false)
+    end
+  end
+end
diff --git a/spec/functions/ensure_resource_spec.rb b/spec/functions/ensure_resource_spec.rb
new file mode 100644
index 0000000..e45a6d0
--- /dev/null
+++ b/spec/functions/ensure_resource_spec.rb
@@ -0,0 +1,35 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper'
+
+require 'rspec-puppet'
+describe 'ensure_resource' do
+  describe 'when a type or title is not specified' do
+    it do
+      should run.with_params().and_raise_error(ArgumentError)
+      should run.with_params(['type']).and_raise_error(ArgumentError)
+    end
+  end
+  describe 'when compared against a resource with no attributes' do
+    let :pre_condition do
+      'user { "dan": }'
+    end
+    it do
+      should run.with_params('user', 'dan', {})
+      compiler.catalog.resource('User[dan]').to_s.should == 'User[dan]'
+    end
+  end
+
+  describe 'when comparted against a resource with attributes' do
+    let :pre_condition do
+      'user { "dan": ensure => present, shell => "/bin/csh", managehome => false}'
+    end
+    it do
+      # these first three should not fail
+      should run.with_params('User', 'dan', {})
+      should run.with_params('User', 'dan', {'ensure' => 'present'})
+      should run.with_params('User', 'dan', {'ensure' => 'present', 'managehome' => false})
+      #  test that this fails
+      should run.with_params('User', 'dan', {'ensure' => 'absent', 'managehome' => false}).and_raise_error(Puppet::Error)
+    end
+  end
+end