1 files changed, 27 insertions, 0 deletions
diff --git a/lib/puppet/parser/functions/defined.rb b/lib/puppet/parser/functions/defined.rb
new file mode 100644
index 000000000..4e369ae48
--- /dev/null
+++ b/lib/puppet/parser/functions/defined.rb
@@ -0,0 +1,27 @@
+# Test whether a given class or definition is defined
+Puppet::Parser::Functions::newfunction(:defined, :type => :rvalue, :doc => "Determine whether a given
+    type is defined, either as a native type or a defined type, or whether a class is defined.
+    This is useful for checking whether a class is defined and only including it if it is.
+    This function can also test whether a resource has been defined, using resource references
+    (e.g., ``if defined(File['/tmp/myfile']) { ... }``).  This function is unfortunately
+    dependent on the parse order of the configuration when testing whether a resource is defined.") do |vals|
+        result = false
+        vals.each do |val|
+            case val
+            when String:
+                # For some reason, it doesn't want me to return from here.
+                if Puppet::Type.type(val) or finddefine(val) or findclass(val)
+                    result = true
+                    break
+                end
+            when Puppet::Parser::Resource::Reference:
+                if findresource(val.to_s)
+                    result = true
+                    break
+                end
+            else
+                raise ArgumentError, "Invalid argument of type %s to 'defined'" % val.class
+            end
+        end
+        result
+end