Non-Property types all have a similar structure for their own element and its slot sub-elements. Let us look first at the main element and its attributes:

<graph
  description="A WatchApplication diagram defines the state automaton that implements a logical watch or a watch application."
  id="Graph_ClockApplication_sysadmin_3150525787"
  type="Graph_ClockApplication_sysadmin_3150525787"
  typeName="WatchApplication">

The description attribute contains the text from the Description field of the Graph Tool etc. The id attribute is used when referring to this type elsewhere in the XML file: it need only be unique. The type and typeName attributes are used to name the type, and to recognize it as matching an existing type, so the XML import will update that type.

A type in an XML file is recognized as matching an existing type of the same meta-type if either of the following is true: the type attribute exactly matches the internal name of the existing type, or the typeName attribute matches the user-visible name of the existing type. The GOPPRR meta-type names, e.g. Object, may not be used as values for either attribute.

In general, we expect the type attribute to be used only for files exported from MetaEdit+. As internal type names are unique, they are also used as the value of the id attribute when exporting from MetaEdit+. For files created in other programs, simply supply the typeName attribute, and any unique string for the id attribute.

Each property in a type is represented with a slot element providing information about that slot, and containing a property sub-element with the definition of the property type (or an href reference to it).

<slot
  id="a0hedn"
  name="Application name"
  unique="false">
    <property ...> ...
    </property>
</slot>

The slot id is the internal name of the slot: it can be composed of letters and numbers, but must begin with a letter. If omitted, MetaEdit+ will create naïve names p1, p2 etc., but if imported types are edited and re-imported, there is a possibility that the naïve name will clash with an earlier name. The name attribute is the local name of that property in this type, and unique specifies whether values of the property must be unique over all instances of this type (checked only when manually creating new instances).