PTOLEMY II - CiteSeerX

MoML
This element is ignored by the parser, in that it does not define a new container for the enclosed entities.
It simply aggregates them, leaving the context the same as it is for the group element itself.
The group element may be given a name attribute, in which case it defines a namespace. All
named objects (such as entities) that are immediately inside the group will have their names modified
by prepending them with the name of the group and a colon. For example,
The entity “b” will actually be named “a:b”. The entity “c” will not be affected by the group name. Its
full name, however, will be “a:b.c”.
If the namespace given is “auto” then the group tag has a particular special effect. Each element
contained immediately within the group that has a name will be assigned a new unique name within
the container based on the specified name. Hence, if the specified name is “foo”, but the container
already contains an object named “foo”, then a new object will be created with name “foo2” or “foo3”.
This feature of the group element seems rather bizarre, but it proves convenient when using MoML to
cut and paste. In order to paste a group of objects into a container, those objects have to be assigned
names that do not collide with names of objects already in the container. The following MoML will
have that effect:
In this example, automatic naming is only applied to objects immediately contained by the group.
Thus, the entity with name “b” may in fact be created with name “b2” (if there is already a “b”), but the
entity with name “c” will have name “c”.
7.5 Parsing MoML
MoML is intended to be a generic modeling markup language, not one that is specialized to
Ptolemy II. As such, Ptolemy II may be viewed as a reference implementation of a MoML tool. In
Ptolemy II, MoML is supported primarily by the moml package.
The moml package contains the classes shown in figure 7.9 (see appendix A of chapter 1 for UML
syntax). The basis for the MoML parser is the parser distributed by Microstar. The parse() methods of
the MoMLParser class read MoML data and construct a Ptolemy II model. They return the top-level
model. The same parser can then be used to incrementally parse MoML segments to modify that
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