Figure 3: DTD-diagram for AREF
Child elements
none
parent elements
<
ablock
>
<
catalog
>
Attributes for AREF
Name
Type
Class
Value
Remark
[
CLASS
]
name
implied
This is the class of the referenced
<
ablock
>
.
[
IDREF
]
idref
implied
This identifies the related
<
ablock
>
by its
[
id
]
.
[
SEQUENCE
]
cdata
implied
This can take a sequence number which is used to express configurations where the sequence of elements is relevant (e.g. for documentation-fragments)
[
VIEW
]
nmtokens
implied
This allows to conditionalize the usage of the referenced ablock. As an example this could be used to distinguish different figures with respect to the intended audience (as it is done by
ASCET
).
This refers to another object (
<
ablock
>
). The reference can be done on two differents mechanisms:
[
idref
]
pointing to an
<
ablock
>
identified by
<
id
>
.
[
class
]
in conjunction with the content of ablock pointing to an
<
ablock
>
identified by
[
class
]
and
[
name
]
.
It is not intended to use both mechanisms simultaneously. If however both methods are used at the same time, they must both point to the same object. A reader must flag contradictions as an error, and may continue using ID/IDREF.
The ID based mechanism is there to support exchange of multiple versions of the same object.