Canonical Documents
A canonical XML document defines the standard manner in which
to represent a commonly used piece of information.
Boolean
A canonical Boolean document is used to represent a boolean state of true or false.
It
is expected as the target in a conditional instruction for both
if
and
while
DPML statements.
It contains a root element of
<b>
with a text value of
t
or
f.
Exception
If an error occurs and exception is raised it will be associated with a resource
describing the problem.
This resource has the identity
this:exception
and is available to instructions in an exception handling block.
The exception resource is an XML fragment with the root element
<ex>
and may contain child
<ex>
elements.
The outer <ex> frame is
the deepest cause of the problem and nested frame more distant effects.
Inside each exception there are the following elements:
| Element |
|
| id |
An identifier for the problem.
|
| message |
A descriptive message describing the problem.
|
| callstack |
If available, a Java callstack pointing to the line of code where the error occurred.
|
The exception handling block may wish to use the xpatheval instruction to detect certain exceptions
and provide specific handling.
<ex>
<id>CANCELED_EVENT</id>
<message>No horses</message>
<callstack>??</callstack>
<ex>
<id>BROKEN_LEG</id>
<message>Fell going over a jump</message>
<callstack>??</callstack>
</ex>
</ex>
URI
A canonical URI document is used to represent a single URI reference. It is used
in the
curi
data type. It contains a root element of
<uri>
and a text
value of a syntactically correct URI.
<uri>http://www.1060.org/index.html</uri>
XPath
A canonical XPath document is used to represent a single XPath statement. It is used
in the
xpatheval
instruction. It contains a root element of
<xpath>
and a
text value of a syntactically correct XPath.
Preface
XML Resource Model
XRL
