Jade does not support the DSSSL Transformation Language. However, it
provides some simple, non-standardized extensions to the DSSSL Style
Language that allow it to be used for SGML transformations.
These extensions are used in conjunction with the SGML backend which
is selected with the -t sgml or -t xml options.
Unlike other backends,
the SGML backend writes its output to the standard output.
The -t xml option makes empty elements and processing
instructions use the XML syntax. Note that the XML declaration is not
automatically emitted.
The extensions consist of a collection of flow object classes that are used
instead of the standard DSSSL-defined flow object classes:
element
empty-element
Each of these flow objects results in an element in the output. The
element flow object is a compound flow object (one that
can have child flow objects). Both a start-tag and an end-tag are
generated for this flow object. The empty-element is an
atomic flow object (one that cannot have child flow objects). Only a
start-tag is output for this. It should should be used for elements
with a declared content of EMPTY or with a content reference
attribute.
Both of these flow objects support the following non-inherited
characteristics:
gi
This is a string-valued characteristic that specifies the element's
generic identifier.
It defaults to the generic identifier of the current node.
attributes
This specifies the element's attributes as a list of lists each of
which consists of exactly two strings, the first specifying the
attribute name and the second the attribute value.
It defaults to the empty list.
processing-instruction
This is an atomic flow object that results in a processing instruction.
It supports the following non-inherited characteristics:
data
This is a string-valued characteristic that specifies the content
of the processing instruction.
It defaults to the empty string.
document-type
This is an atomic flow object that results in a DOCTYPE declaration.
It supports the following non-inherited characteristics:
name
This is a string-valued characteristic that specifies the name
of the document type (which must be the same as the name of
the document element).
It must not be omitted.
system-id
This is a string-valued characteristic that specifies the system identifier
of the document type.
If non-empty, this will be used as the system identifier in the
doctype declaration.
The default value is the empty string.
public-id
This is a string-valued characteristic that specifies the public identifier
of the document type.
If non-empty, this will be used as the public identifier in the
doctype declaration.
The default value is the empty string.
entity
This is an compound flow object that stores its content in a separate
entity. It supports the following non-inherited characteristic:
system-id
The system identifier of the entity.
For now this is treated as a filename not as an FSI.
Note that no entity reference or declaration is emitted.
entity-ref
This is an atomic flow object that results in an entity reference.
It supports the following non-inherited characteristic:
name
The name of the entity.
formatting-instruction
This is an atomic flow object that inserts characters into the output
without change.
It supports the following non-inherited characteristic:
data
This is the string to be inserted.
It differs from normal data characters in the &,
< and > will not be escaped.
There is also the following characteristic:
preserve-sdata?
This is an inherited boolean characteristic that applies to character
flow objects. When true, if the current-node for the character flow object
was an sdata node, then the character will be output as a reference
to an entity with the same name.
The initial value is #f.
Each of these flow object classes must be declared using
declare-flow-object-class in any DSSSL specification that
makes use of it.
A suitable set of declarations is: