DSSSL includes two independent languages, the transformation language and the style language, which specify processing of an SGML document. A DSSSL specification contains a number of process specifications, each of which uses either the style language or the transformation language. A process specification that uses the style language is a style-specification. A process specification that uses the transformation language is a transformation-specification.
If a style-specification complies with all the provisions of this International Standard, it is a conforming DSSSL style-specification. If a transformation-specification complies with all the provisions of this International Standard, it is a conforming DSSSL transformation-specification.
In both the style language and transformation language, some facilities are optional. Each optional facility is associated with a named feature. A process specification that makes use of an optional facility shall enable the feature with which it is associated using the features element type form.
A conforming DSSSL system shall support the style language, the transformation language, or both the style language and the transformation language.
The documentation for a conforming DSSSL system shall state whether it supports the transformation language or the style language or both and, for each language that the system supports, shall state which features of the language it supports.
A conforming DSSSL system that supports the style language shall be able to process any conforming SGML document using any conforming DSSSL style-specification that enables only features of the style language that the DSSSL system is documented to support.
A conforming DSSSL system that supports the transformation language shall be able to process any conforming SGML document using any conforming DSSSL transformation-specification that enables only features of the transformation language that the DSSSL system is documented to support.