Re: Viewer Engine

From: John J. Deneen (
Date: Sun Aug 06 2000 - 16:10:57 PDT

> One of the up-front requirements is that the viewing engine will support
> all kinds of output, although the system that we build will initially
> support HTML w/ JavaScript (or as Joe says, XHTML with ECMAScript).


The Extensible Markup Language(XML) was designed to be a simplified
version of SGML for the Internet, and is growing in popularity. SHOE was
originally designed to be embedded in HTML pages, but since it uses an
SGML syntax it can be used within XML documents with only a minimum of
modifications. The XML version of the SHOE DTD can be found at Before you can
include the XML version of SHOE in a document, you must make sure that
the document is XML compliant. If it is an HTML document, then you make
the document compliant with the W3C's recommendation on XHTML 1.0: The
Extensible HyperText Markup Language. Then to include SHOE in the XHTML
markup, simply follow the guidelines set forth in the W3C's Namespaces
in XML Recommendation. Essentially, this means insert the following at
the desired location in the document:

<shoe xmlns="" version="1.0">

and include the desired ONTOLOGY or INSTANCE tags between this tag and a
</shoe> tag.

Due to the differences in between SGML and XML, SHOE XML is more
restrictive and requires a slight variant in syntax than that described
in the main section of this document.

All empty elements, i.e., elements which have no content and no end tag,
must end with a '/>' instead of a '>'. Specifically, this applies to the
CATEGORY, and ARG elements.

No attribute minimization is allowed. Therefore, when specifying VAR or
CONST within the categories or arguments in an inference rule, the
attribute name USAGE must be explicitly provided, e.g. USAGE="VAR"
instead of VAR. Since XML is case-sensitive, all element and attribute
names must be in lower case. All attribute values must always be quoted,
including those which are numeric as well as the "FROM" and "TO"

SHOE can also be used independently of XHTML. A non-embedded SHOE XML
document must begin with the appropriate XML prolog:

<?xml version="1.0"?>

This archive was generated by hypermail 2.0.0 : Tue Aug 21 2001 - 17:57:49 PDT