Section 2.2: Authoring and Editing tools
Authoring and editing tools form the largest single group of
SGML-aware products. ISO Technical Report 10037 Guidelines for
SGML Syntax-Directed Editing Systems (see Annex A) has been
written specifically to assist prospective purchasers of
authoring software, and the authors of this report would
recommend this TR as a useful background document (see Annex A).
This section is further divided into two sub-sections covering
(A) specific SGML document editors, and (B) SGML-aware `add-ons'
to existing word-processing packages and page-composition
systems. All the early products were developed specifically as
SGML-aware editors. They would only edit SGML documents. These
dedicated systems are intended to be able to handle any DTD (some
are better than others!) and any of the features of SGML (for
example, Marked Sections and Shortrefs) which make it so
powerful. As SGML has become important in more and more
industries and has been seen to be expanding into more general
areas of document production than was originally expected, some
of the major word-processor and publishing products have added or
are adding SGML-aware facilities on to their existing products.
These products have the benefit of being extensively used in the
general word-processing or publishing markets and so may have
more highly developed user interfaces and user facilities, but
lack the full awareness and requirements of true SGML systems.
This is because without exception they convert the
SGML into their own internal format, and, on export, are unable
to retain (or regain) the full set of SGML features used in the
original document.
In addition to the decision about SGML-specific or SGML-
conversion, organisations must consider a range of other points
when deciding which editor / authoring system to use. These are:
- To what extent may the SGML declaration be examined, or
edited? May the user supply their own SGML declaration, and
so vary the SGML syntax and character sets used? [Note:
This will become more significant as systems become
available that allow 7, 8 and 32-bit characters based on
ISO 10646 / Unicode to be used.]
- Are there sample DTDs supplied, and how easy is it for the
users to use their own DTDs?
- How easy is it to include entity sets, and are sample
entity sets supplied or incorporated into the product?
- What optional features are provided? Some `optional'
features would be considered essential in all editors.
However, many organisations believe that they will not
require some of the optional features initially, but when
fully converted to using SGML find that they do require
them.
- Does the system assist in the preparation of the SGML
Declaration?, and of the DTDs? And the related question,
are DTDs `compiled' and stored in a binary form?, so
speeding up the initialisation of a new document and also
ensuring that authors do not amend the DTD.
- How are the documents stored as SGML files, or in some
internal format? If stored in an internal format, what (if
any) loss of information is there when converting?, and can
all legal SGML constructs be handled both when reading in
and when writing out?
- Can the editor display in a variety of forms with the
tags hidden, with the tags displayed but not editable, with
the tags and attributes displayed and editable? The related
questions, to what extent does the editor allow the user to
control the layout on screen?, and (if printing is
available) on the printer?
- Are filters provided to convert from other (non-SGML) word-
processing and authoring products?
- How are graphics handled? Can they be displayed in-line, or
just referenced?
- Finally, how is the validation of the created or edited
document done? It may be dynamically validated as the
document is created, by a specific user-action during or at
the end of editing, or by the calling of a separate
validation process (a `parser') on the created file.