@Section
@Title { Conclusion }
@Begin
@PP
Since its public release in October 1991, the Basser Lout interpreter
has been ported without incident to a wide variety of Unix systems and
hardware. It was tested extensively before release on its own
documentation, and the few minor bugs which have emerged since then have
all been fixed in the second release, scheduled to appear in mid-1992.
@PP
Seven substantial packages of definitions are distributed with Basser
Lout. The DocumentLayout package, and its variants ReportLayout and
BookLayout, provide the standard features that all documents
require: pages, columns, paragraphs, headings, footnotes, floating
figures and tables, chapters and sections, displays and lists, access
to bibliographic databases, cross references, and so on
[11]. The BookLayout package has extra features
needed by books, including an automatically generated table of contents,
Roman page numbers for the prefatory material, running page headers,
odd and even page layouts, and a sorted index. The Eq package formats
equations, and Pas formats Pascal programs [10]; Tab
formats tables [12]; and Fig draws figures
[6].
@PP
The non-expert user who uses these packages perceives a system of a
standard quite similar to other fully developed batch formatters,
although the interface is considerably more coherent than, say, the troff
family's [8]. The expert user perceives a system which
is radically different from previous ones, in which a great deal can be
achieved very quickly. To take an extreme example, Pas was designed,
implemented, tested, and documented in one afternoon. Eq took about
a week, but most of that time was spent in marshalling the vast
repertoire of mathematical symbols, and fine-tuning the spacing. Most
of the effort seems to go into designing a good interface; most symbols
are implemented in just one or a few lines of Lout.
@PP
A group of about 20 satisfied non-expert users has grown up within
the author's department, mainly Honours students with no investment
in older systems to hold them back. Basser Lout has been advertised
on the Internet news as available via anonymous {@I ftp}, so the
extent of its outside user community is hard to gauge. About 50
people have mailed comments or questions to the author; many
of these people have ported the program, written small definitions,
and modified the standard packages.
@PP
Future work could usefully begin with the improvements suggested in this
paper: overlapping spanning columns, better semantics for available
space, and especially horizontal galleys. Support for non-European
languages is also needed. However, the main task is the development of
an interactive document editor based on Lout. A structure editor similar
to Lilac [13], which already has objects and user-defined
symbols, is envisaged; since cross references are easy when the whole
document is available, the only major new problem is the treatment of
galleys, including the expansion and retraction of receptive symbols.
@LP
@LP
@B { Note. } Since the above was written the author has completed a
revised version of Basser Lout, in which the problem concerning
available space mentioned in Section {@NumberOf style} has been resolved.
@LP
@LP
@B { Acknowledgment. } The author gratefully acknowledges many
valuable discussions with Douglas W. Jones, especially during the
development of the galley abstraction; and also many helpful comments on
presentation by the anonymous referee.
@DP
@DP
@Heading { References }
@NumberedList
@LI @RefPrint kingston91
@LI @RefPrint kingston91over
@LI @RefPrint kingston91basser
@LI @RefPrint furuta82
@LI @RefPrint kernighan75
@LI @RefPrint kingston91fig
@LI @RefPrint reid80
@LI @RefPrint ossanna76
@LI @RefPrint knuth84
@LI @RefPrint kingston91eq
@LI @RefPrint kingston91begin
@LI @RefPrint kingston91tab
@LI @RefPrint brooks91
@EndList
@End @Section
