[Groff] Mission statement - final

[Peter Schaffter]

Unless anyone has quibbles with specific vocabulary, this will
be our mission statement.  It's somewhat beefed up from draft 3,
and I've incorporated the best suggestions subsequent to that
draft--particularly Doug's, who felt it wasn't mission-statement-y
enough.  I believe it reflects the consensus of the list, and puts
an attractive face on groff for the benefit of anyone wishing to
join the development team.

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                      Groff Mission Statement
                                2014

As the most widely-deployed implementation of troff in use today,
groff holds an important place in the Unix universe.  Frequently
and erroneously dismissed as a legacy program for formatting
Unix manuals (manpages), groff is in fact a sophisticated system
for producing high-quality typeset material, from business
correspondence to complex, technical reports and plate-ready books.
With an impressive record for backward compatibility, it continues
to evolve and play a leading role in the development of free
typesetting software.
  Future development will focus on groff's typesetting capabilities,
the goal being to improve automatic formatting of documents without
a corresponding loss of user control over typographic details.  In
addition to the core binary, where much of the work will be done,
the system comprises a macro language, pre-built macro sets, pre-
and post-processors, and drivers for outputting to various formats.
The guiding principle for changes to these parts will be to improve
and extend, not alter, especially with respect to established usage.
  A key part of the project's mandate will be to redress issues
that have historically discouraged widespread adoption of groff.
Issues include the perceived superiority of TeX for general-purpose
typesetting, the long and somewhat unfortunate association with
manpages, and the difficulty of mastering groff's low-level
typesetting requests.
  Broadly speaking, development will be channelled into two areas:
  - core groff
    - the typesetting backend and low-level formatting requests
  - program usage
    - general-purpose macro sets and manpages
Improvements and enhancements to other areas of the system will
continue to form a routine part of groff's growth, with active
support for contributions provided by a team of groff mavens.

CORE GROFf

The backend

  Groff currently uses a greedy algorithm to format paragraphs
one line at a time, but the Knuth-Plass algorithm, implemented in
TeX, Heirloom troff and elsewhere, optimizes linebreaks throughout
whole paragraphs and achieves a more uniform typographic grey.  One
of the most exciting challenges facing groff will be implementing
an improved formatting algorithm, the most likely candidate being
Knuth-Plass.  It's a big job, but with groff's clean codebase and
helpful community of experts, it is hoped additional developers will
step forward and contribute their programming skills.
  Equally important to the backend will be instituting native
support for TrueType, OpenType, and other non-Type1 PostScript
fonts, and improving Unicode support.

Low-level formatting requests

  Supplementary low-level formatting requests will continue to be
added, and the behaviour of some existing requests reviewed, with
care taken to maintain backward compatibility whenever modifications
are deemed worthwhile.  At the request level, groff's use of integer
arithmetic and linear evaluation of expressions hearkens back to
the stone age.  While not top-priority, these and other historical
encumbrances (read "annoyances") will be addressed--again, with a
watchful eye toward backward compatibility.

PROGRAM USAGE

General-purpose macro sets

  Macro sets form the primary user interface to groff.  Well-
designed, well-documented sets help make groff accessible to
users--new users in particular.  Adoption or rejection of the
program is often based on whether available sets meet user needs
without requiring mastery of low-level requests.  Learning curve
and ease of use are equally important.
  The most active area of groff development in the past decade has
been in macro sets, with mom alone adding over 13,000 lines of code
and 1MB of documentation to the project.  Support for existing macro
sets and the design/development of new ones will therefore play a
significant role in groff's future.

Manpages

  The need for Unix manuals to render cleanly to multiple output
media favours structural rather than presentational markup,
however the classical man(7) macros remain almost exclusively
presentational. mdoc(7) provides a semantically superior
alternative, but the use of man(7) is deeply rooted in Unix.
  Future work on manpages will entail improving the semantic
clarity of the man(7) macros, decoupling them as much as possible
from low-level presentational requests.  The aim will be to ease
conversion of manpages to markup languages that do not rely on
groff for display and printing, e.g. XML, while preserving the full
presentational richness of manpages processed with groff.
  Concurrent with work on man(7), mdoc(7) will be actively supported
and its use promoted.
  To summarize, the goal of this two-pronged strategy is to foster
manpage markup that
  - renders cleanly to the terminal
  - respects presentational markup when output to PostScript
  - allows semantic analysis
  - is portable

LOOKING FORWARD, LOOKING BACK

  Backward compatibility with existing documents and usage will
remain a top priority, as will avoiding feature-bloat and increased
overheads.  Groff's viability and vitality rest as much on these as
on forward-looking development.
  Finally, it is hoped that users of and contributors to groff
will promote its use, providing unobtrusive advocacy to encourage
more widespread adoption of the program, thereby increasing the pool
of potential contributors and developers and furthering the cause of
good typography.

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-- 
Peter Schaffter
http://www.schaffter.ca