The groff ms macros are a complete re-implementation, using no
original AT&T code. Since they take advantage of the extended
features in groff, they cannot be used with AT&T troff. Other
differences include:
• The internals of groff ms differ from the internals of AT&T
ms. Documents that depend upon implementation details of AT&T
ms may not format properly with groff ms. Such details
include macros whose function was not documented in the AT&T
ms manual ('Typing Documents on the UNIX System: Using the -ms
Macros with Troff and Nroff', M. E. Lesk, Bell Laboratories,
1978).
• The error-handling policy of groff ms is to detect and report
errors, rather than silently to ignore them.
• Berkeley localisms, in particular the TM and CT macros, are
not implemented.
• Version 10 Research Unix supported a pair of P1 and P2 macros
for setting code examples; groff ms does not.
• groff ms does not work in GNU troff's AT&T compatibility mode.
If loaded when that mode is enabled, it aborts processing with
a diagnostic message.
• Multiple line spacing is not supported (use a larger vertical
spacing instead).
• groff ms uses the same header and footer defaults in both
nroff and troff modes as AT&T ms does in troff mode; AT&T's
default in nroff mode is to put the date, in U.S. traditional
format (e.g., 'January 1, 2021'), in the center footer (the CF
string).
• Macros that cause groff ms to internally reset its paragraph
rendering parameters (paragraphs, headings, and displays,
among others) may change the indentation; they do so not by
incrementing or decrementing it, but by setting it absolutely.
This can cause problems for documents that define additional
macros of their own that try to manipulate indentation. The
solution is to use, not the in request, but .RS and .RE.
• To make groff ms use the default page offset (which also
specifies the left margin), the PO register must stay
undefined until the first ms macro is called. This implies
that \n[PO] should not be used early in the document, unless
it is changed also: accessing an undefined register
automatically defines it.
• Displays are left-aligned by default, not indented. In AT&T
ms, .DS is synonymous with '.DS I'; in groff ms, it is
synonymous with '.DS L'.
• Block displays were not documented in the AT&T ms manual
(Berkeley corrected this oversight), but Version 7 Unix ms
supported them nevertheless, as does groff ms (this is thus
only an apparent difference).
• Right-aligned displays are available. The AT&T ms manual
observes that 'it is tempting to assume that '.DS R' will
right adjust lines, but it doesn't work'. In groff ms, it
does.
• groff ms handles 'S' as the first argument to the NH macro
specially, allowing alteration of the automatic heading
numbering sequence.
• groff ms supports the PN register, but it is not necessary;
you can access the page number via the usual % register and
use the af request to assign a different format to it if
desired. (If you redefine the ms PT macro and desire special
treatment of certain page numbers—like '1'—you may need to
handle a non-Arabic page number format, as groff ms's .PT
does; see the macro package source. groff ms aliases the PN
register to %.)
• The AT&T ms manual documents registers CW and GW as setting
the default column width and 'intercolumn gap', respectively,
and which applied when .MC was called with fewer than two
arguments. groff ms instead treats .MC without arguments as
synonymous with .2C; there is thus no occasion for a default
column width register. Further, the MINGW register and the
second argument to .MC specify a minimum space between
columns, not the fixed gutter width of AT&T ms.
• The register GS is set to 1 by the groff ms macros, but is not
used by the AT&T ms package. Documents that need to determine
whether they are being formatted with groff ms or another
implementation should test this register.
Localization strings
You can redefine the following strings to adapt the groff ms
macro package to languages other than English.
String Default
───────────────────────────────────
\*[REFERENCES] References
\*[ABSTRACT] \f[I]ABSTRACT\f[]
\*[TOC] Table of Contents
\*[MONTH1] January
\*[MONTH2] February
\*[MONTH3] March
\*[MONTH4] April
\*[MONTH5] May
\*[MONTH6] June
\*[MONTH7] July
\*[MONTH8] August
\*[MONTH9] September
\*[MONTH10] October
\*[MONTH11] November
\*[MONTH12] December
───────────────────────────────────
The default for ABSTRACT includes font style escapes to set the
word in italics.
