TODO

   1 ************************************************************************
   2 * Official mandoc TODO.
   3 * $Id: TODO,v 1.234 2017/02/18 11:53:33 schwarze Exp $
   4 ************************************************************************
   5
   6 Many issues are annotated for difficulty as follows:
   7
   8  - loc = locality of the issue
   9     *    single file issue, affects file only, or very few
  10     **   single module issue, affects several files of one module
  11     ***  cross-module issue, significantly impacts multiple modules
  12          and may require substantial changes to internal interfaces
  13  - exist = difficulty of the existing code in this area
  14     *    affected code is straightforward and easy to read and change
  15     **   affected code is somewhat complex, but once you understand
  16          the design, not particularly difficult to understand
  17     ***  affected code uses a special, exceptionally tricky design
  18  - algo = difficulty of the new algorithm to be written
  19     *    the required logic and code is straightforward
  20     **   the required logic is somewhat complex and needs a careful design
  21     ***  the required logic is exceptionally tricky,
  22          maybe an approach to solve that is not even known yet
  23  - size = the amount of code to be written or changed
  24     *    a small number of lines (at most 100, usually much less)
  25     **   a considerable amount of code (several dozen to a few hundred)
  26     ***  a large amount of code (many hundreds, maybe thousands)
  27  - imp = importance of the issue
  28     *    mostly for completeness
  29     **   would be nice to have
  30     ***  issue causes considerable inconvenience
  31
  32 Obviously, as the issues have not been solved yet, these annotations
  33 are mere guesses, and some may be wrong.
  34
  35 ************************************************************************
  36 * missing features
  37 ************************************************************************
  38
  39 --- missing roff features ----------------------------------------------
  40
  41 - .ad (adjust margins)
  42   .ad l -- adjust left margin only (flush left)
  43   .ad r -- adjust right margin only (flush right)
  44   .ad c -- center text on line
  45   .ad b -- adjust both margins (alias: .ad n)
  46   .na   -- temporarily disable adjustment without changing the mode
  47   .ad   -- re-enable adjustment without changing the mode
  48   Adjustment mode is ignored while in no-fill mode (.nf).
  49   loc ***  exist ***  algo **  size **  imp **  (parser reorg would help)
  50
  51 - .fc (field control)
  52   found by naddy@ in xloadimage(1)
  53   loc **  exist ***  algo *  size *  imp *
  54
  55 - .nr third argument (auto-increment step size, requires \n+)
  56   found by bentley@ in sbcl(1)  Mon, 9 Dec 2013 18:36:57 -0700
  57   loc *  exist *  algo *  size *  imp **
  58
  59 - .ns (no-space mode) occurs in xine-config(1)
  60   when implementing this, also let .TH set it
  61   reported by brad@  Sat, 15 Jan 2011 15:45:23 -0500
  62   loc ***  exist ***  algo ***  size **  imp *
  63
  64 - .ta (tab settings)
  65   #1 most important issue naddy@ Mon, 16 Feb 2015 20:59:17 +0100
  66   ircbug(1) gnats(1) reported by brad@  Sat, 15 Jan 2011 15:50:51 -0500
  67   also Tcl_NewStringObj(3) via wiz@  Wed, 5 Mar 2014 22:27:43 +0100
  68   also posix2time(3) Carsten Kunze  Mon, 1 Dec 2014 13:03:10 +0100
  69   loc **  exist ***  algo **  size **  imp ***
  70
  71 - .ti (temporary indent)
  72   found by naddy@ in xloadimage(1) [devel/libvstr] vstr(3)
  73   found by bentley@ in nmh(1)  Mon, 23 Apr 2012 13:38:28 -0600
  74   loc **  exist **  algo **  size *  imp ** (parser reorg helps a lot)
  75
  76 - .while and .shift
  77   found by jca@ in ratpoison(1)  Sun, 30 Jun 2013 12:01:09 +0200
  78   loc *  exist **  algo **  size **  imp **
  79
  80 - \h horizontal move
  81   #2 most important issue naddy@  Mon, 16 Feb 2015 20:59:17 +0100
  82   found in cclive(1) nasm(1) bogofilter(1) asciidoc/DocBook output
  83   bentley@ on discuss@  Sat, 21 Sep 2013 22:29:34 -0600
  84   naddy@  Thu, 4 Dec 2014 16:26:41 +0100
  85   loc **  exist **  algo **  size *  imp *** (parser reorg helps a lot)
  86
  87 - \n+ and \n- numerical register increment and decrement
  88   found by bentley@ in sbcl(1)  Mon, 9 Dec 2013 18:36:57 -0700
  89   loc *  exist *  algo *  size *  imp **
  90
  91 - \n(.$ macro argument count number register; ocserv(8) by autogen
  92   found by sthen@  Thu, 19 Feb 2015 22:03:01 +0000
  93   loc *  exist **  algo *  size *  imp **
  94
  95 - \w'' improve width measurements
  96   would not be very useful without an expression parser, see below
  97   needed for Tcl_NewStringObj(3) via wiz@  Wed, 5 Mar 2014 22:27:43 +0100
  98   loc **  exist ***  algo ***  size *  imp ***
  99
 100 - \\ in high-level macro arguments
 101   Currently, \\ is expanded in two situations:
 102   1) macro and string definition (roff.c setstrn())
 103   2) macro argument parsing (mandoc.c mandoc_getarg())
 104   For user defined macros, the second happens in time because of ROFF_REPARSE.
 105   But for standard high-level macros, it only happens after entering the
 106   high level parsers, which is too late because the code doesn't get
 107   back to roff.c roff_res() from that point.  Because this requires
 108   distinguishing requests, user-defined macros and standard macros
 109   on the roff_res() level, it is hard to solve without the parser reorg.
 110   Found by naddy@ in devel/cutils cobfusc(1)  Mon, 16 Feb 2015 19:10:52 +0100
 111   loc ***  exist ***  algo ***  size **  imp *
 112
 113 - using undefined strings or macros defines them to be empty
 114   wl@  Mon, 14 Nov 2011 14:37:01 +0000
 115   loc *  exist *  algo *  size *  imp *
 116
 117 --- missing mdoc features ----------------------------------------------
 118
 119 - .Bl -column .Xo support is missing
 120   ultimate goal:
 121   restore .Xr and .Dv to
 122   lib/libc/compat-43/sigvec.3
 123   lib/libc/gen/signal.3
 124   lib/libc/sys/sigaction.2
 125   loc *  exist ***  algo ***  size *  imp **
 126
 127 - edge case: decide how to deal with blk_full bad nesting, e.g.
 128   .Sh .Nm .Bk .Nm .Ek .Sh found by jmc@ in ssh-keygen(1)
 129   from jmc@  Wed, 14 Jul 2010 18:10:32 +0100
 130   loc *  exist ***  algo ***  size **  imp **
 131
 132 - .Bd -centered implies -filled, not -unfilled, which is not
 133   easy to implement; it requires code similar to .ce, which
 134   we don't have either.
 135   Besides, groff has bug causing text right *before* .Bd -centered
 136   to be centered as well.
 137   loc ***  exist ***  algo **  size **  imp **  (parser reorg would help)
 138
 139 - .Bd -filled should not be the same as .Bd -ragged, but align both
 140   the left and right margin.  In groff, it is implemented in terms
 141   of .ad b, which we don't have either.  Found in cksum(1).
 142   loc ***  exist ***  algo **  size **  imp **  (parser reorg would help)
 143
 144 - implement blank `Bl -column', such as
 145   .Bl -column
 146   .It foo Ta bar
 147   .El
 148   loc *  exist ***  algo ***  size *  imp *
 149
 150 - explicitly disallow nested `Bl -column', which would clobber internal
 151   flags defined for struct mdoc_macro
 152   loc *  exist *  algo *  size *  imp **
 153
 154 - In .Bl -column .It, the end of the line probably has to be regarded
 155   as an implicit .Ta, if there could be one, see the following mildly
 156   ugly code from login.conf(5):
 157     .Bl -column minpasswordlen program xetcxmotd
 158     .It path Ta path Ta value of Dv _PATH_DEFPATH
 159     .br
 160     Default search path.
 161   reported by Michal Mazurek <akfaew at jasminek dot net>
 162   via jmc@ Thu, 7 Apr 2011 16:00:53 +0059
 163   loc *  exist ***  algo **  size *  imp **
 164
 165 - inside `.Bl -column' phrases, punctuation is handled like normal
 166   text, e.g. `.Bl -column .It Fl x . Ta ...' should give "-x -."
 167
 168 - inside `.Bl -column' phrases, TERMP_IGNDELIM handling by `Pf'
 169   is not safe, e.g. `.Bl -column .It Pf a b .' gives "ab."
 170   but should give "ab ."
 171
 172 - check whether it is correct that `D1' uses INDENT+1;
 173   does it need its own constant?
 174   loc *  exist **  algo **  size *  imp **
 175
 176 - prohibit `Nm' from having non-text HEAD children
 177   (e.g., NetBSD mDNSShared/dns-sd.1)
 178   (mdoc_html.c and mdoc_term.c `Nm' handlers can be slightly simplified)
 179
 180 - support translated section names
 181   e.g. x11/scrotwm scrotwm_es.1:21:2: error: NAME section must be first
 182   that one uses NOMBRE because it is spanish...
 183   deraadt tends to think that section-dependent macro behaviour
 184   is a bad idea in the first place, so this may be irrelevant
 185   loc **  exist **  algo **  size *  imp **
 186
 187 - When there is free text in the SYNOPSIS and that free text contains
 188   the .Nm macro, groff somehow understands to treat the .Nm as an in-line
 189   macro, while mandoc treats it as a block macro and breaks the line.
 190   No idea how the logic for distinguishing in-line and block instances
 191   should be, needs investigation.
 192   uqs@  Thu, 2 Jun 2011 11:03:51 +0200
 193   uqs@  Thu, 2 Jun 2011 11:33:35 +0200
 194   loc *  exist **  algo ***  size *  imp **
 195
 196 --- missing tbl features -----------------------------------------------
 197
 198 - horizontal lines in the layout still consume data cells
 199   and can be mixed with actual data on the same table line
 200   synaptics(4) found by tedu@  Mon, 17 Aug 2015 21:17:42 -0400
 201   loc **  exist **  algo **  size **  imp ***
 202
 203 - break long text into lines inside cells
 204   net/lftp(1) from jirib via bentley@ Sep 13, 2016
 205
 206 - layout l1 for a column of max text width 3 reduces the following
 207   inter-column spacing for groff, but not for mandoc
 208   net/lftp(1) from jirib via bentley@ Sep 13, 2016
 209
 210 - the "w" layout option is ignored
 211   synaptics(4) found by tedu@  Mon, 17 Aug 2015 21:17:42 -0400
 212   loc *  exist *  algo *  size *  imp **
 213
 214 - the "s" layout column specifier is used for placement of data
 215   into columns, but ignored during column width calculations
 216   synaptics(4) found by tedu@  Mon, 17 Aug 2015 21:17:42 -0400
 217   loc *  exist **  algo ***  size *  imp **
 218
 219 - support mdoc(7) and man(7) macros inside tbl(7) code;
 220   probably requires the parser reorg and letting tbl(7)
 221   use roff_node such that macro sets can mix;
 222   informed by bapt@ that FreeBSD needs this: 3 Jan 2015 23:32:23 +0100
 223   loc ***  exist **  algo ***  size **  imp ***
 224
 225 - look at the POSIX manuals in the books/man-pages-posix port,
 226   they use some unsupported tbl(7) features.
 227   loc *  exist **  algo **  size **  imp ***
 228
 229 - look what Joerg Schilling manual pages use
 230   Thu, 19 Mar 2015 18:31:48 +0100
 231
 232 - use Unicode U+2500 to U+256C for table borders
 233   in tbl(7) -Tutf-8 output
 234   suggested by bentley@  Tue, 14 Oct 2014 04:10:55 -0600
 235   loc *  exist **  algo *  size *  imp **
 236
 237 --- missing eqn features -----------------------------------------------
 238
 239 - In a matrix, break the output line after each matrix line.
 240   Found in the discussion at CDBUG 2015.
 241   Suggested by Avi Weinstock.
 242   loc *  exist *  algo *  size *  imp **
 243
 244 - The "size" keyword is parsed, but ignored by the formatter.
 245   loc *  exist *  algo *  size *  imp *
 246
 247 - The spacing characters `~', `^', and tab are currently ignored,
 248   see User's Guide (Second Edition) page 2 section 4.
 249   loc *  exist *  algo **  size *  imp **
 250
 251 - Mark and lineup are parsed and ignored,
 252   see User's Guide (Second Edition) page 5 section 15.
 253   loc **  exist **  algo **  size **  imp **
 254
 255 --- missing misc features ----------------------------------------------
 256
 257 - italic correction (\/) in PostScript mode
 258   Werner LEMBERG on groff at gnu dot org  Sun, 10 Nov 2013 12:47:46
 259   loc **  exist **  algo *  size *  imp *
 260
 261 - change the default PAGER to more -Es and use the pager
 262   even for apropos title line output; req by bapt@
 263   loc *  exist *  algo *  size *  imp ***
 264
 265 - clean up escape sequence handling, creating three classes:
 266   (1) fully implemented, or parsed and ignored without loss of content
 267   (2) unimplemented, potentially causing loss of content
 268       or serious mangling of formatting (e.g. \n) -> ERROR
 269       see textproc/mgdiff(1) for nice examples
 270   (3) undefined, just output the character -> perhaps WARNING
 271   loc ***  exist **  algo **  size **  imp *** (parser reorg helps)
 272
 273 - kettenis wants base roff, ms, and me  Fri, 1 Jan 2010 22:13:15 +0100 (CET)
 274   loc **  exist **  algo **  size ***  imp *
 275
 276 - Vsevolod Stakhov (FreeBSD) needs either a markdown output formatter
 277   for mandoc -mdoc or a markdown to mdoc converter because they
 278   have to maintain manuals needed both in markdown and mdoc format.
 279   Look at the libsoldout (markdown -> whatever)
 280   loc *  exist *  algo *  size **  imp **
 281
 282 --- compatibility checks -----------------------------------------------
 283
 284 - is .Bk implemented correctly in modern groff?
 285   sobrado@  Tue, 19 Apr 2011 22:12:55 +0200
 286
 287 - compare output to Heirloom roff, Solaris roff, and
 288   http://repo.or.cz/w/neatroff.git  http://litcave.rudi.ir/
 289
 290 - look at AT&T DWB http://www2.research.att.com/sw/download
 291   Carsten Kunze <carsten dot kunze at arcor dot de> has patches
 292   Mon, 4 Aug 2014 17:01:28 +0200
 293   ported version: https://github.com/n-t-roff/DWB3.3
 294   Carsten Kunze  Wed, 22 Apr 2015 11:21:43 +0200
 295
 296 - look at pages generated from reStructeredText, e.g. devel/mercurial hg(1)
 297   These are a weird mixture of man(7) and custom autogenerated low-level
 298   roff stuff.  Figure out to what extent we can cope.
 299   For details, see http://docutils.sourceforge.net/rst.html
 300   noted by stsp@  Sat, 24 Apr 2010 09:17:55 +0200
 301   reminded by nicm@  Mon, 3 May 2010 09:52:41 +0100
 302
 303 - look at pages generated from ronn(1) github.com/rtomayko/ronn
 304   (based on markdown)
 305
 306 - look at pages generated from Texinfo source by yat2m, e.g. security/gnupg
 307   First impression is not that bad.
 308
 309 - look at pages generated by pandoc; see
 310   https://github.com/jgm/pandoc/blob/master/src/Text/Pandoc/Writers/Man.hs
 311   porting planned by kili@  Thu, 19 Jun 2014 19:46:28 +0200
 312
 313 - check compatibility with Plan9:
 314   http://swtch.com/usr/local/plan9/tmac/tmac.an
 315   http://swtch.com/plan9port/man/man7/man.html
 316   "Anthony J. Bentley" <anthonyjbentley@gmail.com> 28 Dec 2010 21:58:40 -0700
 317
 318 - check compatibility with COHERENT troff:
 319   http://www.nesssoftware.com/home/mwc/source.php
 320
 321 - check compatibility with the man(7) formatter
 322   https://raw.githubusercontent.com/rofl0r/hardcore-utils/master/man.c
 323
 324 - check compatibility with
 325   http://ikiwiki.info/plugins/contrib/mandoc/
 326   https://github.com/schmonz/ikiwiki/compare/mandoc
 327   Amitai Schlair  Mon, 19 May 2014 14:05:53 -0400
 328
 329 - check features of the Slackware man.conf(5) format
 330   Carsten Kunze  Wed, 11 Mar 2015 17:57:24 +0100
 331
 332 ************************************************************************
 333 * formatting issues: ugly output
 334 ************************************************************************
 335
 336 - revisit empty in-line macros
 337   look at the difference between "Em x Em ." and "Sq x Em ."
 338   Carsten Kunze  Fri, 12 Dec 2014 00:15:41 +0100
 339   loc *** exist *** algo *** size * imp **
 340
 341 - a column list with blank `Ta' cells triggers a spurious
 342   start-with-whitespace printing of a newline
 343
 344 - In .Bl -column, .It a<tab>"b<tab>c"
 345   shows the quotes in groff, but not in mandoc
 346   loc * exist *** algo ** size * imp **
 347
 348 - In .Bl -column,
 349   .It Em Authentication<tab>Key Length
 350   ought to render "Key Length" with emphasis, too,
 351   see OpenBSD iked.conf(5).
 352   reported again Nicolas Joly via wiz@ Wed, 12 Oct 2011 00:20:00 +0200
 353   loc *  exist ***  algo ***  size **  imp ***
 354
 355 - empty phrases in .Bl column produce too few blanks
 356   try e.g. .Bl -column It Ta Ta
 357   reported by millert Fri, 02 Apr 2010 16:13:46 -0400
 358   loc *  exist ***  algo ***  size *  imp **
 359
 360 - .%T can have trailing punctuation.  Currently, it puts the trailing
 361   punctuation into a trailing MDOC_TEXT element inside its own scope.
 362   That element should rather be outside its scope, such that the
 363   punctuation does not get underlines.  This is not trivial to
 364   implement because .%T then needs some features of in_line_eoln() -
 365   slurp all arguments into one single text element - and one feature
 366   of in_line() - put trailing punctuation out of scope.
 367   Found in mount_nfs(8) and exports(5), search for "Appendix".
 368   loc **  exist **  algo ***  size *  imp **
 369
 370 - Trailing punctuation after .%T triggers EOS spacing, at least
 371   outside .Rs (eek!).  Simply setting ARGSFL_DELIM for .%T is not
 372   the right solution, it sends mandoc into an endless loop.
 373   reported by Nicolas Joly  Sat, 17 Nov 2012 11:49:54 +0100
 374   loc *  exist **  algo **  size *  imp **
 375
 376 - global variables in the SYNOPSIS of section 3 pages
 377   .Vt vs .Vt/.Va vs .Ft/.Va vs .Ft/.Fa ...
 378   from kristaps@  Tue, 08 Jun 2010 11:13:32 +0200
 379
 380 - in enclosures, mandoc sometimes fancies a bogus end of sentence
 381   reminded by jmc@  Thu, 23 Sep 2010 18:13:39 +0059
 382   loc *  exist **  algo ***  size *  imp ***
 383
 384 - a line starting with "\fB something" counts as starting with whitespace
 385   and triggers a line break; found in audio/normalize-mp3(1)
 386   loc **  exist *  algo **  size *  imp **
 387
 388 - formatting /usr/local/man/man1/latex2man.1 with groff and mandoc
 389   reveals lots of bugs both in groff and mandoc...
 390   reported by bentley@  Wed, 22 May 2013 23:49:30 -0600
 391
 392 --- PostScript and PDF issues ------------------------------------------
 393
 394 - PDF output doesn't use a monospaced font for .Bd -literal
 395   Example: "mandoc -Tpdf afterboot.8 > output.pdf && pdfviewer output.pdf".
 396   Search the text "Routing tables".
 397   Also check what PostScript mode does when fixing this.
 398   reported by juanfra@ Wed, 04 Jun 2014 21:44:58 +0200
 399   instructions from juanfra@  Wed, 11 Jun 2014 02:21:01 +0200
 400     add a new <</Type /Font>> block to the PDF files with /BaseFont /Courier
 401     and change the /Name from /F0 to the new font (/F5 (?)).
 402   re-reported by tb@ Mon, 16 Mar 2015 16:47:21 +0100
 403   loc *  exist **  algo **  size *  imp **
 404
 405 --- HTML issues --------------------------------------------------------
 406
 407 - .Bf at the beginning of a paragraph inserts a bogus 1ex horizontal
 408   space, see for example random(3).  Introduced in
 409   http://mdocml.bsd.lv/cgi-bin/cvsweb/mdoc_html.c.diff?r1=1.91&r2=1.92
 410   reported by deraadt@ Mon, 28 Sep 2015 20:14:13 -0600 (MDT)
 411   loc **  exist **  algo **  size *  imp *
 412
 413 - jsg on icb, Nov 3, 2014:
 414   try to guess Xr in man(7) for hyperlinking
 415   and render them with <a class="Xr" href=...>
 416   https://github.com/Debian/debiman/issues/15
 417   loc *  exist *  algo **  size **  imp **
 418
 419 - The tables used to render the three-part page headers actually force
 420   the width of the <body> to the max-width given for <html>.
 421   Not yet sure how to fix that...
 422   Observed by an Anonymous Coward on undeadly.org:
 423   http://undeadly.org/cgi?action=article&sid=20140925064244&pid=1
 424   loc *  exist *  algo **  size *  imp ***
 425
 426 - generate <img> tags in HTML
 427   idea from florian@  Tue, 7 Apr 2015 00:26:28 +0000
 428   may be possible to implement with .Lk img://something.png alt_text
 429
 430 - check https://github.com/trentm/mdocml
 431
 432 ************************************************************************
 433 * formatting issues: gratuitous differences
 434 ************************************************************************
 435
 436 - .Fn reopens a new scope after punctuation in mandoc,
 437   but closes its scope for good in groff.
 438   Do we want to change mandoc or groff?
 439   Steffen Nurpmeso  Sat, 08 Nov 2014 13:34:59 +0100
 440   loc *  exist **  algo **  size *  imp **
 441
 442 - .Lk formatting for long links with line breaks
 443   Franco Fichtner  8 Oct 2013 00:33:42 +0200
 444
 445 - In .Bl -enum -width 0n, groff continues one the same line after
 446   the number, mandoc breaks the line.
 447   mail to kristaps@  Mon, 20 Jul 2009 02:21:39 +0200
 448   loc *  exist **  algo **  size *  imp **
 449
 450 - .Pp between two .It in .Bl -column should produce one,
 451   not two blank lines, see e.g. login.conf(5).
 452   reported by jmc@  Sun, 17 Apr 2011 14:04:58 +0059
 453   reported again by sthen@  Wed, 18 Jan 2012 02:09:39 +0000 (UTC)
 454   loc *  exist ***  algo **  size *  imp **
 455
 456 - If the *first* line after .It is .Pp, break the line right after
 457   the tag, do not pad with space characters before breaking.
 458   See the description of the a, c, and i commands in sed(1).
 459   loc *  exist **  algo **  size *  imp **
 460
 461 - If the first line after .It is .D1, do not assert a blank line
 462   in between, see for example tmux(1).
 463   reported by nicm@  13 Jan 2011 00:18:57 +0000
 464   loc *  exist **  algo **  size *  imp **
 465
 466 - Trailing punctuation after .It should trigger EOS spacing.
 467   reported by Nicolas Joly  Sat, 17 Nov 2012 11:49:54 +0100
 468   Probably, this should be fixed somewhere in termp_it_pre(), not sure.
 469   loc *  exist **  algo **  size *  imp **
 470
 471 - .Nx 1.0a
 472   should be "NetBSD 1.0A", not "NetBSD 1.0a",
 473   see OpenBSD ccdconfig(8).
 474   loc *  exist *  algo *  size *  imp **
 475
 476 - In .Bl -tag, if a tag exceeds the right margin and must be continued
 477   on the next line, it must be indented by -width, not width+1;
 478   see "rule block|pass" in OpenBSD ifconfig(8).
 479   loc *  exist ***  algo **  size *  imp **
 480
 481 - When the -width string contains macros, the macros must be rendered
 482   before measuring the width, for example
 483     .Bl -tag -width ".Dv message"
 484   in magic(5), located in src/usr.bin/file, is the same
 485   as -width 7n, not -width 11n.
 486   The same applies to .Bl -column column widths;
 487   reported again by Nicolas Joly Thu, 1 Mar 2012 13:41:26 +0100 via wiz@ 5 Mar
 488   reported again by Franco Fichtner Fri, 27 Sep 2013 21:02:28 +0200
 489   reported again by Bruce Evans Fri, 17 Feb 2017 21:22:44 +0100 via bapt@
 490   loc ***  exist ***  algo ***  size **  imp ***
 491   An easy partial fix would be to just skip the first word if it starts
 492   with a dot, including any following white space, when measuring.
 493   loc *  exist *  algo *  size *  imp ***
 494
 495 - The \& zero-width character counts as output.
 496   That is, when it is alone on a line between two .Pp,
 497   we want three blank lines, not two as in mandoc.
 498   loc **  exist **  algo **  size *  imp **
 499
 500 - Sequences of multiple man(7) paragraphs (.PP, .IP) interspersed
 501   with .ps and .nf/.fi produce execessive blank lines, see libJudy
 502   and graphics/dcmtk.  The parser reorg may help with this.
 503
 504 - trailing whitespace must be ignored even when followed by a font escape,
 505   see for example
 506     makes
 507     \fBdig \fR
 508     operate in batch mode
 509   in dig(1).
 510   loc **  exist **  algo **  size *  imp **
 511
 512 ************************************************************************
 513 * warning issues
 514 ************************************************************************
 515
 516 - provide a way in mandoc(1) to warn about broken .Xr links;
 517   probably cannot be on by default in -Tlint because it needs
 518   to access the manpath and mandoc.db(3) after parsing.
 519   asked for by jmc@ Fri, 4 Dec 2015 22:39:40 +0000
 520
 521 - warn when .Sh or .Ss contain other macros
 522   Steffen Nurpmeso, savannah.gnu.org/bugs/index.php?45034
 523   loc *  exist *  algo *  size *  imp **
 524
 525 - warn about attempts to call non-callable macros
 526   Steffen Nurpmeso  Tue, 11 Nov 2014 22:55:16 +0100
 527   Note that formatting is inconsistent in groff.
 528   .Fn Po prints "Po()", .Ar Sh prints "file ..." and no "Sh".
 529   Relatively hard because the relevant code is scattered
 530   all over mdoc_macro.c and all subtly different.
 531   loc **  exist **  algo **  size **  imp **
 532
 533 - mandoc_special does not really check the escape sequence,
 534   but just the overall format
 535   loc **  exist **  algo ***  size **  imp **
 536
 537 - integrate mdoclint into mandoc ("end-of-line whitespace" thread)
 538   from jmc@  Mon, 13 Jul 2009 17:12:09 +0100
 539   from kristaps@  Mon, 13 Jul 2009 18:34:53 +0200
 540   from jmc@  Mon, 13 Jul 2009 17:45:37 +0059
 541   from kristaps@  Mon, 13 Jul 2009 19:02:03 +0200
 542   (mostly done, check what remains)
 543
 544 - -Tlint parser errors and warnings to stdout
 545   to tech@mdocml, naddy@  Wed, 28 Sep 2011 11:21:46 +0200
 546   wait!  kristaps@  Sun, 02 Oct 2011 17:12:52 +0200
 547
 548 ************************************************************************
 549 * documentation issues
 550 ************************************************************************
 551
 552 - mark macros as: page structure domain, manual domain, general text domain
 553   is this useful?
 554
 555 - mention /usr/share/misc/mdoc.template in mdoc(7)?
 556
 557 - Is all the content from http://www.std.com/obi/BSD/doc/usd/28.tbl/tbl
 558   covered in tbl(7)?
 559
 560 ************************************************************************
 561 * performance issues
 562 ************************************************************************
 563
 564 - Why are we using MAP_SHARED, not MAP_PRIVATE for mmap(2)?
 565   from kristaps@  Sat, 09 Aug 2014 13:51:36 +0200
 566
 567 Several areas can be cleaned up to make mandoc even faster.  These are
 568
 569 - improve hashing mechanism for macros (quite important: performance)
 570
 571 - the PDF file is HUGE: this can be reduced by using relative offsets
 572
 573 ************************************************************************
 574 * structural issues
 575 ************************************************************************
 576
 577 - POSIX says in the documentation of sysconf(3) that PATH_MAX
 578   is allowed to be so large that it is a bad idea to use it
 579   for sizing static buffers.  So use dynamic buffers throughout.
 580   See the file test-PATH_MAX.c for details.
 581   Found by Aaron M. Ucko in the GNU Hurd via Bdale Garbee,
 582   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=829624
 583
 584 - We use the input line number at several places to distinguish
 585   same-line from different-line input.  That plainly doesn't work
 586   with user-defined macros, leading to random breakage.
 587
 588 - Find better ways to prevent endless loops
 589   in roff(7) macro and string expansion.
 590
 591 - Finish cleanup of date handling.
 592   Decide which formats should be recognized where.
 593   Update both mdoc(7) and man(7) documentation.
 594   Triggered by  Tim van der Molen  Tue, 22 Feb 2011 20:30:45 +0100
 595
 596 - struct mparse refactoring
 597   Steffen Nurpmeso  Thu, 04 Sep 2014 12:50:00 +0200
 598
 599 ************************************************************************
 600 * CGI issues
 601 ************************************************************************
 602
 603  - Enable HTTP compression by detecting gzip encoding and filtering
 604    output through libz.
 605  - Sandbox (see OpenSSH).
 606  - Enable caching support via HTTP 304 and If-Modified-Since.
 607  - Have Mac OSX systems automatically disable -static compilation of the
 608    CGI: -static isn't supported.
 609
 610 ************************************************************************
 611 * to improve in the groff_mdoc(7) macros
 612 ************************************************************************
 613
 614 - use uname(1) to set doc-default-operating-system at install time
 615   tobimensch  Mon, 1 Dec 2014 00:25:07 +0100