TODO

   1 ************************************************************************
   2 * Official mandoc TODO.
   3 * $Id: TODO,v 1.213 2015/08/29 15:10:28 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 * crashes
  37 ************************************************************************
  38
  39 - The abort() in bufcat(), html.c, can be triggered via buffmt_includes()
  40   by running -Thtml -Oincludes on a file containing a long .In argument.
  41   Fixing this will probably require reworking the whole bufcat() concept.
  42   loc **  exist *  algo *  size **  imp **
  43
  44 ************************************************************************
  45 * missing features
  46 ************************************************************************
  47
  48 --- missing roff features ----------------------------------------------
  49
  50 - .ad (adjust margins)
  51   .ad l -- adjust left margin only (flush left)
  52   .ad r -- adjust right margin only (flush right)
  53   .ad c -- center text on line
  54   .ad b -- adjust both margins (alias: .ad n)
  55   .na   -- temporarily disable adjustment without changing the mode
  56   .ad   -- re-enable adjustment without changing the mode
  57   Adjustment mode is ignored while in no-fill mode (.nf).
  58   loc ***  exist ***  algo **  size **  imp **  (parser reorg would help)
  59
  60 - .fc (field control)
  61   found by naddy@ in xloadimage(1)
  62   loc **  exist ***  algo *  size *  imp *
  63
  64 - .nr third argument (auto-increment step size, requires \n+)
  65   found by bentley@ in sbcl(1)  Mon, 9 Dec 2013 18:36:57 -0700
  66   loc *  exist *  algo *  size *  imp **
  67
  68 - .ns (no-space mode) occurs in xine-config(1)
  69   when implementing this, also let .TH set it
  70   reported by brad@  Sat, 15 Jan 2011 15:45:23 -0500
  71   loc ***  exist ***  algo ***  size **  imp *
  72
  73 - .ta (tab settings)
  74   #1 most important issue naddy@ Mon, 16 Feb 2015 20:59:17 +0100
  75   ircbug(1) gnats(1) reported by brad@  Sat, 15 Jan 2011 15:50:51 -0500
  76   also Tcl_NewStringObj(3) via wiz@  Wed, 5 Mar 2014 22:27:43 +0100
  77   also posix2time(3) Carsten Kunze  Mon, 1 Dec 2014 13:03:10 +0100
  78   loc **  exist ***  algo **  size **  imp ***
  79
  80 - .ti (temporary indent)
  81   found by naddy@ in xloadimage(1) [devel/libvstr] vstr(3)
  82   found by bentley@ in nmh(1)  Mon, 23 Apr 2012 13:38:28 -0600
  83   loc **  exist **  algo **  size *  imp ** (parser reorg helps a lot)
  84
  85 - .while and .shift
  86   found by jca@ in ratpoison(1)  Sun, 30 Jun 2013 12:01:09 +0200
  87   loc *  exist **  algo **  size **  imp **
  88
  89 - \h horizontal move
  90   #2 most important issue naddy@  Mon, 16 Feb 2015 20:59:17 +0100
  91   found in cclive(1) nasm(1) bogofilter(1) asciidoc/DocBook output
  92   bentley@ on discuss@  Sat, 21 Sep 2013 22:29:34 -0600
  93   naddy@  Thu, 4 Dec 2014 16:26:41 +0100
  94   loc **  exist **  algo **  size *  imp *** (parser reorg helps a lot)
  95
  96 - \n+ and \n- numerical register increment and decrement
  97   found by bentley@ in sbcl(1)  Mon, 9 Dec 2013 18:36:57 -0700
  98   loc *  exist *  algo *  size *  imp **
  99
 100 - \n(.$ macro argument count number register; ocserv(8) by autogen
 101   found by sthen@  Thu, 19 Feb 2015 22:03:01 +0000
 102   loc *  exist **  algo *  size *  imp **
 103
 104 - \w'' improve width measurements
 105   would not be very useful without an expression parser, see below
 106   needed for Tcl_NewStringObj(3) via wiz@  Wed, 5 Mar 2014 22:27:43 +0100
 107   loc **  exist ***  algo ***  size *  imp ***
 108
 109 - \\ in high-level macro arguments
 110   Currently, \\ is expanded in two situations:
 111   1) macro and string definition (roff.c setstrn())
 112   2) macro argument parsing (mandoc.c mandoc_getarg())
 113   For user defined macros, the second happens in time because of ROFF_REPARSE.
 114   But for standard high-level macros, it only happens after entering the
 115   high level parsers, which is too late because the code doesn't get
 116   back to roff.c roff_res() from that point.  Because this requires
 117   distinguishing requests, user-defined macros and standard macros
 118   on the roff_res() level, it is hard to solve without the parser reorg.
 119   Found by naddy@ in devel/cutils cobfusc(1)  Mon, 16 Feb 2015 19:10:52 +0100
 120   loc ***  exist ***  algo ***  size **  imp *
 121
 122 - using undefined strings or macros defines them to be empty
 123   wl@  Mon, 14 Nov 2011 14:37:01 +0000
 124   loc *  exist *  algo *  size *  imp *
 125
 126 --- missing mdoc features ----------------------------------------------
 127
 128 - .Bl -column .Xo support is missing
 129   ultimate goal:
 130   restore .Xr and .Dv to
 131   lib/libc/compat-43/sigvec.3
 132   lib/libc/gen/signal.3
 133   lib/libc/sys/sigaction.2
 134   loc *  exist ***  algo ***  size *  imp **
 135
 136 - edge case: decide how to deal with blk_full bad nesting, e.g.
 137   .Sh .Nm .Bk .Nm .Ek .Sh found by jmc@ in ssh-keygen(1)
 138   from jmc@  Wed, 14 Jul 2010 18:10:32 +0100
 139   loc *  exist ***  algo ***  size **  imp **
 140
 141 - .Bd -centered implies -filled, not -unfilled, which is not
 142   easy to implement; it requires code similar to .ce, which
 143   we don't have either.
 144   Besides, groff has bug causing text right *before* .Bd -centered
 145   to be centered as well.
 146   loc ***  exist ***  algo **  size **  imp **  (parser reorg would help)
 147
 148 - .Bd -filled should not be the same as .Bd -ragged, but align both
 149   the left and right margin.  In groff, it is implemented in terms
 150   of .ad b, which we don't have either.  Found in cksum(1).
 151   loc ***  exist ***  algo **  size **  imp **  (parser reorg would help)
 152
 153 - implement blank `Bl -column', such as
 154   .Bl -column
 155   .It foo Ta bar
 156   .El
 157   loc *  exist ***  algo ***  size *  imp *
 158
 159 - explicitly disallow nested `Bl -column', which would clobber internal
 160   flags defined for struct mdoc_macro
 161   loc *  exist *  algo *  size *  imp **
 162
 163 - In .Bl -column .It, the end of the line probably has to be regarded
 164   as an implicit .Ta, if there could be one, see the following mildly
 165   ugly code from login.conf(5):
 166     .Bl -column minpasswordlen program xetcxmotd
 167     .It path Ta path Ta value of Dv _PATH_DEFPATH
 168     .br
 169     Default search path.
 170   reported by Michal Mazurek <akfaew at jasminek dot net>
 171   via jmc@ Thu, 7 Apr 2011 16:00:53 +0059
 172   loc *  exist ***  algo **  size *  imp **
 173
 174 - inside `.Bl -column' phrases, punctuation is handled like normal
 175   text, e.g. `.Bl -column .It Fl x . Ta ...' should give "-x -."
 176
 177 - inside `.Bl -column' phrases, TERMP_IGNDELIM handling by `Pf'
 178   is not safe, e.g. `.Bl -column .It Pf a b .' gives "ab."
 179   but should give "ab ."
 180
 181 - check whether it is correct that `D1' uses INDENT+1;
 182   does it need its own constant?
 183   loc *  exist **  algo **  size *  imp **
 184
 185 - prohibit `Nm' from having non-text HEAD children
 186   (e.g., NetBSD mDNSShared/dns-sd.1)
 187   (mdoc_html.c and mdoc_term.c `Nm' handlers can be slightly simplified)
 188
 189 - support translated section names
 190   e.g. x11/scrotwm scrotwm_es.1:21:2: error: NAME section must be first
 191   that one uses NOMBRE because it is spanish...
 192   deraadt tends to think that section-dependent macro behaviour
 193   is a bad idea in the first place, so this may be irrelevant
 194   loc **  exist **  algo **  size *  imp **
 195
 196 - When there is free text in the SYNOPSIS and that free text contains
 197   the .Nm macro, groff somehow understands to treat the .Nm as an in-line
 198   macro, while mandoc treats it as a block macro and breaks the line.
 199   No idea how the logic for distinguishing in-line and block instances
 200   should be, needs investigation.
 201   uqs@  Thu, 2 Jun 2011 11:03:51 +0200
 202   uqs@  Thu, 2 Jun 2011 11:33:35 +0200
 203   loc *  exist **  algo ***  size *  imp **
 204
 205 --- missing man features -----------------------------------------------
 206
 207 - -T[x]html doesn't stipulate non-collapsing spaces in literal mode
 208
 209 --- missing tbl features -----------------------------------------------
 210
 211 - horizontal lines in the layout still consume data cells
 212   and can be mixed with actual data on the same table line
 213   synaptics(4) found by tedu@  Mon, 17 Aug 2015 21:17:42 -0400
 214   loc **  exist **  algo **  size **  imp ***
 215
 216 - the "w" layout option is ignored
 217   synaptics(4) found by tedu@  Mon, 17 Aug 2015 21:17:42 -0400
 218   loc *  exist *  algo *  size *  imp **
 219
 220 - the "s" layout column specifier is used for placement of data
 221   into columns, but ignored during column width calculations
 222   synaptics(4) found by tedu@  Mon, 17 Aug 2015 21:17:42 -0400
 223   loc *  exist **  algo ***  size *  imp **
 224
 225 - support mdoc(7) and man(7) macros inside tbl(7) code;
 226   probably requires the parser reorg and letting tbl(7)
 227   use roff_node such that macro sets can mix;
 228   informed by bapt@ that FreeBSD needs this.
 229   loc ***  exist **  algo ***  size **  imp ***
 230
 231 - look at the POSIX manuals in the books/man-pages-posix port,
 232   they use some unsupported tbl(7) features.
 233   loc *  exist **  algo **  size **  imp ***
 234
 235 - use Unicode U+2500 to U+256C for table borders
 236   in tbl(7) -Tutf-8 output
 237   suggested by bentley@  Tue, 14 Oct 2014 04:10:55 -0600
 238   loc *  exist **  algo *  size *  imp **
 239
 240 --- missing eqn features -----------------------------------------------
 241
 242 - In a matrix, break the output line after each matrix line.
 243   Found in the discussion at CDBUG 2015.
 244   Suggested by Avi Weinstock.
 245   loc *  exist *  algo *  size *  imp **
 246
 247 - The "size" keyword is parsed, but ignored by the formatter.
 248   loc *  exist *  algo *  size *  imp *
 249
 250 - The spacing characters `~', `^', and tab are currently ignored,
 251   see User's Guide (Second Edition) page 2 section 4.
 252   loc *  exist *  algo **  size *  imp **
 253
 254 - Mark and lineup are parsed and ignored,
 255   see User's Guide (Second Edition) page 5 section 15.
 256   loc **  exist **  algo **  size **  imp **
 257
 258 --- missing misc features ----------------------------------------------
 259
 260 - italic correction (\/) in PostScript mode
 261   Werner LEMBERG on groff at gnu dot org  Sun, 10 Nov 2013 12:47:46
 262   loc **  exist **  algo *  size *  imp *
 263
 264 - change the default PAGER to more -Es and use the pager
 265   even for apropos title line output; req by bapt@
 266   loc *  exist *  algo *  size *  imp ***
 267
 268 - makewhatis(8) for preformatted pages:
 269   parse the section number from the header line
 270   and compare to the section number from the directory name
 271   loc *  exist *  algo *  size *  imp **
 272
 273 - Does makewhatis(8) detect missing NAME sections, missing names,
 274   and missing descriptions in all the file formats?
 275   loc *  exist *  algo *  size *  imp ***
 276
 277 - clean up escape sequence handling, creating three classes:
 278   (1) fully implemented, or parsed and ignored without loss of content
 279   (2) unimplemented, potentially causing loss of content
 280       or serious mangling of formatting (e.g. \n) -> ERROR
 281       see textproc/mgdiff(1) for nice examples
 282   (3) undefined, just output the character -> perhaps WARNING
 283   loc ***  exist **  algo **  size **  imp *** (parser reorg helps)
 284
 285 - kettenis wants base roff, ms, and me  Fri, 1 Jan 2010 22:13:15 +0100 (CET)
 286   loc **  exist **  algo **  size ***  imp *
 287
 288 - Vsevolod Stakhov (FreeBSD) needs either a markdown output formatter
 289   for mandoc -mdoc or a markdown to mdoc converter because they
 290   have to maintain manuals needed both in markdown and mdoc format.
 291   Look at the libsoldout (markdown -> whatever)
 292   loc *  exist *  algo *  size **  imp **
 293
 294 --- compatibility checks -----------------------------------------------
 295
 296 - is .Bk implemented correctly in modern groff?
 297   sobrado@  Tue, 19 Apr 2011 22:12:55 +0200
 298
 299 - compare output to Heirloom roff, Solaris roff, and
 300   http://repo.or.cz/w/neatroff.git  http://litcave.rudi.ir/
 301
 302 - look at AT&T DWB http://www2.research.att.com/sw/download
 303   Carsten Kunze <carsten dot kunze at arcor dot de> has patches
 304   Mon, 4 Aug 2014 17:01:28 +0200
 305
 306 - look at pages generated from reStructeredText, e.g. devel/mercurial hg(1)
 307   These are a weird mixture of man(7) and custom autogenerated low-level
 308   roff stuff.  Figure out to what extent we can cope.
 309   For details, see http://docutils.sourceforge.net/rst.html
 310   noted by stsp@  Sat, 24 Apr 2010 09:17:55 +0200
 311   reminded by nicm@  Mon, 3 May 2010 09:52:41 +0100
 312
 313 - look at pages generated from ronn(1) github.com/rtomayko/ronn
 314   (based on markdown)
 315
 316 - look at pages generated from Texinfo source by yat2m, e.g. security/gnupg
 317   First impression is not that bad.
 318
 319 - look at pages generated by pandoc; see
 320   https://github.com/jgm/pandoc/blob/master/src/Text/Pandoc/Writers/Man.hs
 321   porting planned by kili@  Thu, 19 Jun 2014 19:46:28 +0200
 322
 323 - check compatibility with Plan9:
 324   http://swtch.com/usr/local/plan9/tmac/tmac.an
 325   http://swtch.com/plan9port/man/man7/man.html
 326   "Anthony J. Bentley" <anthonyjbentley@gmail.com> 28 Dec 2010 21:58:40 -0700
 327
 328 - check compatibility with COHERENT troff:
 329   http://www.nesssoftware.com/home/mwc/source.php
 330
 331 - check compatibility with the man(7) formatter
 332   https://raw.githubusercontent.com/rofl0r/hardcore-utils/master/man.c
 333
 334 - check compatibility with
 335   http://ikiwiki.info/plugins/contrib/mandoc/
 336   https://github.com/schmonz/ikiwiki/compare/mandoc
 337   Amitai Schlair  Mon, 19 May 2014 14:05:53 -0400
 338
 339 ************************************************************************
 340 * formatting issues: ugly output
 341 ************************************************************************
 342
 343 - revisit empty in-line macros
 344   look at the difference between "Em x Em ." and "Sq x Em ."
 345   Carsten Kunze  Fri, 12 Dec 2014 00:15:41 +0100
 346   loc *** exist *** algo *** size * imp **
 347
 348 - a column list with blank `Ta' cells triggers a spurious
 349   start-with-whitespace printing of a newline
 350
 351 - In .Bl -column, .It a<tab>"b<tab>c"
 352   shows the quotes in groff, but not in mandoc
 353   loc * exist *** algo ** size * imp **
 354
 355 - In .Bl -column,
 356   .It Em Authentication<tab>Key Length
 357   ought to render "Key Length" with emphasis, too,
 358   see OpenBSD iked.conf(5).
 359   reported again Nicolas Joly via wiz@ Wed, 12 Oct 2011 00:20:00 +0200
 360   loc *  exist ***  algo ***  size **  imp ***
 361
 362 - empty phrases in .Bl column produce too few blanks
 363   try e.g. .Bl -column It Ta Ta
 364   reported by millert Fri, 02 Apr 2010 16:13:46 -0400
 365   loc *  exist ***  algo ***  size *  imp **
 366
 367 - .%T can have trailing punctuation.  Currently, it puts the trailing
 368   punctuation into a trailing MDOC_TEXT element inside its own scope.
 369   That element should rather be outside its scope, such that the
 370   punctuation does not get underlines.  This is not trivial to
 371   implement because .%T then needs some features of in_line_eoln() -
 372   slurp all arguments into one single text element - and one feature
 373   of in_line() - put trailing punctuation out of scope.
 374   Found in mount_nfs(8) and exports(5), search for "Appendix".
 375   loc **  exist **  algo ***  size *  imp **
 376
 377 - Trailing punctuation after .%T triggers EOS spacing, at least
 378   outside .Rs (eek!).  Simply setting ARGSFL_DELIM for .%T is not
 379   the right solution, it sends mandoc into an endless loop.
 380   reported by Nicolas Joly  Sat, 17 Nov 2012 11:49:54 +0100
 381   loc *  exist **  algo **  size *  imp **
 382
 383 - global variables in the SYNOPSIS of section 3 pages
 384   .Vt vs .Vt/.Va vs .Ft/.Va vs .Ft/.Fa ...
 385   from kristaps@  Tue, 08 Jun 2010 11:13:32 +0200
 386
 387 - in enclosures, mandoc sometimes fancies a bogus end of sentence
 388   reminded by jmc@  Thu, 23 Sep 2010 18:13:39 +0059
 389   loc *  exist **  algo ***  size *  imp ***
 390
 391 - a line starting with "\fB something" counts as starting with whitespace
 392   and triggers a line break; found in audio/normalize-mp3(1)
 393   loc **  exist *  algo **  size *  imp **
 394
 395 - formatting /usr/local/man/man1/latex2man.1 with groff and mandoc
 396   reveals lots of bugs both in groff and mandoc...
 397   reported by bentley@  Wed, 22 May 2013 23:49:30 -0600
 398
 399 --- PDF issues ---------------------------------------------------------
 400
 401 - PDF output doesn't use a monospaced font for .Bd -literal
 402   Example: "mandoc -Tpdf afterboot.8 > output.pdf && pdfviewer output.pdf".
 403   Search the text "Routing tables".
 404   Also check what PostScript mode does when fixing this.
 405   reported by juanfra@ Wed, 04 Jun 2014 21:44:58 +0200
 406   instructions from juanfra@  Wed, 11 Jun 2014 02:21:01 +0200
 407     add a new <</Type /Font>> block to the PDF files with /BaseFont /Courier
 408     and change the /Name from /F0 to the new font (/F5 (?)).
 409   loc *  exist **  algo **  size *  imp **
 410
 411 --- HTML issues --------------------------------------------------------
 412
 413 - <dl><dt><dd> formatting is ugly
 414   hints are easy to find on the web, e.g.
 415   http://stackoverflow.com/questions/1713048/
 416   see also matthew@  Fri, 18 Jul 2014 19:25:12 -0700
 417   loc *  exist *  algo **  size *  imp ***
 418
 419 - jsg on icb, Nov 3, 2014:
 420   try to guess Xr in man(7) for hyperlinking
 421
 422 - The tables used to render the three-part page headers actually force
 423   the width of the <body> to the max-width given for <html>.
 424   Not yet sure how to fix that...
 425   Observed by an Anonymous Coward on undeadly.org:
 426   http://undeadly.org/cgi?action=article&sid=20140925064244&pid=1
 427   loc *  exist *  algo **  size *  imp ***
 428
 429 - consider whether <var> can be used for Ar Dv Er Ev Fa Va.
 430   from bentley@  Wed, 13 Aug 2014 09:17:55 -0600
 431
 432 - generate <img> tags in HTML
 433   idea from florian@  Tue, 7 Apr 2015 00:26:28 +0000
 434   may be possible to implement with .Lk img://something.png alt_text
 435
 436 - check https://github.com/trentm/mdocml
 437
 438 ************************************************************************
 439 * formatting issues: gratuitous differences
 440 ************************************************************************
 441
 442 - .Fn reopens a new scope after punctuation in mandoc,
 443   but closes its scope for good in groff.
 444   Do we want to change mandoc or groff?
 445   Steffen Nurpmeso  Sat, 08 Nov 2014 13:34:59 +0100
 446   loc *  exist **  algo **  size *  imp **
 447
 448 - In .Bl -enum -width 0n, groff continues one the same line after
 449   the number, mandoc breaks the line.
 450   mail to kristaps@  Mon, 20 Jul 2009 02:21:39 +0200
 451   loc *  exist **  algo **  size *  imp **
 452
 453 - .Pp between two .It in .Bl -column should produce one,
 454   not two blank lines, see e.g. login.conf(5).
 455   reported by jmc@  Sun, 17 Apr 2011 14:04:58 +0059
 456   reported again by sthen@  Wed, 18 Jan 2012 02:09:39 +0000 (UTC)
 457   loc *  exist ***  algo **  size *  imp **
 458
 459 - If the *first* line after .It is .Pp, break the line right after
 460   the tag, do not pad with space characters before breaking.
 461   See the description of the a, c, and i commands in sed(1).
 462   loc *  exist **  algo **  size *  imp **
 463
 464 - If the first line after .It is .D1, do not assert a blank line
 465   in between, see for example tmux(1).
 466   reported by nicm@  13 Jan 2011 00:18:57 +0000
 467   loc *  exist **  algo **  size *  imp **
 468
 469 - Trailing punctuation after .It should trigger EOS spacing.
 470   reported by Nicolas Joly  Sat, 17 Nov 2012 11:49:54 +0100
 471   Probably, this should be fixed somewhere in termp_it_pre(), not sure.
 472   loc *  exist **  algo **  size *  imp **
 473
 474 - .Nx 1.0a
 475   should be "NetBSD 1.0A", not "NetBSD 1.0a",
 476   see OpenBSD ccdconfig(8).
 477   loc *  exist *  algo *  size *  imp **
 478
 479 - In .Bl -tag, if a tag exceeds the right margin and must be continued
 480   on the next line, it must be indented by -width, not width+1;
 481   see "rule block|pass" in OpenBSD ifconfig(8).
 482   loc *  exist ***  algo **  size *  imp **
 483
 484 - When the -width string contains macros, the macros must be rendered
 485   before measuring the width, for example
 486     .Bl -tag -width ".Dv message"
 487   in magic(5), located in src/usr.bin/file, is the same
 488   as -width 7n, not -width 11n.
 489   The same applies to .Bl -column column widths;
 490   reported again by Nicolas Joly Thu, 1 Mar 2012 13:41:26 +0100 via wiz@ 5 Mar
 491   reported again by Franco Fichtner Fri, 27 Sep 2013 21:02:28 +0200
 492   loc ***  exist ***  algo ***  size **  imp ***
 493   An easy partial fix would be to just skip the first word if it starts
 494   with a dot, including any following white space, when measuring.
 495   loc *  exist *  algo *  size *  imp ***
 496
 497 - The \& zero-width character counts as output.
 498   That is, when it is alone on a line between two .Pp,
 499   we want three blank lines, not two as in mandoc.
 500   loc **  exist **  algo **  size *  imp **
 501
 502 - Header lines of excessive length:
 503   Port OpenBSD man_term.c rev. 1.25 to mdoc_term.c
 504   and document it in mdoc(7) and man(7) COMPATIBILITY
 505   found while talking to Chris Bennett
 506   loc *  exist *  algo *  size *  imp *
 507
 508 - Sequences of multiple man(7) paragraphs (.PP, .IP) interspersed
 509   with .ps and .nf/.fi produce execessive blank lines, see libJudy
 510   and graphics/dcmtk.  The parser reorg may help with this.
 511
 512 - trailing whitespace must be ignored even when followed by a font escape,
 513   see for example
 514     makes
 515     \fBdig \fR
 516     operate in batch mode
 517   in dig(1).
 518   loc **  exist **  algo **  size *  imp **
 519
 520 ************************************************************************
 521 * portability
 522 ************************************************************************
 523
 524 - word boundaries in regular expressions for whatis(1)
 525   set up config tests to use [[:<:]], \<, or nothing
 526   Svyatoslav Mishyn  Wed, 17 Dec 2014 11:07:10 +0200
 527   reminded by Peter Bray Fri, 03 Apr 2015 23:02:16 +1100
 528   loc *  exist *  algo *  size *  imp *
 529
 530 - systems having UTF-8 but not en_US.UTF-8
 531   call locale(1) from ./configure, select a UTF-8-locale,
 532   and use that for test-wchar.c and term_ascii.c
 533   to Markus Waldeck  Sat, 18 Jul 2015 01:55:37 +0200
 534   loc *  exist *  algo *  size *  imp *
 535
 536 ************************************************************************
 537 * warning issues
 538 ************************************************************************
 539
 540 - Report errors in -O suboption parsing.
 541   loc *  exist *  algo *  size *  imp **
 542
 543 - warn when .Sh or .Ss contain other macros
 544   Steffen Nurpmeso, savannah.gnu.org/bugs/index.php?45034
 545   loc *  exist *  algo *  size *  imp **
 546
 547 - check that MANDOCERR_BADTAB is thrown in the right cases,
 548   i.e. when finding a literal tab character in fill mode,
 549   and possibly change the wording of the warning message
 550   to refer to fill mode, not literal mode
 551   See the mail from Werner LEMBERG on the groff list,
 552   Fri, 14 Feb 2014 18:54:42 +0100 (CET)
 553   loc *  exist **  algo **  size *  imp **
 554
 555 - warn about attempts to call non-callable macros
 556   Steffen Nurpmeso  Tue, 11 Nov 2014 22:55:16 +0100
 557   Note that formatting is inconsistent in groff.
 558   .Fn Po prints "Po()", .Ar Sh prints "file ..." and no "Sh".
 559   Relatively hard because the relevant code is scattered
 560   all over mdoc_macro.c and all subtly different.
 561   loc **  exist **  algo **  size **  imp **
 562
 563 - warn about "new sentence, new line"
 564   loc **  exist **  algo ***  size *  imp **
 565
 566 - mandoc_special does not really check the escape sequence,
 567   but just the overall format
 568   loc **  exist **  algo ***  size **  imp **
 569
 570 - integrate mdoclint into mandoc ("end-of-line whitespace" thread)
 571   from jmc@  Mon, 13 Jul 2009 17:12:09 +0100
 572   from kristaps@  Mon, 13 Jul 2009 18:34:53 +0200
 573   from jmc@  Mon, 13 Jul 2009 17:45:37 +0059
 574   from kristaps@  Mon, 13 Jul 2009 19:02:03 +0200
 575   (mostly done, check what remains)
 576
 577 - -Tlint parser errors and warnings to stdout
 578   to tech@mdocml, naddy@  Wed, 28 Sep 2011 11:21:46 +0200
 579   wait!  kristaps@  Sun, 02 Oct 2011 17:12:52 +0200
 580
 581 - for system errors, use errno/strerror/warn/err
 582
 583 ************************************************************************
 584 * documentation issues
 585 ************************************************************************
 586
 587 - mention hyphenation rules:
 588   breaking at letter-letter in text mode (not macro args)
 589   proper hyphenation is unimplemented
 590
 591 - talk about spacing around delimiters
 592   to jmc@, kristaps@  Sat, 23 Apr 2011 17:41:27 +0200
 593
 594 - mark macros as: page structure domain, manual domain, general text domain
 595   is this useful?
 596
 597 - mention /usr/share/misc/mdoc.template in mdoc(7)?
 598
 599 - Is all the content from http://www.std.com/obi/BSD/doc/usd/28.tbl/tbl
 600   covered in tbl(7)?
 601
 602 ************************************************************************
 603 * performance issues
 604 ************************************************************************
 605
 606 - Why are we using MAP_SHARED, not MAP_PRIVATE for mmap(2)?
 607   How does SQLITE_CONFIG_PAGECACHE actually work?  Document it!
 608   from kristaps@  Sat, 09 Aug 2014 13:51:36 +0200
 609
 610 Several areas can be cleaned up to make mandoc even faster.  These are
 611
 612 - improve hashing mechanism for macros (quite important: performance)
 613
 614 - improve hashing mechanism for characters (not as important)
 615
 616 - the PDF file is HUGE: this can be reduced by using relative offsets
 617
 618 - instead of re-initialising the roff predefined-strings set before each
 619   parse, create a read-only version the first time and copy it
 620   loc *  exist **  algo **  size *  imp **
 621
 622 ************************************************************************
 623 * structural issues
 624 ************************************************************************
 625
 626 - Use libz directly instead of forking gunzip(1).
 627   Suggested by bapt at FreeBSD among others.
 628
 629 - We use the input line number at several places to distinguish
 630   same-line from different-line input.  That plainly doesn't work
 631   with user-defined macros, leading to random breakage.
 632
 633 - Find better ways to prevent endless loops
 634   in roff(7) macro and string expansion.
 635
 636 - Finish cleanup of date handling.
 637   Decide which formats should be recognized where.
 638   Update both mdoc(7) and man(7) documentation.
 639   Triggered by  Tim van der Molen  Tue, 22 Feb 2011 20:30:45 +0100
 640
 641 - struct mparse refactoring
 642   Steffen Nurpmeso  Thu, 04 Sep 2014 12:50:00 +0200
 643
 644 - Consider creating some views that will make the database more
 645   readable from the sqlite3 shell.  Consider using them to
 646   abstract from the database structure, too.
 647   suggested by espie@  Sat, 19 Apr 2014 14:52:57 +0200
 648
 649 ************************************************************************
 650 * CGI issues
 651 ************************************************************************
 652
 653  - Enable HTTP compression by detecting gzip encoding and filtering
 654    output through libz.
 655  - Sandbox (see OpenSSH).
 656  - Enable caching support via HTTP 304 and If-Modified-Since.
 657  - Allow for cgi.h to be overridden by CGI environment variables.
 658    Otherwise, binary distributions will inherit the compile-time
 659    behaviour, which is not optimal.
 660  - Have Mac OSX systems automatically disable -static compilation of the
 661    CGI: -static isn't supported.
 662
 663 ************************************************************************
 664 * to improve in the groff_mdoc(7) macros
 665 ************************************************************************
 666
 667 - use uname(1) to set doc-default-operating-system at install time
 668   tobimensch  Mon, 1 Dec 2014 00:25:07 +0100