************************************************************************
* Official mandoc TODO.
* $Id: TODO,v 1.1.1.1 2013/04/03 14:46:49 christos Exp $
************************************************************************

************************************************************************
* parser bugs
************************************************************************

- ".\}" on its own line gets translated to bare ".\&"
  which forces pset() into man(7)
  and then triggers an unknown macro error
  reported by naddy@  Sun, 3 Jul 2011 21:52:24 +0200

************************************************************************
* formatter bugs
************************************************************************

- tbl(7): Horizontal and vertical lines are formatted badly:
  With the box option, there is too much white space at the end of cells.
  Horizontal lines from "=" lines are a bit too long.
  yuri dot pankov at gmail dot com  Thu, 14 Apr 2011 05:45:26 +0400

************************************************************************
* missing features
************************************************************************

--- missing roff features ----------------------------------------------

- The pod2man preamble wants \h'...' with quoted numerical arguments,
  see for example AUTHORS in MooseX::Getopt.3p, p5-MooseX-Getopt.
  reported by Andreas Voegele <mail at andreasvoegele dot com>
  Tue, 22 Nov 2011 15:34:47 +0100 on ports@

- .if n \{
  .br\}
  should cause an extra space to be raised.

- .ad (adjust margins)
  .ad l -- adjust left margin only (flush left)
  .ad r -- adjust right margin only (flush right)
  .ad c -- center text on line
  .ad b -- adjust both margins (alias: .ad n)
  .na   -- temporarily disable adjustment without changing the mode
  .ad   -- re-enable adjustment without changing the mode
  Adjustment mode is ignored while in no-fill mode (.nf).

- .it (line traps) occur in mysql(1), yasm_arch(7)
  generated by DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
  reported by brad@  Sat, 15 Jan 2011 15:48:18 -0500

- .ns (no-space mode) occurs in xine-config(1)
  reported by brad@  Sat, 15 Jan 2011 15:45:23 -0500

- xloadimage(1) wants .ti (temporary indent), rep by naddy@

- .ta (tab settings) occurs in ircbug(1) and probably gnats(1)
  reported by brad@  Sat, 15 Jan 2011 15:50:51 -0500

- \c (interrupted text) occurs in chat(8)

- using undefined strings or macros defines them to be empty
  wl@  Mon, 14 Nov 2011 14:37:01 +0000

--- missing mdoc features ----------------------------------------------

- fix bad block nesting involving multiple identical explicit blocks
  see the OpenBSD mdoc_macro.c 1.47 commit message

- .Bl -column .Xo support is missing
  ultimate goal:
  restore .Xr and .Dv to
  lib/libc/compat-43/sigvec.3
  lib/libc/gen/signal.3
  lib/libc/sys/sigaction.2

- edge case: decide how to deal with blk_full bad nesting, e.g.
  .Sh .Nm .Bk .Nm .Ek .Sh found by jmc@ in ssh-keygen(1)
  from jmc@  Wed, 14 Jul 2010 18:10:32 +0100

- \\ is now implemented correctly
  * when defining strings and macros using .ds and .de
  * when parsing roff(7) and man(7) macro arguments
  It does not yet work in mdoc(7) macro arguments
  because libmdoc does not yet use mandoc_getarg().
  Also check what happens in plain text, it must be identical to \e.

- .Bd -filled should not be the same as .Bd -ragged, but align both
  the left and right margin.  In groff, it is implemented in terms
  of .ad b, which we don't have either.  Found in cksum(1).

- implement blank `Bl -column', such as
  .Bl -column
  .It foo Ta bar
  .El

- explicitly disallow nested `Bl -column', which would clobber internal
  flags defined for struct mdoc_macro

- In .Bl -column .It, the end of the line probably has to be regarded
  as an implicit .Ta, if there could be one, see the following mildly
  ugly code from login.conf(5):
    .Bl -column minpasswordlen program xetcxmotd
    .It path Ta path Ta value of Dv _PATH_DEFPATH
    .br
    Default search path.
  reported by Michal Mazurek <akfaew at jasminek dot net>
  via jmc@ Thu, 7 Apr 2011 16:00:53 +0059

- inside `.Bl -column' phrases, punctuation is handled like normal
  text, e.g. `.Bl -column .It Fl x . Ta ...' should give "-x -."

- inside `.Bl -column' phrases, TERMP_IGNDELIM handling by `Pf'
  is not safe, e.g. `.Bl -column .It Pf a b .' gives "ab."
  but should give "ab ."

- set a meaningful default if no `Bl' list type is assigned

- have a blank `It' head for `Bl -tag' not puke

- prohibit `Nm' from having non-text HEAD children
  (e.g., NetBSD mDNSShared/dns-sd.1)
  (mdoc_html.c and mdoc_term.c `Nm' handlers can be slightly simplified)

- When there is free text in the SYNOPSIS and that free text contains
  the .Nm macro, groff somehow understands to treat the .Nm as an in-line
  macro, while mandoc treats it as a block macro and breaks the line.
  No idea how the logic for distinguishing in-line and block instances
  should be, needs investigation.
  uqs@  Thu, 2 Jun 2011 11:03:51 +0200
  uqs@  Thu, 2 Jun 2011 11:33:35 +0200

--- missing man features -----------------------------------------------

- groff an-ext.tmac macros (.UR, .UE) occur in xine(5)
  reported by brad@  Sat, 15 Jan 2011 15:45:23 -0500

- -T[x]html doesn't stipulate non-collapsing spaces in literal mode

--- missing tbl features -----------------------------------------------

- implement basic non-parametric .de to support e.g. sox(1)
  reported by naddy@ Sat, 16 Oct 2010 23:51:57 +0200
  *** sox(1) still doesn't work, tbl(1) errors need investigation

- allow standalone `.' to be interpreted as an end-of-layout
  delimiter instead of being thrown away as a no-op roff line
  reported by Yuri Pankov, Wed 18 May 2011 11:34:59 CEST

--- missing misc features ----------------------------------------------

- clean up escape sequence handling, creating three classes:
  (1) fully implemented, or parsed and ignored without loss of content
  (2) unimplemented, potentially causing loss of content
      or serious mangling of formatting (e.g. \n) -> ERROR
      see textproc/mgdiff(1) for nice examples
  (3) undefined, just output the character -> perhaps WARNING

- The \t escape sequence is the same as a literal tab, see for example
  the ASCII table in hexdump(1) where
    .Bl -column \&000_nu \&001_so \&002_st \&003_et \&004_eo
    .It \&000\ nul\t001\ soh\t002\ stx\t003\ etx\t004\ eot\t005\ enq
  produces
    000 nul  001 soh  002 stx  003 etx  004 eot  005 enq
  and the example in oldrdist(1)

- look at pages generated from reStructeredText, e.g. devel/mercurial hg(1)
  These are a weird mixture of man(7) and custom autogenerated low-level
  roff stuff.  Figure out to what extent we can cope.
  For details, see http://docutils.sourceforge.net/rst.html
  noted by stsp@  Sat, 24 Apr 2010 09:17:55 +0200
  reminded by nicm@  Mon, 3 May 2010 09:52:41 +0100

- check compatibility with Plan9:
  http://swtch.com/usr/local/plan9/tmac/tmac.an
  http://swtch.com/plan9port/man/man7/man.html
  "Anthony J. Bentley" <anthonyjbentley@gmail.com> 28 Dec 2010 21:58:40 -0700

************************************************************************
* formatting issues: ugly output
************************************************************************

- a column list with blank `Ta' cells triggers a spurrious
  start-with-whitespace printing of a newline

- double quotes inside double quotes are escaped by doubling them
  implement this in mdoc(7), too
  so far, we only have it in roff(7) and man(7)
  reminded by millert@  Thu, 09 Dec 2010 17:29:52 -0500

- perl(1) SYNOPSIS looks bad; reported by deraadt@
  1) man(7) seems to need SYNOPSIS .Nm blocks, too

- In .Bl -column,
  .It Em Authentication<tab>Key Length
  ought to render "Key Length" with emphasis, too,
  see OpenBSD iked.conf(5).
  reported again Nicolas Joly via wiz@ Wed, 12 Oct 2011 00:20:00 +0200

- empty phrases in .Bl column produce too few blanks
  try e.g. .Bl -column It Ta Ta
  reported by millert Fri, 02 Apr 2010 16:13:46 -0400

- .%T can have trailing punctuation.  Currently, it puts the trailing
  punctuation into a trailing MDOC_TEXT element inside its own scope.
  That element should rather be outside its scope, such that the
  punctuation does not get underlines.  This is not trivial to
  implement because .%T then needs some features of in_line_eoln() -
  slurp all arguments into one single text element - and one feature
  of in_line() - put trailing punctuation out of scope.
  Found in mount_nfs(8) and exports(5), search for "Appendix".

- in enclosures, mandoc sometimes fancies a bogus end of sentence
  reminded by jmc@  Thu, 23 Sep 2010 18:13:39 +0059

************************************************************************
* formatting issues: gratuitous differences
************************************************************************

- .Rv (and probably .Ex) print different text if an `Nm' has been named
  or not (run a manual without `Nm blah' to see this).  I'm not sure
  that this exists in the wild, but it's still an error.

- In .Bl -bullet, the groff bullet is "+\b+\bo\bo", the mandoc bullet
  is just "o\bo".
  see for example OpenBSD ksh(1)

- The characters "|" and "\*(Ba" should never be bold,
  not even in the middle of a word, e.g. ".Cm b\*(Bac" in
  "mknod [-m mode] name b|c major minor"
  in OpenBSD ksh(1)

- A bogus .Pp between two .It must not produce a double blank line,
  see between -R and -r in OpenBSD rm(1), before "update" in mount(8),
  or in DIAGNOSTICS in init(8), or before "is always true" in ksh(1).
  The same happens with .Pp just before .El, see bgpd.conf(5).
  Also have `It' complain if `Pp' is invoked at certain times (not
  -compact?).

- .Pp between two .It in .Bl -column should produce one,
  not two blank lines, see e.g. login.conf(5).
  reported by jmc@  Sun, 17 Apr 2011 14:04:58 +0059
  reported again by sthen@  Wed, 18 Jan 2012 02:09:39 +0000 (UTC)

- If the *first* line after .It is .Pp, break the line right after
  the tag, do not pad with space characters before breaking.
  See the description of the a, c, and i commands in sed(1).

- If the first line after .It is .D1, do not assert a blank line
  in between, see for example tmux(1).
  reported by nicm@  13 Jan 2011 00:18:57 +0000

- .Nx 1.0a
  should be "NetBSD 1.0A", not "NetBSD 1.0a",
  see OpenBSD ccdconfig(8).

- In .Bl -tag, if a tag exceeds the right margin and must be continued
  on the next line, it must be indented by -width, not width+1;
  see "rule block|pass" in OpenBSD ifconfig(8).

- When the -width string contains macros, the macros must be rendered
  before measuring the width, for example
    .Bl -tag -width ".Dv message"
  in magic(5), located in src/usr.bin/file, is the same
  as -width 7n, not -width 11n.
  The same applies to .Bl -column column widths;
  reported again by Nicolas Joly Thu, 1 Mar 2012 13:41:26 +0100 via wiz@ 5 Mar

- The \& zero-width character counts as output.
  That is, when it is alone on a line between two .Pp,
  we want three blank lines, not two as in mandoc.

- When .Fn arguments exceed one output line, all but the first
  should be indented, see e.g. rpc(3);
  reported by jmc@ on discuss@  Fri, 29 Oct 2010 13:48:33 +0100
  reported again by Nicolas Joly via wiz@  Sun, 18 Sep 2011 18:24:40 +0200
  Also, we don't want to break the line within the argument of:
  .Fa "chtype tl"

- .Ns should work when called at the end of an input line, see
  the following code in vi(1):
    .It Xo
    .Op Ar line
    .Cm a Ns Op Cm ppend Ns
    .Op Cm !\&
    .Xc
    The input text is appended after the specified line.

- Header lines of excessive length:
  Port OpenBSD man_term.c rev. 1.25 to mdoc_term.c
  and document it in mdoc(7) and man(7) COMPATIBILITY
  found while talking to Chris Bennett

- In man(7), the sequence
    .HP
    one line of regular text
    .SH
  should not produce two blank lines before the .SH,
  see for example named-checkconf(8).

- In man(7), the sequence
    .SH HEADER
    <blank line>
    .PP
    regular text
  should not produce any blank lines between the header and the text,
  see for example rsync(1).
  Reported by naddy@  Mon, 28 Mar 2011 20:45:42 +0200

- In man(7), the sequence
    regular text
    .IP
    .IP "tag"
    indented text
  should produce one, not four blank lines between the regular text
  and the tag, see for example rsync(1).
  Likewise,
    regular text
    .IP
    indented text
  should produce one, not two blank lines in between, and
    regular text
    .IP
    .RS
    .IP tag
    indented text
  should produce one, not three blank lines.
  Reported by naddy@  Mon, 28 Mar 2011 20:45:42 +0200

- trailing whitespace must be ignored even when followed by a font escape,
  see for example 
    makes
    \fBdig \fR
    operate in batch mode
  in dig(1).

************************************************************************
* error reporting issues
************************************************************************

- .TP directly followed by .RS gives an assertion.

************************************************************************
* performance issues
************************************************************************

Several areas can be cleaned up to make mandoc even faster.  These are 

- improve hashing mechanism for macros (quite important: performance)

- improve hashing mechanism for characters (not as important)

- the PDF file is HUGE: this can be reduced by using relative offsets

- instead of re-initialising the roff predefined-strings set before each
  parse, create a read-only version the first time and copy it 

************************************************************************
* structural issues
************************************************************************

- We use the input line number at several places to distinguish
  same-line from different-line input.  That plainly doesn't work
  with user-defined macros, leading to random breakage.

- Find better ways to prevent endless loops
  in roff(7) macro and string expansion.
 
- Finish cleanup of date handling.
  Decide which formats should be recognized where.
  Update both mdoc(7) and man(7) documentation.
  Triggered by  Tim van der Molen  Tue, 22 Feb 2011 20:30:45 +0100
