[5264] do not break at leading - or -- in code

[karl]

Revision: 5264
          http://svn.sv.gnu.org/viewvc/?view=rev&root=texinfo&revision=5264
Author:   karl
Date:     2013-06-23 17:30:11 +0000 (Sun, 23 Jun 2013)
Log Message:
-----------
do not break at leading - or -- in code

Modified Paths:
--------------
    trunk/ChangeLog
    trunk/doc/texinfo.tex

Modified: trunk/ChangeLog
===================================================================
--- trunk/ChangeLog     2013-06-21 23:20:50 UTC (rev 5263)
+++ trunk/ChangeLog     2013-06-23 17:30:11 UTC (rev 5264)
@@ -1,5 +1,12 @@
 2013-06-21  Karl Berry  <address@hidden>
 
+       * doc/texinfo.tex (\codedash): use \futurelet.
+       (\codedashfinish): new definition for - inside @code et al.,
+       which does not allow a break after a - when it is preceded or
+       followed by another -, or when it is first.
+       (\code): initialize \codedashprev for the - as first char case.
+       Report from Arnold Robbins, 04 Apr 2013 01:30:28 -0600.
+
        * texi2dvi (run_makeinfo): more verbose error message if our
        test reading texinfo.tex fails.  Suggestion from Vincent B,
        25 May 2013 23:10:58.

Modified: trunk/doc/texinfo.tex
===================================================================
--- trunk/doc/texinfo.tex       2013-06-21 23:20:50 UTC (rev 5263)
+++ trunk/doc/texinfo.tex       2013-06-23 17:30:11 UTC (rev 5264)
@@ -3,7 +3,7 @@
 % Load plain if necessary, i.e., if running under initex.
 \expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi
 %
-\def\texinfoversion{2013-03-19.11}
+\def\texinfoversion{2013-06-21.17}
 %
 % Copyright 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995,
 % 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
@@ -2475,14 +2475,14 @@
 }
 
 % We *must* turn on hyphenation at `-' and `_' in @code.
+% (But see \codedashfinish below.)
 % Otherwise, it is too hard to avoid overfull hboxes
 % in the Emacs manual, the Library manual, etc.
 %
 % Unfortunately, TeX uses one parameter (\hyphenchar) to control
 % both hyphenation at - and hyphenation within words.
 % We must therefore turn them both off (\tclose does that)
-% and arrange explicitly to hyphenate at a dash.
-%  -- rms.
+% and arrange explicitly to hyphenate at a dash. -- rms.
 {
   \catcode`\-=\active \catcode`\_=\active
   \catcode`\'=\active \catcode`\`=\active
@@ -2499,14 +2499,33 @@
      \let-\normaldash
      \let_\realunder
     \fi
+    % Given -foo (with a single dash), we do not want to allow a break
+    % after the hyphen.
+    \global\let\codedashprev=\codedash
+    %
     \codex
   }
+  %
+  \gdef\codedash{\futurelet\next\codedashfinish}
+  \gdef\codedashfinish{%
+    \normaldash % always output the dash character itself.
+    % 
+    % Now, output a discretionary to allow a line break, unless
+    % (a) the next character is a -, or
+    % (b) the preceding character is a -.
+    % E.g., given --posix, we do not want to allow a break after either -.
+    % Given --foo-bar, we do want to allow a break between the - and the b.
+    \ifx\next\codedash \else
+      \ifx\codedashprev\codedash 
+      \else \discretionary{}{}{}\fi
+    \fi
+    \global\let\codedashprev=\next
+  }
 }
-
+\def\normaldash{-}
+%
 \def\codex #1{\tclose{#1}\endgroup}
 
-\def\normaldash{-}
-\def\codedash{-\discretionary{}{}{}}
 \def\codeunder{%
   % this is all so @address@hidden can work.  In math mode, _
   % is "active" (mathcode"8000) and \normalunderscore (or \char95, etc.)