[PATCH] Error on read of over-long hex character constants.

GNU interpret "\xabcd" as containing one character, we interpret it as containing three. GNU interpret '(?\xffff) as a list containing a single integer (specified with character syntax), we interpret it as a list containing a character and a symbol with the string "ff" as its name. Our behaviour is more sane, since integer to character mappings above #xFF are not stable or particularly well-defined, neither in GNU Emacs nor XEmacs. Code written for the old behaviour is probably wrong, and is easily rewritten. In really old code, people would use ?\xffff instead of #xffff because GNU didn’t support hexadecimal integer read syntax. This isn’t an issue any more, the versions of GNU Emacs that don’t support #xFFFF are long obsolete. I’m about to post a patch detailing the packages changes necessary to support this change in the trunk. # HG changeset patch # User Aidan Kehoe <kehoea(a)parhasard.net&gt; # Date 1216240563 -7200 # Node ID 7869173584fcd40b83462f6acad1a9e7d8be3da1 # Parent ec442dc06fe1bc671fbe0ed0a928b294cdd45aba Error on over-long hex character escapes. 2008-07-16 Aidan Kehoe <kehoea(a)parhasard.net&gt; * lread.c (read_escape): Error if we're handed an over-long hex character escape, something which arises reasonably frequently in code written for GNU. diff -r ec442dc06fe1 -r 7869173584fc src/ChangeLog --- a/src/ChangeLog Thu Jul 10 23:37:52 2008 +0200 +++ b/src/ChangeLog Wed Jul 16 22:36:03 2008 +0200 ＠＠ -1,3 +1,9 ＠＠ +2008-07-16 Aidan Kehoe <kehoea(a)parhasard.net&gt; + + * lread.c (read_escape): + Error if we're handed an over-long hex character escape, something + which arises reasonably frequently in code written for GNU. + 2008-07-07 Aidan Kehoe <kehoea(a)parhasard.net&gt; Patch to make it up to the device-specific code whether diff -r ec442dc06fe1 -r 7869173584fc src/lread.c --- a/src/lread.c Thu Jul 10 23:37:52 2008 +0200 +++ b/src/lread.c Wed Jul 16 22:36:03 2008 +0200 ＠＠ -1855,6 +1855,28 ＠＠ break; } } + + if (count == 3) + { + c = readchar (readcharfun); + if ((c >= '0' && c <= '9') || + (c >= 'a' && c <= 'f') || + (c >= 'A' && c <= 'F')) + { + Lisp_Object args[2]; + + if (c >= '0' && c <= '9') i = (i << 4) + (c - '0'); + else if (c >= 'a' && c <= 'f') i = (i << 4) + (c - 'a') + 10; + else if (c >= 'A' && c <= 'F') i = (i << 4) + (c - 'A') + 10; + + args[0] = build_string ("?\\x%x"); + args[1] = make_int (i); + syntax_error ("Overlong hex character escape", + Fformat (2, args)); + } + unreadchar (readcharfun, c); + } + return i; } case 'U': -- ¿Dónde estará ahora mi sobrino Yoghurtu Nghé, que tuvo que huir precipitadamente de la aldea por culpa de la escasez de rinocerontes? _______________________________________________ XEmacs-Patches mailing list XEmacs-Patches(a)xemacs.org http://calypso.tux.org/cgi-bin/mailman/listinfo/xemacs-patches