After some discussion with kevinfish in IRC, IMO the below will make things easier for people to follow what exactly the relevant error messages mean. APPROVE COMMIT NOTE: This patch has been committed. # HG changeset patch # User Aidan Kehoe <kehoea(a)parhasard.net&gt; # Date 1282413764 -3600 # Node ID 02d875ebd1ea4da4214e733f9a459dd508ddfc9d # Parent 04811a268716dbb77524e2ab2364a243a1c5c29c Make Lisp reader errors more informative with over-long hex, octal characters src/ChangeLog addition: 2010-08-21 Aidan Kehoe <kehoea(a)parhasard.net&gt; * lread.c (read_escape): Make error messages better reflect the text that was encountered, when overlong hex character escapes or non-Latin-1 octal character escapes are encountered. man/ChangeLog addition: 2010-08-21 Aidan Kehoe <kehoea(a)parhasard.net&gt; * lispref/objects.texi (Character Type): Go into more detail here on the specific type of error provoked on overlong hex character escapes and non-Latin-1 octal character escapes; give details of why the latter may be encountered, and what to do with such code. diff -r 04811a268716 -r 02d875ebd1ea man/ChangeLog --- a/man/ChangeLog Sun Aug 15 15:42:45 2010 +0100 +++ b/man/ChangeLog Sat Aug 21 19:02:44 2010 +0100 ＠＠ -1,3 +1,11 ＠＠ +2010-08-21 Aidan Kehoe <kehoea(a)parhasard.net&gt; + + * lispref/objects.texi (Character Type): + Go into more detail here on the specific type of error provoked on + overlong hex character escapes and non-Latin-1 octal character + escapes; give details of why the latter may be encountered, and + what to do with such code. + 2010-06-13 Stephen J. Turnbull <stephen(a)xemacs.org&gt; * external-widget.texi: Correct FSF address in permission notice. diff -r 04811a268716 -r 02d875ebd1ea man/lispref/objects.texi --- a/man/lispref/objects.texi Sun Aug 15 15:42:45 2010 +0100 +++ b/man/lispref/objects.texi Sat Aug 21 19:02:44 2010 +0100 ＠＠ -623,6 +623,8 ＠＠ ＠cindex backslash in character constant ＠cindex octal character code ＠cindex hexadecimal character code +＠cindex Overlong hex character escape +＠cindex Non-ISO-8859-1 octal character escape Finally, there are two read syntaxes involving character codes. It is not possible to represent multibyte or wide characters in this ＠＠ -643,14 +645,21 ＠＠ ＠samp{?\001} for the character ＠kbd{C-a}, and ＠code{?\002} for the character ＠kbd{C-b}. The reader will finalize the character and start reading the next token when a non-octal-digit is encountered or three -octal digits are read. +octal digits are read. When a given character code is above +＠code{#o377}, the Lisp reader signals an ＠code{invalid-read-syntax} +error. Such errors are typically provoked by code written for older +versions of GNU Emacs, where the absence of the #o octal syntax for +integers made the character syntax convenient for non-character +values. Those older versions of GNU Emacs are long obsolete, so +changing the code to use the #o integer escape is the best +solution. ＠pxref{Numbers}. The second consists of a question mark followed by a backslash, the character ＠samp{x}, and the character code in hexadecimal (up to two hexadecimal digits); thus, ＠samp{?\x41} for the character ＠kbd{A}, ＠samp{?\x1} for the character ＠kbd{C-a}, and ＠code{?\x2} for the character ＠kbd{C-b}. If more than two hexadecimal codes are given, the -reader signals an error. +reader signals an ＠code{invalid-read-syntax} error. ＠example ＠group diff -r 04811a268716 -r 02d875ebd1ea src/ChangeLog --- a/src/ChangeLog Sun Aug 15 15:42:45 2010 +0100 +++ b/src/ChangeLog Sat Aug 21 19:02:44 2010 +0100 ＠＠ -1,3 +1,10 ＠＠ +2010-08-21 Aidan Kehoe <kehoea(a)parhasard.net&gt; + + * lread.c (read_escape): + Make error messages better reflect the text that was encountered, + when overlong hex character escapes or non-Latin-1 octal character + escapes are encountered. + 2010-08-15 Aidan Kehoe <kehoea(a)parhasard.net&gt; * print.c (print_symbol): diff -r 04811a268716 -r 02d875ebd1ea src/lread.c --- a/src/lread.c Sun Aug 15 15:42:45 2010 +0100 +++ b/src/lread.c Sat Aug 21 19:02:44 2010 +0100 ＠＠ -1818,8 +1818,12 ＠＠ } } if (i >= 0400) - syntax_error ("Non-ISO-8859-1 character specified with octal escape", - make_int (i)); + { + read_syntax_error ((Ascbyte *) emacs_sprintf_malloc + (NULL, + "Non-ISO-8859-1 octal character escape, " + "?\\%.3o", i)); + } return i; } ＠＠ -1827,13 +1831,23 ＠＠ /* A hex escape, as in ANSI C, except that we only allow latin-1 characters to be read this way. What is "\x4e03" supposed to mean, anyways, if the internal representation is hidden? - This is also consistent with the treatment of octal escapes. */ + This is also consistent with the treatment of octal escapes. + + Note that we don't accept ?\XAB as specifying the character with + numeric value 171; it must be ?\xAB. */ { +#define OVERLONG_INFO "Overlong hex character escape, ?\\x" + REGISTER Ichar i = 0; REGISTER int count = 0; + Ascbyte seen[] = OVERLONG_INFO "\0\0\0\0\0"; + REGISTER Ascbyte *seenp = seen + sizeof (OVERLONG_INFO) - 1; + +#undef OVERLONG_INFO + while (++count <= 2) { - c = readchar (readcharfun); + c = readchar (readcharfun), *seenp = c, ++seenp; /* Remember, can't use isdigit(), isalpha() etc. on Ichars */ if (c >= '0' && c <= '9') i = (i << 4) + (c - '0'); else if (c >= 'a' && c <= 'f') i = (i << 4) + (c - 'a') + 10; ＠＠ -1847,21 +1861,12 ＠＠ if (count == 3) { - c = readchar (readcharfun); + c = readchar (readcharfun), *seenp = c, ++seenp; 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_ascstring ("?\\x%x"); - args[1] = make_int (i); - syntax_error ("Overlong hex character escape", - Fformat (2, args)); + read_syntax_error (seen); } unreadchar (readcharfun, c); } -- “Apart from the nine-banded armadillo, man is the only natural host of Mycobacterium leprae, although it can be grown in the footpads of mice.” -- Kumar & Clark, Clinical Medicine, summarising improbable leprosy research _______________________________________________ XEmacs-Patches mailing list XEmacs-Patches(a)xemacs.org http://calypso.tux.org/mailman/listinfo/xemacs-patches