autoconf: update to latest for fix of M4 detection.

[bison.git] / TODO

diff --git a/TODO b/TODO
index 216c97f4f84958ecc858ec691643720df010b76a..7f4c514898c84927621fc78cbf4db027012c41aa 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,6 +1,28 @@
 -*- outline -*-
 
 * Short term
+** Use syntax_error from the scanner?
+This would provide a means to raise syntax error from function called
+from the scanner.  Actually, there is no good solution to report a
+lexical error in general.  Usually they are kept at the scanner level
+only, ignoring the guilty token.  But that might not be the best bet,
+since we don't benefit from the syntactic error recovery.
+
+We still have the possibility to return an invalid token number, which
+does the trick.  But then the error message from the parser is poor
+(something like "unexpected $undefined").  Since the scanner probably
+already reported the error, we should directly enter error-recovery,
+without reporting the error message (i.e., YYERROR's semantics).
+
+Back to lalr1.cc (whose name is now quite unfortunate, since it also
+covers lr and ielr), if we support exceptions from yylex, should we
+propose a lexical_error in addition to syntax_error?  Should they have
+a common root, say parse_error?  Should syntax_error be renamed
+syntactic_error for consistency with lexical_error?
+
+** Variable names.
+What should we name `variant' and `lex_symbol'?
+
 ** Use b4_symbol in all the skeleton
 Then remove the older system, including the tables generated by
 output.c
@@ -433,6 +455,23 @@ to bison. If you're interested, I'll work on a patch.
 * Better graphics
 Equip the parser with a means to create the (visual) parse tree.
 
+* Complaint submessage indentation.
+We already have an implementation that works fairly well for named
+reference messages, but it would be nice to use it consistently for all
+submessages from Bison.  For example, the "previous definition"
+submessage or the list of correct values for a %define variable might
+look better with indentation.
+
+However, the current implementation makes the assumption that the
+location printed on the first line is not usually much shorter than the
+locations printed on the submessage lines that follow.  That assumption
+may not hold true as often for some kinds of submessages especially if
+we ever support multiple grammar files.
+
+Here's a proposal for how a new implementation might look:
+
+  http://lists.gnu.org/archive/html/bison-patches/2009-09/msg00086.html
+
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