Sounds like you are using ANTLRWorks? They are reported, but they don't thrown exceptions.
Jim > -----Original Message----- > From: [email protected] [mailto:antlr-interest- > [email protected]] On Behalf Of Kevin Carroll > Sent: Friday, May 28, 2010 12:49 PM > To: [email protected] > Subject: [antlr-interest] "Missing" Tokens Do Not Cause Errors > > Here are a couple of simple rules extracted from a combined grammar I > have: > > RETURNS : ('R'|'r')'eturns' > { $text = "RETURNS"; } ; > > returnsStatement > : RETURNS ':' type ';' -> > ^(RETURNS type) > ; > > (type's definition is, I think, irrelevant. It matches the typical > things - int, double, etc.). > > Note that the rule uses the rewrite syntax and omits the ':' and ';' > tokens in the AST. > > I am observing that my parser accepts inputs even when these tokens are > missing. > > For example, the line: "returns double" is accepted (note, no ':' or > ';'). In stepping through the parse, the Match() method calls that > should match the ':' and ';' return '<missing ':'>' and '<missing > ';'>', respectively, yet do not fail. I understand that a feature of > ANTLR is that missing tokens are sometimes automatically inserted to > allow the parse to proceed, but shouldn't the erroneous line(s) be > reported? > > Is this behavior correct and/or expected? If not, does anyone have any > clues as to what might be going wrong? > > Thanks, > Kevin Carroll > > > List: http://www.antlr.org/mailman/listinfo/antlr-interest > Unsubscribe: http://www.antlr.org/mailman/options/antlr-interest/your- > email-address List: http://www.antlr.org/mailman/listinfo/antlr-interest Unsubscribe: http://www.antlr.org/mailman/options/antlr-interest/your-email-address -- You received this message because you are subscribed to the Google Groups "il-antlr-interest" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/il-antlr-interest?hl=en.
