[antlr-interest] ANTLR should warn about nullable tokens
David Piepgrass
qwertie256 at gmail.com
Mon Jun 25 16:44:03 PDT 2007
I was testing my lexer on an invalid input when it entered an infinite loop.
It turns out this was because of my whitepace rule:
WS: (' '|'\t'|'\n'|'\r'|'\u000C')* { $channel=HIDDEN; };
Which caused an infinite sequence of WS tokens. It should be
WS: (' '|'\t'|'\n'|'\r'|'\u000C')+ { $channel=HIDDEN; };
IMO, ANTLR should give a warning about this.
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