[antlr-interest] Grammar from BNF

[Fabio Maulo]

Create a ANTLR lexer&grammar from a formal BNF like this 
http://savage.net.au/SQL/sql-2003-2.bnf , is a good or a bad idea ?
With a so grained lexer, how many slow will be the parser ?
Is it a good thing for token recognizer ?

Thanks.
Fabio.