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Postings from November 2000
>>>>> "SF" == Steve Fink <sfink@digital-integrity.com> writes: SF> Handling the parser's state can be done in a backtracking DFA-like or a SF> direct NFA-like way. The NFA way is to keep track of all possible parse SF> states and advance each one in parallel based on the next token. The DFA SF> way is recursive descent, backing out of blind alleys and trying again, SF> keeping a single working hypothesis alive at a time. The DFA approach is SF> probably easier to undo user code in, because in the NFA case you have SF> to consider each token under the assumptions of all possible parses up SF> to that point. The NFA case has the advantage that you never have to SF> back up, so you can permanently forget about a token as soon as it SF> whizzes by. Can an NFA actually handle the interaction between the lexer and tokenizer? $foo = s;foo;bar;g; $foo = s#foo#bar#g; # change the world <chaim> -- Chaim Frenkel Nonlinear Knowledge, Inc. chaimf@pobox.com +1-718-236-0183Thread Previous | Thread Next