[antlr-interest] Understanding priorities in lexing (newbie)
Gavin Lambert
antlr at mirality.co.nz
Fri Jul 13 01:21:55 PDT 2007
At 19:59 13/07/2007, Kay Roepke wrote:
>> In other words, the separation of lexer and parser is just
>> something that you have to accept and is unlikely to ever
>> change.
>
>Also, were the lexer dependent upon the parser you couldn't
store
>the tokens in an archive nor could you use a totally different
>lexer (e.g. a handwritten one, output from another lexer
generator).
>
>It's sometimes hard to draw the line between the two, especially
>for "weird" languages, where you sometimes feel the urge to
somehow
>direct the lexer from the parser, unfortunately. But keeping
them
>separate is a Good Thing(tm), IMHO.
Yep. Definitely.
(I kinda prefer V2's style a little in that regard, since it made
it more explicit that they were separate by not permitting
combined grammars, thereby removing some of the potential for
confusion. But once I figured out the whole
first-letter-uppercase bit I was happy with the V3 style
too. Though I tend to avoid using character literals in the
parser because I prefer getting nice token names ;))
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