Re: LL Parsing (VBDis)
22 Oct 2000 01:31:33 -0400

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From: (VBDis)
Newsgroups: comp.compilers
Date: 22 Oct 2000 01:31:33 -0400
Organization: AOL Bertelsmann Online GmbH & Co. KG
References: 00-10-138
Keywords: parse, comment

"R. Anthony Vestal" <> schreibt:

>Is there a class of applications that benefit by top-down parsing?

IMO *every* application will benefit from top-down parsing. A parser
usually will not only interpret some source code in the context of
some grammar, but shall execute some actions, whenever something
what-requires-action is recognized. In a top-down (procedural)
approach the expected context is quite clear, in contrast to the
context in a bottom-up state machine.

Perhaps I'm wrong with this opinion, but I also like to learn more
about bottom-up and top-down parsing in practice.

Perhaps a mix of both approaches might be the best solution, resulting
in compact code when a state machine can be used, and with other
benefits when a procedural approach is used for other parts of the

[The original Ritchie C compiler used top-down recursive descent for most
of the parsing, but bottom-up operator precedence for expressions. -John]

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