# Re: Dynamic Parsing..

## mauney@adm.csc.ncsu.edu (Jon Mauney)Wed, 15 Dec 1993 13:04:19 GMT

From comp.compilers

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Dynamic Parsing.. govin-k@cs.Buffalo.EDU (Kannan Govindarajan) (1993-12-14)
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 Newsgroups: comp.compilers From: mauney@adm.csc.ncsu.edu (Jon Mauney) Keywords: parse Organization: NCSU References: 93-12-058 Date: Wed, 15 Dec 1993 13:04:19 GMT

Kannan Govindarajan <govin-k@cs.Buffalo.EDU> writes:
>The problem I have is, given a grammar G, a string x such that x \in L(G),
>p(x,G) being the parse of x, and a string y such that x \approx y, I want
>to decide if y is in L(G), and construct the parse of y if y is in L(G).
>I want to do this without parsing y "from scratch". I want to just
>"modify" those portions of the parse of x which need to be changed to get the
>parse of y.

If you have the state of the parser at the point at which x and y differ,
you can pick up the parse from there. (That is, at the point at which
the first symbol of difference first appears in the lookahead.)

In the general case, you may need to re-parse to the end of the string.
You must put some significant restrictions on grammar or the edits
to limit the extent of parse changes.

The language-based editor researchers worked on this problem.
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Jon Mauney mauney@csc.ncsu.edu
Mauney Computer Consulting (919) 828-8053
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