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Groups > comp.compilers > #1597
| From | federation2005@netzero.com |
|---|---|
| Newsgroups | comp.compilers |
| Subject | Re: lex - how to get current file position of parser file |
| Date | 2015-09-03 15:47 -0700 |
| Organization | Compilers Central |
| Message-ID | <15-09-002@comp.compilers> (permalink) |
| References | <15-08-019@comp.compilers> <15-09-001@comp.compilers> |
On Thursday, September 3, 2015 at 10:02:20 AM UTC-5, Kaz Kylheku wrote: > Another approach (if you can design the language that way) is to specify > reentrant parser and lexer. If you can get a clean unambiguous cut this should work. But it bears to point out that the reason you don't see reentrancy very much is that the LR framework is not really compatible with it. Lookaheads have to all be lined up, for a clean descent to a sub-level. This issue is what underlies the frequent-occurrence of the "advanced entry point" hack (e.g. starting up a sub-parser for "expressions" in a typical Algol language), where the sub-level starts up one or more tokens past the starting point of the thing being parsed. Those are the very things factored-out up front in an LR table. So you end up having to compromise on the LR-ness of LR itself, with the hack or similar means, if you want separate parser levels.
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lex - how to get current file position of parser file Jens Kallup <jkallup@web.de> - 2015-09-01 04:20 +0200
Re: lex - how to get current file position of parser file Kaz Kylheku <kaz@kylheku.com> - 2015-09-01 14:19 +0000
Re: lex - how to get current file position of parser file federation2005@netzero.com - 2015-09-03 15:47 -0700
Re: include files, was lex - how to get current file position of parser file Kaz Kylheku <kaz@kylheku.com> - 2015-09-04 05:26 +0000
Re: lex - how to get current file position of parser file Gene Wirchenko <genew@telus.net> - 2015-09-03 18:19 -0700
Re: lex - how to get current file position of parser file Jens Kallup <jkallup@web.de> - 2015-09-06 21:53 +0200
Re: lex - how to get current file position of parser file Kaz Kylheku <kaz@kylheku.com> - 2015-09-07 05:59 +0000
Re: lex - how to get current file position of parser file Jens Kallup <jkallup@web.de> - 2015-09-07 17:11 +0200
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