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| From | "Ev. Drikos" <drikosev@gmail.com> |
| Newsgroups | comp.compilers |
| Subject | Re: About finding the start symbol of a grammar |
| Date | Sat, 22 May 2021 06:52:17 +0300 |
| Organization | Aioe.org NNTP Server |
| Lines | 15 |
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| Message-ID | <21-05-019@comp.compilers> (permalink) |
| References | <21-05-015@comp.compilers> |
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| Keywords | parse |
| Posted-Date | 22 May 2021 13:23:54 EDT |
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On 21/05/2021 13:49, Eduardo Costa wrote: > While there would exist grammars we could recursively check to find out which > it's start symbol is (i.e.: it's the only rule that used the rest of them, > where checking every other resulted in dangling rules that weren't even called > in), there might be other grammars for which more than one rule yields full > coverage (all of these obviously defining different languages) and so leading > to ambiguity. IMHO, it can be so simple as you describe here without important overhead. Typically, a parser will reduce the start symbol and finish. All rules that yield full coverage can be ie alternatives of a single root symbol: RootSymbol -> R1 | R2 | ... | Rn Ev. Drikos
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About finding the start symbol of a grammar Eduardo Costa <ecosta.tmp@gmail.com> - 2021-05-21 03:49 -0700
Re: About finding the start symbol of a grammar Kaz Kylheku <563-365-8930@kylheku.com> - 2021-05-21 14:14 +0000
Re: About finding the start symbol of a grammar anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2021-05-21 15:32 +0000
Re: About finding the start symbol of a grammar Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2021-05-21 17:02 +0200
Re: About finding the start symbol of a grammar "Ev. Drikos" <drikosev@gmail.com> - 2021-05-22 06:52 +0300
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