Re: Parsing Extensible Languages

johnl@ima.UUCP (Compilers moderator)
12 Apr 86 17:52:10 GMT

          From comp.compilers

Related articles
Parsing Extensible Languages johnl@ima.UUCP (1986-04-10)
Re: Parsing Extensible Languages johnl@ima.UUCP (1986-04-12)
Re: Parsing Extensible Languages johnl@ima.UUCP (1986-04-16)
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Posting-Version: version B 2.10.2 9/18/84; site ima.UUCP
From: johnl@ima.UUCP (Compilers moderator)
Newsgroups: mod.compilers
Date: 12 Apr 86 17:52:10 GMT
Article-I.D.: ima.192
Posted: Sat Apr 12 12:52:10 1986
Date-Received: 13 Apr 86 14:50:12 GMT
Organization: York U. Computer Science
Originally-from: decvax!mnetor!yetti!oz (Ozan Yigit)
In-Reply-To: <187@ima.UUCP>

In article <187@ima.UUCP> Rick Morrison writes:
>[are there any algorithms better than Earley's for parsing ambiguous
>context free languages?]


I think you should take a look at Thomas Cheatham's EL1. He may still be at
Harvard. EL1 is supposed to be a production-quality extensible-language.
His thesis explains the algorithms behind the compiler, and should be
available in a well-equipped university library. The compiler actually
exists, and to my [not so recent] memory, it is used.


oZ


Usenet: [decvax|allegra|linus|ihnp4]!utzoo!yetti!oz
Bitnet: oz@[yusol|yuyetti]
FREE SOFTWARE FOUNDATION vs. EMPIRE. Watch for
things to come..


[Good point -- I used EL1 in about 1975 and it was an interesting stab at
extensible languages. I still think that the O(N**3) limit will bite you,
though you might be able to find ways to distinguish the ambiguous and
non-ambiguous parts of your language and speed up parsing the non-ambiguous
stuff. -John]
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