Re: A minimal LL(1) parser generator ?

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From	anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups	comp.compilers
Subject	Re: A minimal LL(1) parser generator ?
Date	Sat, 25 Jan 2020 18:25:50 GMT
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carlglassberg@gmail.com writes:
>Anton, I now see that, in Gray, the precedence of "&&" is higher than every other operator.

Among the postfix operators, precedence is determined by the way they
are written down.  But yes, if you see (( a b || c d )) as having two
infix operators, || and the empty operator, then you can write a
precedence hierarchy:

postfix
empty
||

>So Gray EBNF:
>a b && c d && e f && <- x

Correctly written as

(( a b && c d && e f && )) <- x

>is equivalent to Wirth EBNF:
>
>x = a { b a } c { d c } e { f e } .

Yes.

>Likewise:
>
>a b && ? <- x

a b && ?? <- x

>is
>x = [ a { b a } ] .

Yes.

- anton
--
M. Anton Ertl
anton@mips.complang.tuwien.ac.at
http://www.complang.tuwien.ac.at/anton/

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A minimal LL(1) parser generator ? Andy <borucki.andrzej@gmail.com> - 2019-12-21 19:07 -0800
  Re: A minimal LL(1) parser generator ? arnold@skeeve.com (Aharon Robbins) - 2019-12-22 19:29 +0000
  Re: A minimal LL(1) parser generator ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2019-12-26 16:21 +0000
    Re: A minimal LL(1) parser generator ? carlglassberg@gmail.com - 2019-12-29 14:47 -0800
      Re: A minimal LL(1) parser generator ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2019-12-31 16:30 +0000
        Re: A minimal LL(1) parser generator ? carlglassberg@gmail.com - 2020-01-01 01:02 -0800
          Re: A minimal LL(1) parser generator ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2020-01-02 17:25 +0000
            Re: A minimal LL(1) parser generator ? carlglassberg@gmail.com - 2020-01-05 11:59 -0800
              Re: A minimal LL(1) parser generator ? carlglassberg@gmail.com - 2020-01-05 13:59 -0800
              Re: A minimal LL(1) parser generator ? carlglassberg@gmail.com - 2020-01-05 14:44 -0800
              Re: A minimal LL(1) parser generator ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2020-01-22 17:12 +0000
                Re: A minimal LL(1) parser generator ? carlglassberg@gmail.com - 2020-01-23 02:41 -0800
                Re: A minimal LL(1) parser generator ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2020-01-25 18:25 +0000
  Re: A minimal LL(1) parser generator ? gaztoast@gmail.com - 2019-12-31 07:10 -0800
  Re: A minimal LL(1) parser generator ? honey crisis <gaztoast@gmail.com> - 2020-01-02 08:50 -0800
  Re: A minimal LL(1) parser generator ? George Neuner <gneuner2@comcast.net> - 2020-01-02 13:16 -0500
  Re: A minimal LL(1) parser generator ? rockbrentwood@gmail.com - 2020-01-04 10:37 -0800
    Re: A minimal LL(1) parser generator ? honey crisis <gaztoast@gmail.com> - 2020-01-05 05:05 -0800
    Branched gotos was: Re: A minimal LL(1) parser generator ? Christopher F Clark <christopher.f.clark@compiler-resources.com> - 2020-01-06 08:47 +0200
      Re: Branched gotos was: Re: A minimal LL(1) parser generator ? Ben Hanson <jamin.hanson@googlemail.com> - 2020-01-07 11:32 -0800
    Re: A minimal LL(1) parser generator ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2020-01-22 17:08 +0000
      Re: A minimal LL(1) parser generator ? "Fred J. Scipione" <FredJScipione@alum.RPI.edu> - 2020-01-25 15:27 -0500

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