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bug#31953: [VanL] Re: bug#31953: feature request - `highlight-rx` intera
From: |
Juri Linkov |
Subject: |
bug#31953: [VanL] Re: bug#31953: feature request - `highlight-rx` interactively |
Date: |
Tue, 22 Oct 2019 00:19:48 +0300 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (x86_64-pc-linux-gnu) |
>> - ‘or’ has a synonym ‘|’, but ‘and’ has no synonym ‘&’
>
> `and' is not the counterpart of `or', it's a synonym for `seq' or `:'.
> We should probably deprecate `and', since this is a bit confusing.
I consider ‘rx’ as an analogue of Definite Clause Grammar.
I'm so accustomed to Prolog paradigms used for defining grammars in DCG
that I can't use `rx' without its analogous constructs, e.g. such DCG:
rx --> a, b; c.
where ‘,’ denotes conjunction, and ‘;’ denotes disjunction,
would naturally translate in ‘rx’ to corresponding and/or:
(rx (| (& a b) c))
For example, this package parses a regexp and returns a DCG structure:
https://github.com/SWI-Prolog/packages-regex/blob/master/regex.dcg.pl