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Re: [Marpa::R2] More Help With Grammar

by Jeffrey Kegler (Hermit)
on Nov 17, 2013 at 02:57 UTC ( #1062960=note: print w/replies, xml ) Need Help??


in reply to [Marpa::R2] More Help With Grammar

The problem you are having with multiple lines was caused by defining your file as only containing a single line. Here's what you need:

:default ::= action => [values] :start ::= Definitions :discard ~ ws Definitions ::= Definition + Definition ::= Alias <new line>

As for the backslash'd newlines, to treat them as horizontal space, you want something like:

ws ~ <ws element> + <ws element> ~ [\s] <ws element> ~ backslash [\n] <backslash> ~ '\'

I did test both of these with your multi-line example and they seem to work. The Sudoer's format is newline-sensitive -- it treats horizontal and vertical whitespace differently. You'll probably need to nail down exactly where newlines are OK according to the spec, before you're 100% compliant. Marpa has a mailing list, btw, where expert users hang out. Several of the people on the group have more experience with parsers for this kind of file than I have. You might consider joining up.

I hope this helps.

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Re^2: [Marpa::R2] More Help With Grammar (ABNF to Marpa/SLIF)
by Anonymous Monk on Nov 17, 2013 at 03:21 UTC

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[ambrus]: erix: that one actually sucks. these days people should get rid of the old notion that TeX is the only thing you can use for decent mathematics writing, because MS Office and LibreOffice have reached the
[ambrus]: level where people can more easily write as good mathematical papers in them as the people who write bad LaTeX papers usually write.
[ambrus]: Yes, for like the first twenty of its years, TeX was basically the only system that allowed you to write decent maths papers, and C++ and PHP were programming languages that sucked, etc. But times change and people have to accept that.
Discipulus bad people + good tool < normal people + decent tool
[Discipulus]: php does not suck anymore?
[ambrus]: Discipulus: I'm not sure, but it certainly doesn't suck as much as it's used to. it's like C++, it sucks because people still recursively learn from twenty year old PHP examples,
[ambrus]: and they try to use the obsolete features that PHP has to support only for compatibility with old scripts. C++ and PHP both have the problem that people can't forget the past, because when they google "PHP" plus the problme they want to solve, they find b
[ambrus]: ad code examples.
[ambrus]: I'm not trying to recommend PHP, but I think it has way too bad a name because of its past.
[ambrus]: This is different from MS Word, which was already a good editor in the pre-unicode days (in word for windows versions 2 and 6, which ran on windows 3 but also on windows 95), only it wasn't trying to solve the task of writing maths papers back then.

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