For the precedenced rules, you create new symbols for each precedence, proceeding with associativity in the obvious way. Much of it is done in this routine: https://github.com/jeffreykegler/Marpa--R2/blob/master/cpan/lib/Marpa/R2/MetaAST.pm#L568
One thing to note is that it is *not* operator precedence -- the rule have precedence, and the operators play no special role. It's not dissimilar to rewrites you'll see elsewhere, but I might be its inventor, if only because nobody previously had a parser that could be expected to parse the rewritten rules. On Fri, Mar 6, 2015 at 11:22 AM, Andreas Kupries <andreas.kupr...@gmail.com> wrote: > > > On Thu, Mar 5, 2015 at 4:51 PM, Jeffrey Kegler > <jeffreykeg...@jeffreykegler.com> wrote: >> >> Quantified rules are semantic sugar for BNF, and you can write BNF rules >> and have access to all the symbols in them, including those you think of as >> separators. I say "think of", because if separators are given a semantics, >> they are (conceptually) more than just separators. Sequences can be written >> as recursions -- internally, that is what Marpa::R2 actually does. > > > Is there any documentation around on how Marpa::R2 rewrites the sugar into > basic BNF ? > > Ok, I know how it can be done for the quantified rules, via left recursion > and additional non-terminals. However for the priority rules I am still not > fully clear how these would be done. > > If there is no documentation, then is the rewrite engine in some > central/singular place in the sources, or is its activity distributed > through it, and where would I have to look ? > > > >> >> Use a left recursion, because that is easier on Marpa's internals. >> > > -- > You received this message because you are subscribed to the Google Groups > "marpa parser" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to marpa-parser+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "marpa parser" group. To unsubscribe from this group and stop receiving emails from it, send an email to marpa-parser+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
