You might look at Ron Savage's recent code and writings -- his new modules are heavily event-driven, and he's written an article on one of them: http://savage.net.au/Ron/html/Fancy.Matching.of.Delimited.Text.html
On Thu, Jan 8, 2015 at 11:25 AM, Zeev Atlas <zatl...@gmail.com> wrote: > The most important case that I have in mind is the SQL Server 'SELECT TOP > 5 col1, col2, ...'. Wouldn't the Pre-lexeme event be better then the > Rejection in that particular case? I am reading the documentation as is > written now [ > http://search.cpan.org/~jkegl/Marpa-R2-2.101_000/pod/Event.pod#The_life_cycle_of_events]. > The events and their use is not always clear from the documentation. > You've mentioned that what I want to achieve could be done in various ways > and I assume that you meant by judicious use of the events. I need a bit > of help here, like better, less formal and more example oriented > explanation of the events. > Thank you > ZA > > > On Wednesday, December 31, 2014 12:24:58 PM UTC-5, Jeffrey Kegler wrote: > >> Zeev -- the sort of thing you suggest can be done, in various ways. You >> can pause the parse, switch to manual parsing, and resume the input at an >> input location of your choice. >> >> As an example of this sort of thing, I recently did my own example of >> delimiter handling >> <http://jeffreykegler.github.io/Ocean-of-Awareness-blog/individual/2014/11/delimiter.html> >> which, when it encounters a missing delimiter, supplies it. >> >> The reason I think you see the others (and myself) preferring a direct, >> rule-based, approach is that it makes for simpler, faster and more >> maintainable code, when it is possible. And what with the wide variety of >> grammars that Marpa can parse, plus various tricks such as ranking rules, >> it often is possible. >> >> On Wed, Dec 31, 2014 at 4:37 AM, Zeev Atlas <zat...@gmail.com> wrote: >> >>> As I read more and begin to grasp the complexity of Marpa solution, and >>> the desire to work all issues from within the context of grammar, actions >>> (evemts, etc.) I can see why you guys want to insist on using rules and >>> only rules, whether positive or negative, to parse the subject. Let me >>> please givee you a counter argument: >>> I am not a native English speaker. When I learned the language, till >>> today, when reading and parsing text, i may and do encounter words that I >>> do not know. Instead of going to the dictionary, I encapsulate such words >>> and substitite them with either a context based approximation or with null >>> and try to continue parsing. Rarely, indeed very rarely, I cannot proceed. >>> What I would want is something similar, in which Marpa would tell me >>> that it have encountered such an element and allow me to advise it to >>> substitute it with something else or nullify it and continue. >>> I do not know how hard is that to implement, but I suspect that it >>> should not be that hard. And the practical benefits would be enormous >>> ZA >>> >>> -- >>> 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...@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. > -- 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.
