Perl 6 - the future is here, just unevenly distributed

IRC log for #marpa, 2014-05-30

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All times shown according to UTC.

Time Nick Message
04:14 Aria "Gradual typing" ++
07:04 ronsavage joined #marpa
17:07 jeffreykegler joined #marpa
18:47 jeffreykegler At least 3 of you are working on Marpa clones in a higher level language, and I have a thought that might be on interest.
18:49 jeffreykegler There's a high cost in speed for using Ruby or Javascript, but the advantage of not using C is that experimentation is a lot easier -- and Marpa was in fact prototyped in Perl.
18:50 jeffreykegler An advantage claimed for left parsing, is the grammars can be extensible -- new symbols and rules can be added on the fly.
18:51 jeffreykegler As I've mentioned before, this is potentially very much possible with Marpa -- certainly not with its current implementation, which requires the grammar to be fixed before the parse starts, but Marpa could be extended to allow new rules and symbols.
18:52 jeffreykegler Those of you doing clones in higher-level languages might find this interesting.
18:53 jeffreykegler Note that this is one more reason to lose the LR(0) states, as was done in the last major rewrite of Marpa -- adding rules and symbols would mean updating the LR(0) tables, which is possible, but would be hard.
18:54 jeffreykegler Requirements would be to keep rules & symbols in an update-able form, and also be prepared to update all the pre-computations from the grammar ...
18:55 jeffreykegler As with left parsing, the new rules/symbols would only be effective going forward -- they would not be recognized in the input already read.
18:59 jeffreykegler Wrt speed, the effect should be small, and time complexity should remain the same, on the assumption that the maximum size of the grammar is treated as a constant.  The usual practice in analyzing parsers is to treat grammar size as O(1) -- constant.  If you're talking about the grammar growing in size with the input, that'd be a very different matter.
22:25 jeffreykegler joined #marpa
23:21 ronsavage Aria: "Gradual typing" ++: Some people would describe that as commitment-phobic!

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