Em Sáb, 2009-09-26 às 16:14 +1000, Timothy S. Nelson escreveu: > I've been wondering about lenses recently. The page at > http://www.seas.upenn.edu/~harmony/ seems to give an overview, and I know > that > augeas also uses lenses. > It seems to me that a grammar can be thought of as a one-way lens. I > was wondering whether the bi-directional idea might be interesting in this > context. It seems to me that, at the moment, when we want to do a format > conversion, we: > - Read the data in with a grammar > - Output the data with something like Form.pm > I'm wondering if there isn't some way that the whole thing can be > turned into lenses. > Anyway, I'm sort of half thinking out loud, and wondered if anyone had > any relevant thoughts.
I think this is an interesting addition to the old "Tree Transforming Language" debate that once a year we remember to discuss. Basically, we could understand perl5+B::Deparse as composing a "lens", but it's done pretty much in an ad-hoc way, which is fine for perl5, since it's much more static (okay, that was before Devel::Declare)... But in Perl 6, that is pretty much interesting, because we have something pretty abstract, which is the STD parse tree, which needs to be converted into some implementation's optree/bytecode/whatever. but I'm sort of half thinking out loud as well ;) daniel
