-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 apfelmus wrote:
Mark T.B. Carroll wrote:
I've been playing with Text.Parsers.Frisby to see how it stacks against other options and, while it's been great so far, I am finding that I can't encode a grammar where what's acceptable depends on what's already been parsed in some nontrivial way. [...] Is this supposed to not be possible in Frisby, or (quite likely) am I missing something that allows me to?
It's intentionally impossible. Frisby uses a dynamic programming approach that crucially depends on the fact that the grammar in question is context-free (actually something related, but the effect is the same).
Is that dependence crucial? What if it gained Monad operations that just weren't intended to be used very often, and maybe locally harmed performance a little where they are used? BTW: (P s) should be an instance of Applicative (which is already possible with Frisby's current code, just not there) (I prefer the aesthetics of Frisby-applicative code to many of the combinators it provides - I tried it a little sometime, not enough to send a darcs patch) Isaac -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGXFZVHgcxvIWYTTURApl+AKClt8J1m+qkEG+qNSI4RSATmZfSkACfdJN8 4gLKaM/hKS85UgMsERoItRM= =dJx9 -----END PGP SIGNATURE-----