[REBOL] Re: [REBOL parse] Parsing AEIOU and sometimes Y
From: lmecir::mbox::vol::cz at: 2-May-2007 10:15
Hi Ed,
...
> A key piece of the algorithm requires counting the number ("measure")
> of vowel-consonant pair-sets according to the following pattern:
>
> [C] VC (m)... [V]
>
> Then the value of m is then used to apply suffix swapping rules. So...
> setting aside the "sometimes y" issue, the above can be expressed in
> 'parse as:
>
> rule: [any consonant [some vowel some consonant (m: m + 1)] any vowel]
>
> Once we introduce the "sometimes y" requirement, this simple rule
> becomes messy quickly. At the end of the day, I need to add up the
> [some vowel some consonant] rule under with that added "sometimes y"
> complexity. Thanks to your pointers, I think I'll be able to continue
> pursuing it in this direction, hopefully keeping the mess under
> control.
>
> Thanks,
> Ed
>
how about this one:
simple-vowel: charset "aeiouAEIOU"
simple-consonant: exclude charset [#"b" - #"x" #"z" #"B" - #"X" #"Z"]
simple-vowel
y: charset "yY"
pbc: first [
(
preceded-by-consonant: none
not-preceded-by-consonant: [end skip]
)
]
not-pbc: first [
(
preceded-by-consonant: [end skip]
not-preceded-by-consonant: none
)
]
vowel: [
[simple-vowel | preceded-by-consonant y (print "y = vowel")] not-pbc
]
consonant: [
[simple-consonant | not-preceded-by-consonant y (print "y consonant")] pbc
]
rule: [not-pbc any [consonant | vowel]]
-L
