[REBOL] Re: brainfart parse problem
From: gjones05:mail:orion at: 6-Jun-2001 16:59
Whoops forgot second example...
> > > From: "Erin Thomas"
> > > > >> rule: [thru "x" copy a [ opt to "y" | to "z"]]
> > > > == [thru "x" copy a [opt to "y" | to "z"]]
> > > > >> parse "x .... ab z cd y" rule
> > > > == false
> > > > >> a
> > > > == " .... ab z cd "
> > > >
> > > > now... how do i work the rule so it will stop at "z"
> > > > if "z" happens to be before "y"?
>
> > Ladislav Mecir wrote:
> > >
> > > valid: complement charset "xz"
> > > parse "x .... ab z cd y" [thru #"x" copy a [any valid] to end] ;
> true
> > > a ; == " .... ab "
>
> From: "Erin Thomas"
> > this is kind of what i want, but the "valid"s
> > aren't individual characters, they are a series
> > of characters, so doing a charset is out. how
> > would i get the same effect given that the "z"
> > and "y" were actually "zyx" and "yza"?
From: "Scott Jones"
> How about:
>
> a: copy ""
> rule: [
> thru "x"
> start:
> [to "z" | to "y"]
> ending:
> (a: copy/part start ending)
> to end
> ]
> parse/all "x .... ab zyx cd yza" rule
> print a ; yields: .... ab
Or also ;-):
a: copy ""
rule: [
thru "x"
copy a
[to "z" | to "y"]
to end
]
parse/all "x .... ab zyx cd yza" rule
print a
--Scott Jones
