[REBOL] Re: 'Parse is peculiar! - more details
From: ingo:2b1 at: 15-Dec-2000 8:19
Hi Brett,
found an error in my last post, it didn't work for "<<"
line1: {Lets find "Ju<<<l>ie<1234><WON:90966776>"}
main-rule: [ (next-part: "") thru {"} copy name to {<} some sub-rule to end ]
sub-rule: [ "<WON:" (print name) to end
| (if next-part <> "" [if none? next-part [next-part: ""] append name join "<" next-part]
)
skip copy next-part to "<" ]
>> parse line1 main-rule
Ju<<<l>i
(if "<" are directly following each other, name-part is set to none,
so I have to change to "")
kind regards,
Ingo
Once upon a time Ingo Hohmann spoketh thus:
> Hi Brett,
>
> here's my take, assuming that "<WON:" is sure not to be in the name-string
> (and it is the only thing you can be sure about ...
>
> line1: {Lets find "Ju<l>ie<97868769><1234><WON:90966776>"}
> main-rule: [ (next-part: "") thru {"} copy name to {<} some sub-rule to end ]
> sub-rule: [ "<WON:" (print name) to end
> | (if next-part <> "" [append name join "<" next-part] ) skip copy next-part
to "<" ]
>
> >> parse line1 main-rule
> Ju<l>i<97868769>
>
> OK, what do I do?
>
> in main-rule first create an empty-string next-part (no copy needed, as the
> string is not changed, the word gets assigned to new strings later on)
>
> Up to copy name it's the same as before, but then we go into the sub-rule.
>
> when entering sub-rule we are right before the "<" so we can test if it is
> "<WON:" by chance, if it is, w're done, print the name, and go to the end.
>
> If it's not "<WON:" we first test if next-part is still "" (first pass) and
> we either do nothing, or append a "<" and next-part to the name", then we
> skip over the "<" (remember? that's where we entered the sub-rule!) and then
> we copy the next-part of the name to the next "<" the rule ends here, but
> we've told parse to check this rule multiple times (some), so we just reenter
> the sub-rule ...
>
> I hope this helps,
>
> Ingo
>
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