[REBOL] Re: Parse problem
From: carl:cybercraft at: 9-Oct-2005 14:56
Hi Patrick,
I had a quick attempt at your problem when you first posted it, and have to agree, it's
not so easy. ;-)
I did expect someone to come up with a good method using PARSE though, and am surprised
they haven't. Anyway, I've had another go tonight and have worked out a method - one
that uses a recursive approach.
Essentially, to find the end of an URL, it looks for a space, return character or the
end of the file and copies from the URL start to there. Then, if it didn't find the
end of the file the copied text is itself parsed. This finds the URLs, but they may
of course have commas and so on attached to their ends. It's an easy matter to strip
them off though, giving you the true URL which you can then modify to replace the original.
So, here's the code: There's three parts to it - a parse rule where the recursion is
performed, a function to call it, strip any extra characters and replace the original
and the main parsing routing which calls the function...
str: {Hey go visit http://www.me.org, it's great! Or http://www.you.org
or http://www.them.org or even http://www.us.org!}
rule: [
some [
to "http://" copy text to " " (parse text rule) |
to "http://" copy text to "^/" (parse text rule) |
to "http://" copy text to end
]
]
modify: does [
parse text rule
;-- Add characters to the FIND string in the next line to increase
;-- the types of characters you need to remove from the end of an URL.
while [find {.,!)"} last text][remove back tail text]
new-text: rejoin [{<a href="} text {">} text </a>]
change/part s new-text length? text
s: skip s -1 + length? new-text
]
parse str [
some [
to "http://" s: copy text to " " (modify) :s |
to "http://" s: copy text to "^/" (modify) :s |
to "http://" s: copy text to end (modify) :s
]
to end
]
print str
Let me know if this behaves for you! :-)
I've just thought of one problem - if there's already an URL inside tags within the text,
it'd screw them up. So this isn't a universal solution. And it should really be made
into a nice, tide function.
-- Carl Read.
On Friday, 7-October-2005 at 14:19:52 Patrick Philipot wrote,
