Here's what Jean wrote (with a lot more spacing to make it easier to see
what's going on):
[
Rebol []
a: {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
print "Parse 1"
parse/all a [
any [
[
[
thru {href="}
]
| [
thru {src="}
]
] copy text to {"} (
print text
)
]
]
probe a
print "Parse 2"
parse/all a [
any [
[
[
thru {href="}
]
| [
thru {src="}
]
] position1: to {"} position2: (
change/part position1 "neu" position2
print position2
)
]
]
probe a
print "Parse 3"
parse/all a [
any [
[
[
thru {href="}
]
| [
thru {src="}
]
] position1: to {"} position2: (
change/part position1 "neu" position2
print position1
print position2
print ""
)
]
]
probe a
halt
]
Jean wrote:
> It seems the parser is not at the right position after replacing the first
url.
That's sort of right. Have a look at the console printout:
Parse 1
http://www.ann.lu
http://bla.org
{assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
; Here's the second one coming up:
Parse 2
http://bla.org"; fdfdf
{assas href="neu" dfdfdf src="http://bla.org"; fdfdf}
Note that 'position2 seems to have printed out _too_ little information. At
first glance, it should have printed:
" dfdfdf src="http://bla.org"; fdfdf
Note that there 14 characters missing. Let's look at that 'change again:
change/part position1 "neu" position2
The difference in length between "neu" and "http://www.ann.lu"; is 14
characters. Clearly, when the 'change takes place, the 14 characters:
p://www.ann.lu
are removed from string value referred to by 'a. So that effectively
moves the place that 'position2 is refering to by 14 characters further
along.
Parse 3
neu" dfdfdf src="http://bla.org"; fdfdf
" dfdfdf src="http://bla.org"; fdfdf
neu" fdfdf
** Script Error: Out of range or past end
** Where: do-boot
** Near: print position2
print ""
Now when the value "http://bla.org"; is replaced with "neu" in the third
parse rule, the string is made another 11 characters shorter, so 'position2
"falls off the end of the string, and you get the error message:
** Script Error: Out of range or past end
To avoid this problem, readjust the position of 'position2. One can get the
new position as a result of the 'change function:
>> help change
USAGE:
CHANGE series value /part range /only /dup count
DESCRIPTION:
Changes a value in a series and returns the series after the change.
So your parse action (inside the paren!) will look something like:
position2: change/part position1 "neu" position2
and the parse rule (outside the paren!) will look something like:
] position1: to {"} position2: (
; blah blah blah...
) :position2 ; Here's where the position is reset.
I hope that helps!
Andrew Martin
ICQ: 26227169 http://valley.150m.com/
-><-
----- Original Message -----
From: "Holzammer, Jean" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, September 02, 2002 7:52 PM
Subject: [REBOL] replacing urls in html using parse function...
> Hi,
>
> I try to replace all href and src assignments in a html document by my own
> using the parse function.
>
> Here are my attempts (step by step) so far. Look at the one but last
> function call. It seems the parser is not at the right position after
> replacing the first url. I expected it to replace all (any keyword before
> rule) urls at once.
>
> I know there are lots of parsing experts on this list. Probably just some
> minor changes would be necessary.
>
> So have a look. Thanx in advance.
>
> Jean
>
>
>
> a: {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
> parse/all a [any [ [[thru {href="}] | [thru {src="}]] copy text to {"}
> (print text)]]
> parse/all a [any [ [[thru {href="}] | [thru {src="}]] position1: to {"}
> position2: (change/part position1 "neu" position2 print position2)]]
> parse/all a [any [ [[thru {href="}] | [thru {src="}]] position1: to {"}
> position2: (change/part position1 "neu" position2 print position1 print
> position2 print "")]]
>
> >> a: {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
> == {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
> >> parse/all a [any [ [[thru {href="}] | [thru {src="}]] copy text to {"}
> (print text)]]
> http://www.ann.lu
> http://bla.org
> == false
> >>
> >>
> >> a: {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
> == {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
> >> parse/all a [any [ [[thru {href="}] | [thru {src="}]] position1: to {"}
> position2: (change/part position1 "neu" position2 print position2)]]
> http://bla.org"; fdfdf
> == false
> >>
> >>
> >> a: {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
> == {assas href="http://www.ann.lu"; dfdfdf src="http://bla.org"; fdfdf}
> >> parse/all a [any [ [[thru {href="}] | [thru {src="}]] position1: to {"}
> position2: (change/part position1 "neu" position2 print position1 print
> position2
> print "")]]
> neu" dfdfdf src="http://bla.org"; fdfdf
> http://bla.org"; fdfdf
>
> == false
> >>
> >> a
> == {assas href="neu" dfdfdf src="http://bla.org"; fdfdf}
> >>
> >>
> >> parse/all a [any [ [[thru {href="}] | [thru {src="}]] position1: to {"}
> position2: (change/part position1 "neu" position2 print position1 print
> position2 prin
> t "")]]
> neu" dfdfdf src="http://bla.org"; fdfdf
> " dfdfdf src="http://bla.org"; fdfdf
>
> neu" fdfdf
> ** Script Error: Out of range or past end
> ** Where: halt-view
> ** Near: print position2 print ""
> >> a
> == {assas href="neu" dfdfdf src="neu" fdfdf}
> >>
> --
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