[RegExp] Making non-greedy; Escaping parentheses?

[Jane Doe]

Hello,

I need to browse a list of hyperlinks, each followed by an
author, and remove the links only for certain authors.

1. I searched the archives on Google, but didn't find how to tell the
RegExp object to be non-greedy as using the ? quantifier doesn't seem
to work.

--------- SAMPLE ----------------
var items = new Array("johndoe" ,"janedoe"
// Add parentheses to match any item in items()
var list = '('
list += items.join("|")
list += ')'

//Example: <A href="dummy.php ?page=10#934569 ">TITLE
</A>, AUTHOR, April 12, 2003<br>

pattern = '<A href=".+?#[0-9]+?">.+?</A>, '
pattern += list
pattern += ',.+?<br>'

var input = new RegExp(temp,"gi ");
var output = 'TROLL<br>'
document.body.i nnerHTML = body.replace(in put,output);
--------- SAMPLE ----------------

Does somebody know how to do this?

2. Also, I notice that when using (johndoe|janedo e) in a pattern, the
value is copied into one of the $x variables. In this particular case,
I don't need this.
Is there a way to escape parentheses to tell RegEx _not_ to put this
item into a variable? I tried "\(" and "((", to no avail.

Thank you very much for any help
JD.

[Martin Honnen]

Re: [RegExp] Making non-greedy; Escaping parentheses?



Jane Doe wrote:

[color=blue]
>
> 2. Also, I notice that when using (johndoe|janedo e) in a pattern, the
> value is copied into one of the $x variables. In this particular case,
> I don't need this.
> Is there a way to escape parentheses to tell RegEx _not_ to put this
> item into a variable? I tried "\(" and "((", to no avail.
>[/color]

I think you are looking for non-capturing parentheses e.g.
/(?:john|jane)do e/
but that is only supported with IE5.5+ and Netscape 6+

--

Martin Honnen

http://JavaScript.FAQTs.com/

[Lasse Reichstein Nielsen]

Re: [RegExp] Making non-greedy; Escaping parentheses?

Jane Doe <jane.doe@acme. com> writes:
[color=blue]
> I need to browse a list of hyperlinks, each followed by an
> author, and remove the links only for certain authors.
>
> 1. I searched the archives on Google, but didn't find how to tell the
> RegExp object to be non-greedy as using the ? quantifier doesn't seem
> to work.[/color]

It should, if the browser is sufficiently new. The improved regular
expressions (non-greedy +,*,? and {}, non capturing bracketsa and
lookahead) are part of Javascript 1.5 and ECMAScript, not the eariler
Javascript versions.
[color=blue]
> --------- SAMPLE ----------------
> var items = new Array("johndoe" ,"janedoe"[/color]

Missing end parenthesis (and semicolon! Always end your sentences
with a semicolon.).
[color=blue]
> // Add parentheses to match any item in items()
> var list = '('
> list += items.join("|")
> list += ')'
>
> //Example: <A href="dummy.php ?page=10#934569 ">TITLE
> </A>, AUTHOR, April 12, 2003<br>[/color]

Is the entire string always on one line?
As a stupid convention, the regular expression "." matches
all non-EOL characters, but there is no shorthand for matching
any character. If the text contains newlines, you may need to
change "." to, e.g., "[\s\S]".
[color=blue]
> pattern = '<A href=".+?#[0-9]+?">.+?</A>, '
> pattern += list
> pattern += ',.+?<br>'[/color]

If your code is inside a script tag, and not in an external file,
you should escape your "</"'s as "<\/". Most browsers are forgiving.
[color=blue]
> var input = new RegExp(temp,"gi ");[/color]

Do you mean "pattern" instead of "temp"?
[color=blue]
> var output = 'TROLL<br>'
> document.body.i nnerHTML = body.replace(in put,output);
> --------- SAMPLE ----------------
>
> Does somebody know how to do this?[/color]

One problem is, that a minimal match will still be as early as possible.
If you have two entries in a row, and the second has an author on your
hit-list, it will find a match starting at the first "<A". It finds
the minimal match starting there, which includes both entries, so
both are replaced.
To avoid this, you can restrict the .'s so they can't match too far:

pattern = '<A href="[^"]+?#\\d+?">[^<]+?</A>, ';
pattern += list;
pattern += ',[^>]+?<br>';

This prevents matching further than we want it. If there are tags
inside the TITLE or in the date after the author name, then "[^<]"
isn't sufficient as a restriction.
[color=blue]
> 2. Also, I notice that when using (johndoe|janedo e) in a pattern, the
> value is copied into one of the $x variables. In this particular case,
> I don't need this.
> Is there a way to escape parentheses to tell RegEx _not_ to put this
> item into a variable? I tried "\(" and "((", to no avail.[/color]

Yes.
(?: ... )
This pair of parentheses are purely grouping, and the match won't be
remembered.

/L
--
Lasse Reichstein Nielsen - lrn@hotpop.com
Art D'HTML: <URL:http://www.infimum.dk/HTML/randomArtSplit. html>
'Faith without judgement merely degrades the spirit divine.'

[Jane Doe]

Re: [RegExp] Making non-greedy; Escaping parentheses?

On 12 Sep 2003 18:35:18 +0200, Lasse Reichstein Nielsen
<lrn@hotpop.com > wrote:[color=blue]
>It should, if the browser is sufficiently new. The improved regular
>expressions (non-greedy +,*,? and {}, non capturing bracketsa and
>lookahead) are part of Javascript 1.5 and ECMAScript, not the eariler
>Javascript versions.[/color]

Thank you very much Martin and Lasse :-) Finally got it working thanks
to you. I didn't know non-greedy regexes were so recent in JS.

Thanks again
JD.