Re: [exim] Is there a regex escape function?

On 02/10/12 11:24, John Horne wrote:

> I am trying to do a 'match' of one variable against another:
>
> ${if match {$h_X-UoP-Loop:} {^$sender_address } }
>
> The first variable is a space separated list of addresses, but in
> this instance we are checking if the list begins with the sender
> address and then a space.
>
> However, the sender address may well contain '.', which as a regex
> will match any character. So my question is whether there is any
> function to escape characters such as '.' so that they can then be
> used correctly in a regex?

In perl style regular expressions, \Q disables pattern meta-characters
until \E is reached. So try this:

${if match {$h_X-UoP-Loop:}{^\\Q$sender_address \\E}}

Proof that it works:

mike@ung:~$ exim -be '${if match{foo.bar}{^foo.bar}{true}{false}}'
true
mike@ung:~$ exim -be '${if match{fooXbar}{^foo.bar}{true}{false}}'
true
mike@ung:~$ exim -be '${if match{foo.bar}{^\\Qfoo.bar\\E}{true}{false}}'
true
mike@ung:~$ exim -be '${if match{fooXbar}{^\\Qfoo.bar\\E}{true}{false}}'
false
mike@ung:~$

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Mike Cardwell  https://grepular.com/     http://cardwellit.com/
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