[Exim] Sata^H^Hnatizing strings in exim filter?

Hi,

Is there, or will there be, the possibility to 'sanatize' strings
matched from headers in userland exim filters?

Say, for example, I want to do something like the following, and I
want (need...) to filter out characters like [.<>?/* ] for security
reasons:

| if $h_From: matches "([^@])@" then
|     save mail/saved/by/sender/localpart/$1
|     finish
| endif

Is it possible? I couldn't find anything relevant on exim.org.
Will it be possible?
- Maybe if I am able to create a patch that implements this? :)

Kind regards,
Sander.
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