On Sun, 22 Dec 2002, Marc Perkel wrote:
> OK - I'm getting close here. The following expression works perfectly when
> tested with exim -be
>
> ${sg\
> {${sg\
> {${readfile{/etc/exim/blockfrom}{|}}}\
> {\\|*#end.*|#.*?\\|}\
> {}\
> }}\
> {(\\|)\\|}\
> {$1}\
> }
>
> but - when I try this: in a filter:
>
> if "$h_from:" mateches "${sg\
> {${sg\
> {${readfile{/etc/exim/blockfrom}{|}}}\
> {\\|*#end.*|#.*?\\|}\
> {}\
> }}\
> {(\\|)\\|}\
> {$1}\
> }"
>
> It complains about regular expression errors. I did read that extra \\ are
> neaded, but I don't know how many and where.
>
> What characters in the above expression need extra \ and how many?
When you put something into quotes you need to put one extra \ in front
of every \ in the original, except the \ that are used for line
continuation. The order of processing is:
1. Line continuation - backslashes at the ends of lines are removed, and
lines are joined together.
2. String processing - strings in double quotes are processed for escape
sequences starting with \.
3. String expansion - backslashes are again an escape character.
4. Regex matching - backslashes are interpreted according to the
syntax of regular expressions.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
