I read about quotes etc from the same perldoc page (though I'd completely forgotten about /c and /o) and the fact that PCRE man.txt says nothing about them is kinda annoying. Unfortunately, this is information that should be known, because a quote-related issue appears in /filter -g. It is known that modifiers do not work in /filter. What is not so well known is that /filter seems to repeatedly strip out anything that looks like quotes from the pattern. Here's an example that should help:
Code:
alias filtertest {
  write -c ftest.txt $+(rc1,$crlf,rc2,$crlf,rc3)
  close -@ @@
  window -C @@ -1 -1 300 200
  if $1 == 1 { filter -fwg ftest.txt @@ /mim1rc1i/ }
  elseif $1 == 2 { filter -fwg ftest.txt @@ mim1rc1i }
}
The alias writes 3 lines of text in ftest.txt, first line is "rc1", second is "rc2, third is "rc3". /filtertest 1 grabs "rc3" and echoes it to the window @@, even though the pattern used is quite different. /filtertest 2 uses the second pattern and grabs "rc2" and "rc3". What mirc seems to do here is strip "m" and the quote characters from the pattern each time it checks a line of text. So, /filtertest 1 checks the 1st line, it strips the / / pair and the actual regex pattern is mim1rc1i. Moving on to the next line, it strips "mi" and the ending "i", so that the actual pattern is now m1rc1. Finally, it reaches the 3rd line, strips "m1" and "1" and makes the pattern rc, which of course matches "rc3". /filtertest 2 grabs "rc2" and "rc3" because it has one pair of quotes less (it lacks the / /'s), so the pattern becomes "rc" in the 2nd line instead of the 3rd.

/.timerQ 1 0 echo /.timerQ 1 0 $timer(Q).com