#ok, with a weird example of $1
@result = grep{ print "$1 $_\n" if /^..(A|B)./;
                /^..(A|B)./}@x;
                
=prints
B aaBxyz
B ..Bxys
A xxAx
=cut
@result is the same as above

# grep {} executes the code within the brackets and passes the input
# to @result depending upon the true/false value of the last statement.