Question

Can some one please explain me the following expression

$input =~ m/\G".*?"(,|$)/gc || $input =~ m/\G[^,]*(,|$)/gc || die;

Answer 1

There are two regexes here. The first is:

\G    # the end of the previous match
".*?" # something in quotes
(,|$) # and a comma, or the end of the string

The second will be matched if the first one fails:

\G    # the end of the previous match
[^,]* # anything up to the next comma or end of string
(,|$) # and then a comma, or the end of the string

My guess is the two regexes are designed to match something which can either be quoted or not quoted, and may be followed by some more items after a comma.

(The c modifier means to keep the current position if the matching fails, so the \G anchor won’t change in the second attempt to match if the first one fails. The g modifier sets the position for \G for the next match – among other things.)