instead of C, which a match
without the C<\G> anchor would have done. Also note that the final match
did not update C -- C is only updated on a C match. If the
final match did indeed match C, it's a good bet that you're running an
older (pre-5.6.0) Perl.
A useful idiom for C-like scanners is C. You can
combine several regexps like this to process a string part-by-part,
doing different actions depending on which regexp matched. Each
regexp tries to match where the previous one leaves off.
$_ = <<'EOL';
$url = URI::URL->new( "http://www/" ); die if $url eq "xXx";
EOL
LOOP:
{
print(" digits"), redo LOOP if /\G\d+\b[,.;]?\s*/gc;
print(" lowercase"), redo LOOP if /\G[a-z]+\b[,.;]?\s*/gc;
print(" UPPERCASE"), redo LOOP if /\G[A-Z]+\b[,.;]?\s*/gc;
print(" Capitalized"), redo LOOP if /\G[A-Z][a-z]+\b[,.;]?\s*/gc;
print(" MiXeD"), redo LOOP if /\G[A-Za-z]+\b[,.;]?\s*/gc;
print(" alphanumeric"), redo LOOP if /\G[A-Za-z0-9]+\b[,.;]?\s*/gc;
print(" line-noise"), redo LOOP if /\G[^A-Za-z0-9]+/gc;
print ". That's all!\n";
}
Here is the output (split into several lines):
line-noise lowercase line-noise lowercase UPPERCASE line-noise
UPPERCASE line-noise lowercase line-noise lowercase line-noise
lowercase lowercase line-noise lowercase lowercase line-noise
MiXeD line-noise. That's all!
=item ?PATTERN?
X
This is just like the C search, except that it matches only
once between calls to the reset() operator. This is a useful
optimization when you want to see only the first occurrence of
something in each file of a set of files, for instance. Only C
patterns local to the current package are reset.
while (<>) {
if (?^$?) {
# blank line between header and body
}
} continue {
reset if eof; # clear ?? status for next file
}
This usage is vaguely deprecated, which means it just might possibly
be removed in some distant future version of Perl, perhaps somewhere
around the year 2168.
=item s/PATTERN/REPLACEMENT/msixpogce
X X X X
X X