print "($1)($2)\n"
    while  "fFFggGGGG" =~ /([a-z]+)\U(\1*)/g;
print "---\n";
print "($1)($2)\n"
    while  "fFFggGGGG" =~ /([a-z]+)\U(\1*g)/g;
__END__
Prints:
(f)()
(gg)()
---
(gg)(G)