Relying on the fact that a given capturing group captured a null string
doesn't allow users to distinguish whether a capturing group did not
capture anything, or captured a null substring (say, from a null subject
string).
Perl allows for the distinction: the entries in the @- and @+ arrays are
set to values in case there is a capture, but they're undef otherwise.
PCRE2 gives us the information already in the results "ovector", but
it was simply not exposed to QREM users. So, expose it.
[ChangeLog][QtCore][QRegularExpressionMatch] Added the hasCaptured()
family of functions to know if a given capturing group has captured
something.
Change-Id: Ic1320933d4554e2e313c0a680be1b1b9dd95af0b
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>