This sounds like a job for anonymous subs:
my %constructor= {
MSWin32 => sub { FTP::Session::Win32->new( @_ ) },
HPUX => sub { FTP::Session::HPUX->new( @_ ) },
}
my $ctor= $constructor{$^O};
die "No constructor for $^O" if ! $ctor;
my $session= $ctor->( ... );
# Old Perl requires: $session= &$ctor( ... );
The next best thing is UNIVERSAL::can(),
which returns a reference to a named method. But then you
need to cache each class name so that you can pass that
in to the sub that you got a reference to:
my %class= {
MSWin32 => "FTP::Session::Win32",
HPUX => "FTP::Session::HPUX",
}
my %constructor= {
MSWin32 => FTP::Session::Win32->can("new"),
HPUX => FTP::Session::HPUX->can( "new" ),
}
my $ctor= $constructor{$^O};
die "No constructor for $^O" if ! $ctor;
my $session= $ctor->( $class{$^O}, ... );
# Old Perl requires: $session= &$ctor( $class{$^O}, ... );