[Nfsen-discuss] passing named parameters

[Kiss G. [Bitman] <ki...@ss...>]

Dear Peter,

I suggest to change the parameter passing of library routines like
NfSenRRD::SetupRRD.

Now caller have set up several trivial params in fixed order:
 	NfSenRRD::SetupRRD("$NfConf::PROFILESTATDIR/live", $new_source,
 		$tstart - 300, 0);

Now I plan to add Holt-Winters forecasting into RRDs and probably
I'd will have other developments. This may make some parameter lists
long and messy therefore easy to get it wrong.

Hash-line named parameters are more readable:

 	NfSenRRD::SetupRRD(
 		path	=>	"$NfConf::PROFILESTATDIR/live",
 		db	=>	$new_source,
 		start	=>	$tstart - 300,
# No 'force => 0' required because this is the default value
 		hw	=>	1,	# add Holt-Winters
 		alpha	=>	0.4,
# Other optional parameters here
 	);

Then function's head could look like this:

sub SetupRRD {
 	my %args = @_;
         my $path  = $args{path};
 	my $db    = $args{db};
 	my $start = $args{start};
 	my $hw    = $args{hw};		# undef (=false) if missing
 	my $force = $args{force};	# undef (=false) if missing
 	my $alpha = $args{alpha} || 0.3;
 	my $beta  = $args{beta}  || 0.002;
 	my $gamma = $args{gamma} || 0.05;

What is your opinion?

Regards

Gabor