Puppet users - Feb 2007 - newbie: logical AND, OR in selectors ?

Hello

Is it possible to construct selectors that can take into account two  
or more variables or conditions, by ANDing or ORing them together?

Eg, I am trying to write a cvsserve component which can optionally  
take a username (or connect anonymously) and can also optionally take  
a cvs tag name to export. So there would be four different  
combinations of cvs command to exec, eg:

cvs -d foohost.com:/cvsroot checkout barproject
cvs -d puppet@foohost.com:/cvsroot checkout barproject
cvs -d foohost.com:/cvsroot export -r REV1.1 barproject
cvs -d puppet@foohost.com:/cvsroot export -r REV1.1 barproject

The component definition would begin something like:

define cvsserve($source, $path, $user = undef, $rev = undef) {

And in psudo-code the component would do something like (being very  
simplistic here):

if (($user == undef) and ($rev == undef)) {
	$cvscmd = "cvs -d $source checkout $name"
}
if (($user != undef) and ($rev == undef) {
	$cvscmd = "cvs -d $user@$source checkout $name"
}
if (($user == undef) and ($rev != undef) {
	$cvscmd = "cvs -d $source export -r $rev $name"
}
if (($user != undef) and ($rev != undef) {
	$cvscmd = "cvs -d $user@$source export -r $rev $name"
}

Or are there other ways of achieving this? Perhaps:

$cvsroot = $user ? {
     undef => "$source",
     default => "$user@$source"
}
$cvsaction = $rev ? {
     undef => "checkout $name",
     default => "export -r $rev $name"
}
$cvscmd = "/usr/bin/cvs -d $cvsroot $cvsaction"

Actually, I think that may just work. Is this a sensible way to go? I  
guess it would still be useful to use AND and OR ...

Nb, I came up with this idea after looking at the svnserve example  
given in the Components section on the Language Structures page:

http://reductivelabs.com/trac/puppet/wiki/LanguageStructures#Components

Cheers
Jesse

> Is it possible to construct selectors that can take into account two  
> or more variables or conditions, by ANDing or ORing them together?
Afaik, puppet does not have boolean operators yet.  So:
> $cvsroot = $user ? {
>      undef => "$source",
>      default => "$user@$source"
> }
> $cvsaction = $rev ? {
>      undef => "checkout $name",
>      default => "export -r $rev $name"
> }
> $cvscmd = "/usr/bin/cvs -d $cvsroot $cvsaction"
> 
> Actually, I think that may just work. Is this a sensible way to go? I  
> guess it would still be useful to use AND and OR ...
is the way that the rest of us have been doing it for now.

--mac