Portfile for a virtual port?

[Mike O'Brien]

	We need to construct a virtual port.  We wish to allow our users to have one-click installation access to a coterie of ports in MacPorts, between six and twenty of them which are constituent ports making up an open-source Matlab replacement called Python(x,y).  There is no current metaport for this, and no instructions on how to make one, though it is trivially easy (thank you!) to construct a metapackage for a single port and all of its dependencies.

	What I'm looking to construct is a port which itself installs nothing, but whose dependencies cause all of the constituent ports comprising Python(x,y) to be installed.  Then I can make a metapackage for that port, and distribute the resulting ".mpkg" file to our users.

	Is there an accepted, canonical way to do this?  The trivial way to do it would be to null out all the parts of a portfile, except the "devroot" (install) section is not allowed to be null.

Mike O'Brien