port "activate instead"

[René J.V. Bertin]

Hi,

It's been a while that I miss a possibility to switch between foo and foo-devel ports without having to do the deactivation manually in a separate step. A normal `port activate foo` takes are automatically of deactivating the currently active version; how hard would it be to extend the activate syntax so it accepts an "instead of <port>" argument that would replace the "currently active" port to be deactivated?

Example:

%> sudo port activate --instead_of -f libVLC-devel libVLC at 2.2.1_0+dbus+qtkit+quartz+x11
(or --replace or --swap or some other more appropriate term)

instead of

%> sudo port deactivate -f libVLC-devel at 3.0.0-150503-g7385062d_0+dbus+qtkit+quartz+x11
%> sudo port activate libVLC at 2.2.1_0+dbus+qtkit+quartz+x11

The main reason for such a convenience feature is of course that the full specification of a port to be (de)activated is often an illegible expression that typically doesn't select entirely by double-clicking it.

R.