force install without a dependency

[Jacob Schwartz]

Is there a way to tell "port" to install a package (such as
"haskell-mode.el") without installing one of its dependencies (in this
case, "emacs")?  Since "emacs" is already installed on the Mac, it has
not been installed via MacPorts, so "port" doesn't know about it.
(And I can imagine other packages that are either pre-installed or
have been installed by hand.)  Further, in the case of the
Haskell-mode for "emacs", the dependencies on "emacs" and "ghc" should
really not be required for the install at all -- the dependencies are
only (conceivably) there because you're not going to use the
Haskell-mode unless you've also install "emacs" and "ghc" (although,
"ghc" is debatable, because you could have installed another Haskell
compiler/interpreter/other tool).

Right now, I'm just resigning to having MacPorts install emacs
(alternatively, I could have hand-installed the haskell mode, outside
of MacPorts).  But I'd like to know, for the future, if there's a way
to force "port" not to install certain dependencies.  (I see that
there is "-n" for upgrading, but in this case I don't want to prevent
upgrading of the dependency, I want to prevent installing.)

Thanks!

Jacob