[Haskell-cafe] conditionally exposing modules in cabal

I would like to conditionally expose a number of internal modules in a library depending on a cabal flag - the idea is that new features could be implemented externally to the library without contaminating the source with undesirable changes. However, I've been unable to find a way to structure a cabal file that does not require repeating the list of modules. For example, this works: exposed-modules: Public.Stable.Module if flag(exposeInternals) exposed-modules: <long list of internal modules> else other-modules: But I don't want to maintain two identical lists of modules in the cabal file. I've tried putting the section headers in the if's, but this doesn't appear to work (cabal doesn't complain, but the modules to be exposed are not available as expected): exposed-modules: Public.Stable.Module if flag(exposeInternals) { exposed-modules: } else { other-modules: } <long list of internal modules> Does anyone have suggestions? Thanks! Rogan