No option for newlines with --cpp

[ag-eitilt]

I'd like to use the preprocessor to automate writing doctests for an Enum, and so obviously need the generated Haddock to span multiple lines. cpphs sounds like it's by far the best way to do so, with --layout. My workflow also dictates that I use cabal to start things building; because of how it constructs the ghc command, that then requires --cpp to be set. Unfortunately, doing so means that --layout gets ignored, and the Haddock gets clobbered to a single line. I feel I should note that occurs with any invocation of cpphs, not just via cabal.

That should be disappointing but not debilitating as newline replacements should work just fine, according to the documentation, but the \\n expansion never seems to work (and //n just deletes to the end of the definition). Am I missing something in how it should be invoked, or is there actually an issue?