haskell/cabal — pull request #1550 by ryantrinkle (2013-10-18 05:29:04+00:00)
Title: Add support for 'main-is' to 'cabal init'

When a user uses 'cabal init' to set up an executable project, the result will not build, due to a missing 'main-is' directive. My suggestion is to prompt the user to enter a value for the 'main-is' field if they select "Executable" in response to "What does the package build".