The -main-is option to runghc does not appear to work.
The -main-is option to runghc does not appear to work, at least not when specifying a package name. Create Hello.hs:
module Hello where
main = putStrLn "Hello."
and then try to run it:
runghc -main-is Hello Hello.hs
You will see:
<interactive>:1:113:
Failed to load interface for `Main':
Use -v to see a list of the files searched for.