runghc does not exist in versioned form
GHC provides several shell commands:
runhaskell, and possibly others.
ghc-pkg also have "versioned" forms—for instance, I also have available
runghc does not. This means I have no easy option when requiring a specific GHC version to run a Haskell file. This also means an executable Haskell file cannot easily express a dependency on a specific version of GHC, which may be useful in some cases.
Having to type
runghc -f which ghc-7.0.3`` is tedious overhead when doing this many times in a day. Furthermore, this does not appear to work at all with a shebang'd file.