-- Suggests a proof-script filename.
getProofScriptFileName :: String -> IO FilePath
getProofScriptFileName f = let fn = f <.> "hpf" in
  if isAbsolute fn then return fn else
     fmap (</> fn) getCurrentDirectory
getProofScriptFileName :: String -> IO FilePath
getProofScriptFileName f = let fn = f <.> "hpf" in
  if isAbsolute fn then return fn else
     fmap (</> fn) getCurrentDirectory
getProofScriptFileName f = let fn = f <.> "hpf" in
  if isAbsolute fn then return fn else
     fmap (</> fn) getCurrentDirectory