extractPTermNames :: PTerm  -- ^ Where to extract names from
                  -> [Name] -- ^ Extracted names
extractPTermNames (PRef _ _ n)       = [n]
extractPTermNames :: PTerm  -- ^ Where to extract names from
                  -> [Name]
extractPTermNames (PRef _ _ n)       = [n]
extractPTermNames (PRef _ _ n)       = [n]