Add variation on `makeFree` without type signatures?

[ekmett]

Add variation on `makeFree` without type signatures?

[fizruk]

This makes perfect sense to me, I'd be happy to update TH module. Do you have a name for the command in mind? Or would it be better to pass options to makeFree?

[Gabriella439]

It's probably best not to change makeFree for backwards compatibility.

The issue with template haskell functions that take options is that in order to use them you have to apply them to their arguments in a separate module because of the stage restriction, so I wouldn't go down that route unless absolutely necessary. I'd be happy with just makeFree_ or makeFreeNoTypes.

[fizruk]

I think there might be one more nice command. We can introduce makeFreeCon for single constructors and prepend Haddock documentation to makeFreeCon invocation like this:

data LangF x
  = Input (String -> x)
  | Output String x
  | Halt
  deriving (Functor)

-- | Get string.
makeFreeCon 'Input

-- | Put string.
makeFreeCon 'Output

-- | Abort computation.
makeFreeCon 'Halt

This way one does not need to write down type signatures (which I find long and boring).

makeFree_ (and, perhaps, makeFreeCon_) would still make sense when one would like to comment individual arguments like this:

makeFreeCon_ 'Output

-- | Output.
output :: MonadFree LangF m =>
          String    -- ^ String to output.
          -> m ()   -- ^ No result.

[Gabriella439]

Yeah, I like that, too

[ekmett]

Merged