The ShareStream constructor is wrong about purescript-node-child-process

[paf31]

What about

data StdIOBehaviour r eff = ShareStream (Stream r eff) | [...]

and then specifying r depending on the particular stream (stdin etc.) and propagating eff to the FFI definitions which use the options object?

[hdgarrood]

I can't see how to make that work well, because different StdIOBehaviour values corresponding to different streams all have to go into an array together, and often these different streams have different values for r (in particular, stdin, stdout, and stderr often appear there together); relevant docs: https://nodejs.org/dist/latest-v6.x/docs/api/child_process.html#child_process_options_stdio

I'm not all that keen on propagating effect rows here either, because then you'd have to make sure they line up when you use spawn and that might be a pain, but also if you're creating child processes the compiler isn't going to be able to tell you what effects that might cause, so I'm not sure effect tracking is going to pay off here.

[paf31]

On the array side, you could replace it with a record, since there are always three things in the array, right?

[hdgarrood]

I don't think there necessarily are, at least node seems to happily spawn things if I specify stdio: [] or stdio: ['pipe']. Although perhaps leaving them out is the same as passing null, so I'd guess [] means the same as [null,null,null] and ['pipe'] means the same as ['pipe',null,null]. There are sometimes more than three things in the array, too.

[hdgarrood]

Effect simplifies this :)

[JordanMartinez]

This has been resolved in the new way of handling stdio via the safe ChildProcess and the unsafe UnsafeChildProcess.