niksilver / elm-explained Goto Github PK

It would be nice to include some examples on Http requests and parsing the response.

I'm still getting my head around it. If I learn it properly I'll make a PR with an explanation of it. 😉

https://github.com/niksilver/elm-explained/blob/master/types/TypeQuestions.md#oddity-unused-variables

That's something you won't see in user code. The two modules you point to are "internal" modules of the Elm standard library, that come with native (JavaScript) implementations. That is, the Array and Signal types are implemented with JavaScript constructs that don't have a counterpart on the Elm side. The strange definitions you point out are just placeholders, so that the Elm compiler does not choke (it has to see something). So these are dirty tricks that are played in core, but that won't happen in pure Elm modules/packages. In fact, there were (are?) proposals for forbidding the presence of unused type variables in type definitions in "normal" modules.