paf31 / 24-days-of-purescript-2016 Goto Github PK

Day 4 has a link to http://try.purescript.org/?gist=ec91ebe17ca510f1ca36c8a535b292ac but that generates

No type class instance was found for

    Control.Monad.Error.Class.MonadThrow String
                                         (App
                                            ( console :: CONSOLE
                                            | eff4
                                            )
                                         )


while applying a function throwError
  of type MonadThrow t1 t2 => t1 -> t2 t3
  to argument "Out of range!"
while checking that expression throwError "Out of range!"
  has type t0 Unit
in value declaration example

where eff4 is a rigid type variable
        bound at line 24, column 1 - line 27, column 22
      t0 is an unknown type
      t1 is an unknown type
      t2 is an unknown type
      t3 is an unknown type

After: You can experiment with the other methods defined on the window object too.

https://pursuit.purescript.org/packages/purescript-dom/3.3.1/docs/DOM.HTML.Window#v:alert

From https://github.com/paf31/24-days-of-purescript-2016/blob/master/10.markdown#10-functional-dependencies

Prior to 0.10.3, we had no way to communicate this information to the type checker.

Should this be 0.10.1?

I'm posting this here since I'm unsure how gist notifications work and I don't know how to request a merge of a gist fork 🤷‍♂️. Please close it if it's the wrong place.

Just saw day 21, and it's great! As pointed out, the last example can't run since there's no lens for try ps. I forked @FrigoEU's gist and inlined the definitions and it seems to work: http://try.purescript.org/?gist=543c99d17de788c8be2e2d3a9b14d6c9.

@FrigoEU, are you up for taking the changes to your gist so we can see your example on try ps? If not, I can make a PR here to add the link to the post if that's acceptable.

@andyarvanitis, @balajirrao, @FrigoEU, @garyb, @kritzcreek, @LiamGoodacre, @nwolverson, @rightfold, @rvion

This year for "24 Days of PureScript", I'm going to be writing about new compiler features, and the list I have planned includes features you have worked on, so I'd like to invite you all to write a guest post about one or more of your features.

The posts will be short and very introductory. I'll typically show an example of each feature, and maybe talk about implementation too if it's simple and interesting enough.

If you're interested, please message me on Twitter. I'll lock this post to avoid spamming everyone. Thanks!