For #1807

I like the new syntax, thanks!

I'm pretty much rewriting it from scratch now. 😛
wrapLambdaM is so much nicer with a traversable functor of expressions.

Now that I'm building the tree earlier, I can't use Map - I need information about the order when processing the wildcards (they correspond to lambdas from left-to-right).

The parse error is bad when you have duplicate keys:

[1/1 ErrorParsingModule] src/Main.purs:8:14

  8  m = {foo: 0} {foo = 1, foo = 2}


  Unable to parse module:
  unexpected {
  expecting indentation at column 1 or end of input

In the parser I wrote an error saying "Duplicate key in record update: " ++ show key. But I'm not sure how to make it show that instead?

The parseUpdaterBody is behind a try at https://github.com/purescript/purescript/pull/2580/files#diff-476f52dcaa59ca2e52c4e867fda6a60fR441
I've tried moving the try inside parseUpdaterBodyFields before we build the tree, and it works for the first level, but not nested.

Ah ok. So solving this won't be trivial, but it's possible. We'd have to combine records and record updates into a single parser, I think.

I just tried to compile slamdata with the current master for benchmarking purposes and the parser fails on:

    collapse ∷ Card.Model → Array Card.Model → Maybe Card.Model
    collapse parent child = case parent, child of
      CM.Draftboard { layout }, [ cm@CM.Draftboard { layout: subLayout } ] → do
        cursor ← Pane.getCursorFor (Just deckId) layout
        layout' ← Pane.modifyAt (const subLayout) cursor layout
        pure $ CM.Draftboard { layout: layout' }

with:

[1/1 ErrorParsingModule] src/SlamData/Workspace/Eval/Persistence.purs:385:52

  385        CM.Draftboard { layout }, [ cm@CM.Draftboard { layout: subLayout } ] → do
                                                          
  Unable to parse module:
  unexpected {
  expecting ::, operator, , or ]

I guess it's related to the recent accessor chain parser changes? If it doesn't belong here lmk and I'll open a separate issue.

@kritzcreek would you also be able to try this with the latest commit in this pull request?

@LiamGoodacre Still get the same error with this branch.

@kritzcreek actually I think what you're seeing is related to #2559
This bit is causing the failure: cm@CM.Draftboard { layout: subLayout }

Thanks for the help cm@(CM.Draftboard { layout: subLayout }) fixes the compiler error! Might want to add that to a migration guide for the next release.

That seems like a bug, doesn't it? Parens aren't required like that for operator aliases.

@kritzcreek @natefaubion Could we move this conversation to either #2559 or a new issue, thanks :)