Arrow functions and parentheticals on their own line

[edemaine]

The following input transpiles to itself:

x
(z) => z

But JavaScript has trouble with it, trying to parse it as a function call x(z) and then failing with SyntaxError: Malformed arrow function parameter list.

Perhaps even grosser is that the following gets treated like a function call, but I don't think it should.

x
(z)

Perhaps we can automatically add semicolons in these cases?

[STRd6]

A simple-ish fix would be to add a look-ahead in StatementDelimiter like:

&( Samedent "(" ) -> ";"

Before the &EOS rule.

[STRd6]

Probably create and use an InsertSemicolon rule to keep token and location info.

[edemaine]

This approach works pretty well, though there are some issues:

• If we end up adding an implicit return to the following statement, we don't need to have added a semicolon. (No harm done though.)
• I worry about code like this which would end up adding parens that weren't in the input:

  x
  {y: z} = obj

  This code has a different problem right now though. (Function call without indentation #273)

For the second issue in particular, I wonder about doing this in a second pass. Maybe a processBlocks? Let me know what you think.

[STRd6]

Good points. Maybe it would make more sense to do this in processBlocks. I've also been thinking about doing even more processing later in the AST. We may even be able to have it handle expressionizing everything as well.

[STRd6]

If we want a quick hacky solution for the meantime:

&( Samedent ( "(" / "{" / "[" ) ) -> ";"

[edemaine]

Fair enough. Tomorrow I can submit a PR for the hacky solution I put together.