Incorrect highlighting of multiline import statements

[bgriffith]

Currently multi-line import statements aren't highlighted correctly;

import foo from 'bar';

import foo
from 'bar'

import foo
  from 'bar'

This is on the master branch.

[Alhadis]

The current pattern is using (?=;|$) to terminate the import match. Since these statements are obviously allowed to span lines, it seems like the $ should be dropped. The formal import syntax also mandates a terminating semicolon be used (in both the stable and draft versions of the modules spec):

• Imports: 2015
• Imports: 2017

So the reason I'm hesitant to remove the $ from the end match is because Babel accepts semicolon-less import statements. And since there's no native support for modules yet, it's tough to trust anything but a transpiler's output... 😟

/cc @50Wliu for feedback

[winstliu]

I would trust the spec more than I would trust a transpiler.

[Alhadis]

Likewise. But would you reckon removing the end-of-line match will hit much existing code?

@bgriffith, any input? I'm really not well-versed in the area of transpilers..

(To be honest, I'm happy just sticking with CommonJS modules until the spec is supported natively. No rush. :D)

[Alhadis]

One week later, no response. Fixing this now so I don't forget it later (which I will).

@50Wliu FWIW, it's likely the spec would mandate the semicolon usage, because import/export statements are parsed statically (as opposed to evaluated). It makes sense from a tokeniser's standpoint to stop at a single character, instead of maintain a table of symbols in memory while lexing.

[maxbrunsfeld]

The formal import syntax also mandates a terminating semicolon be used.

The reason I'm hesitant to remove the $ from the end match is because Babel accepts semicolon-less import statements.

I would trust the spec more than I would trust a transpiler.

What the spec says doesn't matter, because the spec requires a semicolon after any statement (e.g. a return statement). Of course, we don't want syntax highlighting to completely break if the user omits a semicolon after a return statement. The same is true for import statements.

EDIT

Unfortunately AFAICT, this means we cannot fix the problem this issue describes. The text-mate grammar system simply isn't powerful enough 😞 .

[winstliu]

This isn't fixable until we get context-awareness or multiline matching.