✨ Add parser support for backslash continuation

[TheAfroOfDoom]

Summary

closes #1069

this PR adds backslash continuation for command and argument parsers in mcfunctions.

Preview

command parser	argument parser (+ node range highlighting correctly)
command and argument parser together	correct index mappings across lines
command and argument completers not working yet	...but completers do work as long as you're not splitting the node (?) up between lines?

Next steps

(these should be ticketized)

• fix colorizer not really working across lines (e.g. open/close brackets [/] across lines)
  • plenty of examples of this in the above images
• fix command completer mostly not working

[SPGoding]

amazing work! i'll look over this when i get more time.

open/close brackets [/] across lines

i believe that is not an us issue. we don't colorize brackets. do you have some other extensions?

[SPGoding]

the completion is computed correctly but VS Code doesn't display them.

Old information from when I was trouble shooting

i think this happens because VS Code uses text in the `replace` range to filter through the options, which does not match any of the `label` of the completion items. e.g., the `replace` range is `[(8, 0); (9, 3))`, so the source text VS Code uses to filter options is `ad\huh`. the `label` of the completion item is `advancement`, which does not match the source text, so no completion item is shown. one way i can think of to fix this is to add `filterText` like `ad\vancement` to the completion items so VS Code can filter the options properly (and if we can construct those `filterText` might as well set the `newText` to them so the user gets to keep their insane word-breaking line continuity). another way i can think of to fix it is to just set the `filterText` to an empty string so no filtering is done by the client, and we could do filtering on server side given that we have more information.

nvm, tried to hard code some filterText values and none of these work. i even tried to make filterText exactly the text in the replace range and it still doesn't work

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in microsoft/vscode there's this comment explaining how filtering works. my understanding was mostly correct, except that VS Code does not support ranges that span multiple lines as the "prefix". a hacky workaround i can think of would be to make the replace range in textEdit stop at the end of the first line, then use additionalTextEdits to delete the following lines.

[SPGoding]

Would it make sense to wrap concatOnTrailingBackslash on the entire command parser, instead of on individual argument parsers? With the current implementation the built-in parsers in mcfunction package (trailing content and unknown parser) does not support backslash continuation.

For something like this,

advancement ! \
aartsarst

The ! is unparsable, so anything after it is considered to be trailing content. The expected trailing content should expand into the second line, but with the current implementation the second line is treated as the start of a new command.

[TheAfroOfDoom]

Would it make sense to wrap concatOnTrailingBackslash on the entire command parser

i believe it already was wrapped around the command parser:

https://github.com/TheAfroOfDoom/Spyglass/blob/059a825c4ea4e799b9ed2ebb17929e492d9a2b33/packages/mcfunction/src/parser/command.ts#L96-L103

however...

The ! is unparsable, so anything after it is considered to be trailing content. The expected trailing content should expand into the second line, but with the current implementation the second line is treated as the start of a new command.

good catch. when looking into where exactly we should place the concat parser i was reminded of our comment and command_macro parsing that is done in the mcfunction entry parser

this made me wonder how Minecraft would parse something like this:

# a comment \
say i will not say

turns out it prints nothing, meaning the backslash continuation is the first thing that happens when Minecraft parses a .mcfunction file (even prior to comment parsing). this isn't too crazy but was interesting to me nonetheless

the fix for this is fairly simple and actually lets me simplify some code/remove unnecessary test code. commits soonTM

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preview

[TheAfroOfDoom]

still need to fix build

fixed in 67eab68 (#1180)

[TheAfroOfDoom]

apparently i have no idea how to cleanly do a merge commit RIP