Parametric: formatting

[toinehartman]

• Implementing the formatting and rangeFormatting LSP APIs. Both use the same contribution, where for (whole-file) formatting _range == _input@\loc.

Design:

data LanguageService = formatting(list[TextEdit](Focus _focus, FormattingOptions _opts) formattingService);

data FormattingOptions(
        int tabSize = 4
      , bool insertSpaces = true
      , bool trimTrailingWhitespace = false
      , bool insertFinalNewline = false
      , bool trimFinalNewlines = false
) = formattingOptions();

Closes #130.

• added formatting support for Rascal as well, since that shares the essential new focus computation based on a selection range with the current PR.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[DavyLandman]

I see this is a bit of a challenging API, especially if we want to make this more user-friendly for DSL users.

I have the feeling we should involve @jurgenvinju who has been on the topic of formatting/pretty-printing for quite some time already. I suspect that we're missing some opportunities of matching this up with something already in the standard library, or something that we might should add to the standard library first.

[DavyLandman]

This PR is missing the adjacent: rangeFormatting functionality.

[DavyLandman]

I think this is going in the right direction, but I'm not sure what I should have been reviewing, the implementation or the design?

[jurgenvinju]

Is there an opportunity to use the Focus abstraction for this contribution? Especially for the range alternative.

That way language engineers don't have to go search for the right trees anymore, and they could easily support only a few top-level types for starters, and they could easily recover the required indentation level from the parent tree's layout siblings.

[toinehartman]

Is there an opportunity to use the Focus abstraction for this contribution? Especially for the range alternative.

@jurgenvinju I thought about this, but the tricky part there is that a range does not necessarily correspond to an exact tree. Even if we give a focus tree that ends at the largest tree encapsulating the range, there would still be the need to filter the edits so they are not outside of the given range.

[sonarqubecloud]

Quality Gate passed

Issues
10 New issues
0 Accepted issues

Measures
0 Security Hotspots
42.3% Coverage on New Code
0.2% Duplication on New Code

See analysis details on SonarQube Cloud

[github-advanced-security]

ESLint found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.

[sonarqubecloud]

Quality Gate passed

Issues
12 New issues
0 Accepted issues

Measures
0 Security Hotspots
39.2% Coverage on New Code
0.2% Duplication on New Code

See analysis details on SonarQube Cloud

[toinehartman]

@jurgenvinju and I made sure that all the changes necessary to format Rascal code are now available in #1102. This PR will be left draft for a while until we are ready to clean this up and resume work on DSL formatting.