Rascal formatter based on Box and layoutDiff, including upgrades of Tree2Box, Box2Text and layoutDiff

[jurgenvinju]

Rascal is a pretty big language so this pushes the new toBox and format and layoutDiff functions to the max.

• The goal is to formulate toBox rules such that the formatter produces beautiful layout, and
• We identify bugs and efficiency issues in toBox, format and layoutDiff and fix them immediately.
• We add box operators with variable argument lists to eliminate a level of superfluous brackets
• We test for exceptions, parse errors and comment preservation, on all files of the standard library and the larger files in the Compiler and checker.
• re-implementation (optimized) of U and G
• integration tests succeed https://github.com/usethesource/rascal-core-big-tests/actions/runs/23592431666

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46%. Comparing base (30cf1b2) to head (a3bf748).

Additional details and impacted files

@@           Coverage Diff           @@
##              main   #2346   +/-   ##
=======================================
  Coverage       46%     46%           
+ Complexity    6721    6718    -3     
=======================================
  Files          794     794           
  Lines        65905   65900    -5     
  Branches      9884    9879    -5     
=======================================
- Hits         30827   30825    -2     
+ Misses       32690   32685    -5     
- Partials      2388    2390    +2     

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[toinehartman]

In the spirit of eat your own dog food, I gave it a spin

rascal>formatRascalFile(|file:///c:/Users/toine/swat/projects/Rascal/rascal/src/org/rascalmpl/library/lang/rascal/format/Rascal.rsc|);
|TODO:///|: ParseError(|file:///c:/Users/toine/swat/projects/Rascal/rascal/src/org/rascalmpl/library/lang/rascal/format/Rascal.rsc|(2734,1,<67,73>,<67,74>))

The error is not in the original file:

rascal>parse(#start[Module], |file:///c:/Users/toine/swat/projects/Rascal/rascal/src/org/rascalmpl/library/lang/rascal/format/Rascal.rsc|);
start[Module]: (start[Module]) `@license{
Copyright (c) 2022, NWO-I Centrum Wiskunde & Informatica (CWI)
All rights reserved.
...

I did not investigate further, but it might very well be introduced by our toBox rules.

[toinehartman]

Nice! Really cool to test declarative formatting on a mature languge.

I think finding a formatting for Rascal that's commonly agreed on might be controversial...

[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

[jurgenvinju]

• the big work is done; the formatting architecture works well for Rascal
• there is room for optimization in Box2Text. The other components seem flashy.
• the formatter for Rascal itself will probably receive more love in the coming months. there are always more exceptions to add. but in general it looks good in the entire standard library and the checker and the compiler.
• we have not applied the checker to the actual Rascal source files and committed the result, because that would generate too much noise.

[jurgenvinju]

Converting to draft until the compilation and the tests run again.

[sonarqubecloud]

Quality Gate failed

Failed conditions
23.6% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud