Adds an algorithm to compute where to insert brackets to repair
bracketing mismatches during lexing. This takes indentation, as well as
a number of other cues, into account to predict where the brackets
should have gone. Detects when there is ambiguity between solutions and
makes no suggestion in that case. Reduces the problem by splitting on
properly bracketed top-level constructs, then uses a beam search to find
good candidate solutions quickly.
This includes both a fuzzer and an eval tool that can be used to
determine how well the algorithm fares against a given corpus of valid
Carbon code, by damaging it in various ways and seeing whether the
algorithm can correctly fix it. On all the eval modes, this algorithm
can correctly infer the positions for over 80% of lost brackets (and can
correctly restore 95+% of brackets in some modes), with low rates of
incorrect suggestions.
See added documentation for full details.
Assisted-by: Gemini via Antigravity, Claude via Claude Code
We've talked about adding the title to the filename several times over
the years and it seems really valuable. This requires us to compute a
"slug" for the title spelling that can be part of the filename.
Beyond that, we crossed 7000 recently, and so it seems likely that we
will need to add digits sooner rather than later here, so this goes
ahead and moves us to 6 digits so we don't have to adjust again for a
reasonable length of time.
To implement this and ensure we can sustain it going forward this adds a
tool to our pre-commit that validates (and corrects if needed) the
filename.
In order to update everything and keep links working, there are a _lot_
of changes, but the most interesting for direct review are in
`proposals/scripts`.
Assisted-by: Antigravity with Gemini
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
As part of using the evolution process with the toolchain, alternatives
should
be in proposals. This proposal migrates existing alternatives here.
Assisted-by: Google Antigravity with Gemini 3 Flash
Richard Smith
Chandler CarruthandRichard Smith
Jon Ross-Perkins
