Error recovery/resilience

Currently, all of the parse functions return Result<ast, ParseError>. This means that if the file has a syntax error, we get the error and nothing else. However, there are some use cases in which having access to parts which did parse successfully would be beneficial:

• Language servers usually want to keep functioning when the file is temporarily broken during editing.
• Linters might want to skip over broken parts and continue reporting lints, or maybe up to the syntax error.

On the other hand, interpreters usually don't have too much use for this AFAIK.

lalrpop seems to have some support for error recovery: https://lalrpop.github.io/lalrpop/tutorial/008_error_recovery.html
Alex Kladov has written about error recovery, most recently here: https://matklad.github.io/2023/05/21/resilient-ll-parsing-tutorial.html

Is RustPython/Parser interested in error recovery or is it out of scope?

先閱讀 parser 的 parse 函式，以及它們目前如何回傳 Result<ast, ParseError>。檢視連結的 LALRPOP 與 resilient-LL parsing 資料，以比較錯誤復原方式。完成的標準是：專案已就錯誤復原是否屬於範圍達成共識；若屬於範圍，則已有保留成功解析部分的具體設計。