> I guess it's hard for me to edit things that I don't see right in front of me or aren't super simple changes (like name changes). Or at least, basic things I can reason about (such as finding by regex then deleting by textobject or something).
This is actually what's nice about tools like ast-grep. The pattern language reads almost like the code itself so you can see the transformation right in front of you (at least for small-scale cases) and reason about it. TypeScript examples:
# convert guard clauses to optional chaining
ast-grep -pattern '$A && $A.$B' --rewrite '$A?.$B' -lang ts
# convert self-assignment to nullish coalescing assignment
ast-grep -pattern '$X = $X ?? $Y' --rewrite '$X ??= $Y' -l ts
# convert arrow functions to function declarations (need separate patterns for async & for return-type-annotated though)
ast-grep -pattern 'const $NAME = ($$$PARAMS) => { $$$BODY }' --rewrite 'function $NAME($$$PARAMS) { $$$BODY }' -l ts
# convert indexOf checks to .includes()
ast-grep -pattern '$A.indexOf($B) !== -1' --rewrite '$A.includes($B)' -l ts
Sadly coding agents are still pretty bad at writing ast-grep patterns probably due to sparse training data. Hopefully that improves. The tool itself is solid!
While at it, https://github.com/semgrep/semgrep was around for several years, too.
Came here to recommend ast-grep too!
If your editor of choice supports an extension (vscode does for example) it's a very easy on-ramp for a better search/replace than regex offers. It's syntax-aware so you don't need care about whitespace, indentation etc. Very easy to dip your toes in where a regex would get complex fast, or require multiple passes.
I converted a codebase from commonjs to esm trivially with a few commands right after first installing it. Super useful.
I hope LLMs eventually start operating at this level rather than raw text. And likewise for them to leverage the language server to take advantage of built in refactorings etc
I don't know which editors support this but there's also, for lack of a better word, context aware grep. For example, search and replace foo with bar but only inside strings, or only inside comments, or only variables, or only methods, not class names (maybe ast-grep does this).