Issue #21795 has been updated by matz (Yukihiro Matsumoto). Status changed from Closed to Open I approve introducing `#syntax_tree`, and I like the name. Please land it as an experimental feature as you propose in [#note-27](https://bugs.ruby-lang.org/issues/21795#note-27). On the prism version mismatch, I choose your approach: warn and keep working. A method that stops working after `bundle update` is worse for users than one that works in almost all cases and says so. This does relax the condition I stated in [#note-19](https://bugs.ruby-lang.org/issues/21795#note-19); exact parser identity now holds only with the default gem, and I accept that for an experimental feature. Two things in exchange. Please keep the warning verbose-only, so that it does not become noise for people who cannot act on it. And please state plainly in the documentation that with a different prism version the returned node may not correspond to the code that was actually executed -- not merely that the result is "not guaranteed". For the return value under `--parser=parse.y`, and the other details raised by @kddnewton and @Eregon, please continue the discussion and settle them among yourselves. I do not need to decide those. This ticket seems to have been closed by the source hash commit. The feature itself is not done yet, so I reopened. Matz. ---------------------------------------- Feature #21795: Methods for retrieving ASTs https://bugs.ruby-lang.org/issues/21795#change-118411 * Author: kddnewton (Kevin Newton) * Status: Open ---------------------------------------- I would like to propose a handful of methods for retrieving ASTs from various objects that correspond to locations in code. This includes: * Proc#ast * Method#ast * UnboundMethod#ast * Thread::Backtrace::Location#ast * TracePoint#ast (on call/return events) The purpose of this is to make tooling easier to write and maintain. Specifically, this would be able to be used in irb, power_assert, error_highlight, and various other tools both in core and not that make use of source code. There have been many previous discussions of retrieving node_id, source_location, source, etc. All of these use cases are covered by returning the AST for some entity. In this case node_id becomes an implementation detail, invisible to the user. Source location can be derived from the information on the AST itself. Similarly, source can be derived from the AST. Internally, I do not think we have to store any more information than we already do (since we have node_id for the first four of these, it becomes rather trivial). For TracePoint we can have a larger discussion about it, but I think it should not be too much work. In terms of implementation, the only caveat I would put is that if the ISEQ were compiled through the old parser/compiler, this should return `nil`, as the node ids do not match up and we do not want to further propagate the RubyVM::AST API. The reason I am opening up this ticket with 5 different methods requested in it is to get approval first for the direction, then I can open individual tickets or just PRs for each method. I believe this feature would ease the maintenance burden of many core libraries, and unify otherwise disparate efforts to achieve the same thing. -- https://bugs.ruby-lang.org/