Issue #21795 has been updated by matz (Yukihiro Matsumoto). Thanks for the analysis in #13, especially the finding about node_id fragility across Prism versions. But I don't think the offset-based approach solves the real problem. It makes the identifier more robust, but the node returned is still produced by whichever Prism happens to be loaded, which may differ from the Prism that built the ISeq. Offsets only guarantee finding a node at that position, not that its meaning matches the bytecode. The real issue is one point: the parser that interpreted the running Ruby program and the parser that returns the syntax tree must be the same. Everything else is minor. There are several ways to achieve this. Exposing the built-in Prism as a gem-independent API (mame in #1), checking an ABI version (kddnewton in #4), or carrying node_id definitions in master, etc. Any of these is fine. I leave the choice to the implementers. But I'm against adding the #ast methods until this identity is guaranteed. I remain positive on the overall direction. Let's land this prerequisite first, then proceed with the methods. Matz. ---------------------------------------- Feature #21795: Methods for retrieving ASTs https://bugs.ruby-lang.org/issues/21795#change-117047 * 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/