Issue #21795 has been updated by matz (Yukihiro Matsumoto). I have two concerns before we move forward. On the name AST I'm not sure `ast` is the right name. The nodes returned by Prism retain concrete information such as positions, whitespace, and comments, making them closer to a Concrete Syntax Tree than an Abstract Syntax Tree. A name like `node` or `syntax_tree` might be more accurate. On the ABI version approach. Embedding a Prism ABI version in the ISeq sounds reasonable at first, but I'm worried it would make these methods reliably broken during active development on master — any time prism.c is updated ahead of a released gem, callers would get nil or an exception as a matter of course. That's a poor developer experience for people working on master. This concern points back to the suggestion from @mame: perhaps we need the built-in Prism to be exposed as a gem-independent API first, before we can ship these methods in a stable way. I'm positive about the overall direction. I just want to make sure we resolve these two points before committing to the API shape. Matz. ---------------------------------------- Feature #21795: Methods for retrieving ASTs https://bugs.ruby-lang.org/issues/21795#change-116734 * 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/