[ruby-core:96231] [Ruby master Feature#14844] Future of RubyVM::AST?

[eregontp@gmail.com]

Issue #14844 has been updated by Eregon (Benoit Daloze).

Status changed from Closed to Open

The ticket was closed unintentionally, I reopen it.
What's the way to mention an issue in a commit but not close it?

I clarified in the documentation that RubyVM::AbstractSyntaxTree is not stable API:
https://github.com/ruby/ruby/commit/b4b22b9278007b106fe40c0191f8dcf5e7e8c0f2
```
$ ri RubyVM::AbstractSyntaxTree

AbstractSyntaxTree provides methods to parse Ruby code into abstract
syntax trees. The nodes in the tree are instances of
RubyVM::AbstractSyntaxTree::Node.

This class is MRI specific as it exposes implementation details of the
MRI abstract syntax tree.

This class is experimental and its API is not stable, therefore it might
change without notice. As examples, the order of children nodes is not
guaranteed, the number of children nodes might change, there is no way
to access children nodes by name, etc.

If you are looking for a stable API or an API working under multiple
Ruby implementations, consider using the parser gem or
Ripper. If you would like to make RubyVM::AbstractSyntaxTree stable,
please join the discussion at https://bugs.ruby-lang.org/issues/14844.
```

If people read that documentation, it should be very clear now and they can make an informed decision on whether using RubyVM::AbstractSyntaxTree as it is is appropriate for their use case.

I think we should make RubyVM::AbstractSyntaxTree a stable longer term, but for that we need to address the mentioned issues about how to evolve the API in a compatible way when the internal AST changes.
We should also probably not have it under RubyVM (#15752).

----------------------------------------
Feature #14844: Future of RubyVM::AST? 
https://bugs.ruby-lang.org/issues/14844#change-83125

* Author: rmosolgo (Robert Mosolgo)
* Status: Open
* Priority: Normal
* Assignee: yui-knk (Kaneko Yuichiro)
* Target version: 
----------------------------------------
Hi! Thanks for all your great work on the Ruby language. 

I saw the new RubyVM::AST module in 2.6.0-preview2 and I quickly went to try it out. 

I'd love to have a well-documented, user-friendly way to parse and manipulate Ruby code using the Ruby standard library, so I'm pretty excited to try it out. (I've been trying to learn Ripper recently, too: https://ripper-preview.herokuapp.com/, https://rmosolgo.github.io/ripper_events/ .)

Based on my exploration, I opened a small PR on GitHub with some documentation: https://github.com/ruby/ruby/pull/1888

I'm curious though, are there future plans for this module? For example, we might: 

- Add more details about each node (for example, we could expose the names of identifiers and operators through the node classes)
- Document each node type 

I see there is a lot more information in the C structures that we could expose, and I'm interested to help out if it's valuable. What do you think? 



-- 
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