[ruby-core:119317] [Ruby master Bug#20761] [DOC] `RubyVM::AbstractSyntaxTree.of` examples raise because parser is prism by default

["Earlopain (A S) via ruby-core" <ruby-core@ml.ruby-lang.org>]

Issue #20761 has been updated by Earlopain (A S).


Eregon (Benoit Daloze) wrote in #note-7:
> @Earlopain Is there a reason you need this and cannot just use e.g. `Prism.parse("proc {1 + 2}")`?
> 
> A cleaner and portable way to achieve this functionality from a Proc/Method would be if there is a way to retrieve their precise source location, i.e. start & end byte offsets or equivalent (`#source_location` currently only gives the start line and column).

This question specifically was about usage that Rails recently adopted for printing the source code of a proc when doing `assert_no_difference(-> { foo })` inside the assertion error message. https://github.com/rails/rails/pull/52036. kddnewton has since raised a PR switching it over to `RubyVM::InstructionSequence` which of course has the same interoperability problems. https://github.com/rails/rails/pull/53055

If `source_location` would provide richer information, then it would be an easy switch. The PR basically already doing that through `:code_location` from the iseq. I remember an issue about it, maybe this https://bugs.ruby-lang.org/issues/8751, though I thought it was a bit more recently discussed.

----------------------------------------
Bug #20761: [DOC] `RubyVM::AbstractSyntaxTree.of` examples raise because parser is prism by default
https://bugs.ruby-lang.org/issues/20761#change-109927

* Author: Earlopain (A S)
* Status: Closed
* ruby -v: 3.4-dev
* Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
https://docs.ruby-lang.org/en/master/RubyVM/AbstractSyntaxTree.html#method-c-of

```rb
RubyVM::AbstractSyntaxTree.of(proc {1 + 2})
# => <internal:ast>:97:in 'RubyVM::AbstractSyntaxTree.of': cannot get AST for ISEQ compiled by prism (RuntimeError)
```

Same for the method example. Is this method even functional when prism is used, or is the prism gem able to do this somehow?



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