From: mame@...
Date: 2021-04-17T07:38:07+00:00
Subject: [ruby-core:103494] [Ruby master Feature#17749] Const source	location without name

Issue #17749 has been updated by mame (Yusuke Endoh).


Thank you! Then, I think the patch should use const_source_location info instead of adding `file` and `line` fields.

tenderlovemaking (Aaron Patterson) wrote in #note-9:
> For my use case the difference doesn't matter.  If we had `namespace` as in #17753, then I think I could write `klass.namespace.const_source_location(klass.name)` (or make the implementation do this).

Sorry I am missing somthing but if an anonymous class does not matter at all, I think you are already able to write `Object.const_source_location(klass.name)` even if #17753 is not accepted.

----------------------------------------
Feature #17749: Const source location without name
https://bugs.ruby-lang.org/issues/17749#change-91590

* Author: tenderlovemaking (Aaron Patterson)
* Status: Open
* Priority: Normal
----------------------------------------
Hi,

I would like to be able to ask a class or module what its source location is without knowing the name.  For example, I want to do this:

```ruby
module A
  class B
  end
end

p A::B.const_source_location
```

In other works `A::B.const_source_location` would be equivalent to `A.const_source_location(:B)`.

The reason I want to do this is because sometimes it is very difficult to get the name of a constant, and sometimes I don't have access to the constant that "encloses" the class or module.

One example:

```ruby
ObjectSpace.each_object(Class) do |k|
  p k.const_source_location
end
```

In this case I have class objects, but I can't tell what constant `k` was defined *inside* of.  Also I can't trust the "name" method on `k` because sometimes it's not the default method (of course I could work around that, but it's not fun).

I've attached a patch that implements the feature, and there is a PR [here](https://github.com/ruby/ruby/pull/4324)

Side note: I think I would like "source_location" better than `const_source_location`, but I wanted to just file a feature request so we could talk about the feature in general.

---Files--------------------------------
0001-Add-constant-location-information-to-classes.patch (5.34 KB)
0001-Add-constant-location-information-to-classes.patch (5.97 KB)


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