Feature #21365: Add `Namespace#eval`

• Status: Open
• Assignee: -
• Target version: -

[tenderlovemaking (Aaron Patterson)]

I would like a way to eval code on to a Namespace object. Could we add an eval method that doesn't take a binding object? Writing a new file every time I want to test Namespaces is too cumbersome.

Thanks!

[matheusrich (Matheus Richard)]

I'm curious why eval and not instance_eval?

[Eregon (Benoit Daloze)]

Yep, agreed it'd be far more convenient for testing Namespace.

matheusrich (Matheus Richard) wrote in #note-1:

I'm curious why eval and not instance_eval?

Why instance_eval? The distinction between eval/class_eval/instance_eval does not seem relevant here.

Though of course the semantics should be the same as writing the code to a file + Namespace#require so e.g. ns.eval "def foo = 42" defines method foo on ns' copy of Object methods.

[matheusrich (Matheus Richard)]

@Eregon (Benoit Daloze) I feel like that's more consistent with the rest of the language. I can't remember if any object as a eval method. But evaluating some code in a particular instance context makes me think of instance_eval.

[ufuk (Ufuk Kayserilioglu)]

matheusrich (Matheus Richard) wrote in #note-3:

@Eregon (Benoit Daloze) I feel like that's more consistent with the rest of the language. I can't remember if any object as a eval method. But evaluating some code in a particular instance context makes me think of instance_eval.

I am not sure I understand. All objects have an eval method in the form of Kernel#eval: https://ruby-doc.org/3.4.1/Kernel.html#method-i-eval

[matheusrich (Matheus Richard)]

@ufuk (Ufuk Kayserilioglu) fair point. Although it is a private method, so we're never doing "foo".eval(bar).