Unable to refine class with CONSTANT
When refining a class (such as
String in the following example) it is impossible to assign a constant. The constant will get attached to the module containing the refinement instead of the refined class. When inside of a
refine block constants should get assigned to that class.
module Foobar refine String do FOO = "BAR" def foobar "foobar" end end end using Foobar puts "".class::FOO # => uninitialized constant String::FOO (NameError) puts "".foobar # => "foobar"
Updated by engineersmnky (Mike Hein) over 6 years ago
I would like to also mention that this impacts class_variables as well
module Foobar @@baz = "boom" refine String do @@foo = "bar" def foobar @@foo end def bazical @@baz end end end using Foobar Foobar.class_variables #=> [:@@baz, :@@foo] "".bazical #=> "boom" "".foobar #=> "bar"
The first one I understand since the block can utilize variables and methods outside of itself. The second one really confuses me as I didn't expect it to skip over String and end up in Foobar. It also does not raise any warning about
warning: class variable access from toplevel. Just as I would have expected constants to raise a
SyntaxError for dynamic assignment. Instance variables seem to be ignored all together from what I can see.
Updated by matz (Yukihiro Matsumoto) over 6 years ago
- Status changed from Open to Feedback
Constants (and class variables) are not included in refinement modification. Constants still belong to outer class.
If we change this, we have to make incompatible change to constant scoping rules.
I don't think its wise.
But maybe above class variables case should be warned, probably.