Feature #17380
closedUseful `include/prepend` in `refine`
Description
Currently, prepend/include
within a refine
block leads to a method not being to see itself, or others defined in the same module:
module Code
def recurse(value = nil)
return value if value
recurse(42) # => NoMethodError!!!
end
end
module Extension
refine Object do
include Code
end
end
using Extension
:x.recurse(:y) # => :y (ok)
:x.recurse # => NoMethodError, was hoping for 42
I find this unintuitive and not useful.
The conclusion of the current situation from @shugo (Shugo Maeda) and others is "I don't recommend module inclusion to define refined methods"
Could we change this situation so it can be recommended to use it?
What I believe would be more useful and is what I expected was that include/prepend
within a Module
would bring in the current methods in the Module, with the current refinements activated.
One use-case in particular is to publish libraries where one can give the option to the user to either:
- call
using GreatExtension
in each and every file that need it - or
MyClass.prepend GreatExtension
once.
While Jeremy Evans found a way to do it, it remains challenging and unnatural.
Updated by Eregon (Benoit Daloze) almost 4 years ago
- Related to Bug #17374: Refined methods aren't visible from a refinement's module added
Updated by Eregon (Benoit Daloze) almost 4 years ago
Maybe we should allow include RefinedImplementation
from https://bugs.ruby-lang.org/issues/17374#note-8 ?
Copying methods manually seems to have a very similar effect, but it would be more convenient.
Updated by Dan0042 (Daniel DeLorme) almost 4 years ago
It would be nice if prepend
/include
worked within a refine
block, but if they don't then at least it should raise an error. In that respect I disagree with closing #17374; even if the result is "expected", the fact that including a module is effectively a no-op should be considered a bug. Silently failing to have an effect is not so good.
Updated by marcandre (Marc-Andre Lafortune) almost 4 years ago
Dan0042 (Daniel DeLorme) wrote in #note-3:
including a module is effectively a no-op
It isn't a no-op, as it does bring each method in the refinement, but those methods "live" outside of said refinement. See my example above where :x.recurse(:y) # => :y (ok)
.
Updated by Dan0042 (Daniel DeLorme) almost 4 years ago
marcandre (Marc-Andre Lafortune) wrote in #note-4:
It isn't a no-op, as it does bring each method in the refinement, but those methods "live" outside of said refinement. See my example above where
:x.recurse(:y) # => :y (ok)
.
Yes, I understand that, but even if the methods are technically in the refinement, if they are unreachable then effectively it's the same as a no-op. Although as the example shows it's more like a "half-op"; the methods are reachable from the outside but not the inside.
Updated by jeremyevans0 (Jeremy Evans) about 3 years ago
- Status changed from Open to Closed