From: matz@... Date: 2017-04-17T05:58:01+00:00 Subject: [ruby-core:80718] [Ruby trunk Feature#2740] Extend const_missing to pass in the nesting Issue #2740 has been updated by matz (Yukihiro Matsumoto). A long time has passed. I am a bit concerned about the situation. Do we still need this, regarding the fact I am not a big fan of autoloading? In any case, I don't like the name "NoConstantError" which should be somehow analogous to "StopIteration" but this case, we continue, not stop. Matz. ---------------------------------------- Feature #2740: Extend const_missing to pass in the nesting https://bugs.ruby-lang.org/issues/2740#change-64269 * Author: wycats (Yehuda Katz) * Status: Assigned * Priority: Normal * Assignee: matz (Yukihiro Matsumoto) * Target version: next minor ---------------------------------------- =begin At the moment, it is impossible for const_missing to differentiate between these cases: class Foo::Bar Baz end class Foo class Bar Baz end end In Rails, we implement a class loading system that loads classes from the file system if they are not found. In the above case, Foo::Baz might be stored in app/models/foo/baz.rb. We would like to be able to use the same Ruby constant lookup logic when looking up classes from the file system. class Foo::Bar Baz end Here, we should look in "app/models/foo/bar/baz.rb" and in "app/models/baz.rb" just as Ruby would search for Foo::Bar::Baz and then Object::Baz. class Foo class Bar Baz end end Here, we should look in "app/models/foo/bar/baz.rb", then "app/models/foo/baz.rb", and finally "app/models/baz.rb" just as Ruby would search for Foo::Bar::Baz, then Foo::Baz, and then Object::Baz. In order to achieve this, I propose that we extend the const_missing method to take an optional second parameter containing the nesting: class Foo class Bar def self.const_missing(id, nesting) id == :Baz nesting == [Foo::Bar] # first case nesting == [Foo::Bar, Foo] # second case end end end This would allow people who wish to do their own custom constant loading (such as Rails) to do so in a way that is consistent with Ruby's own constant lookup. In order to avoid backward-compatibility issues, we can check the arity of the const_missing method, and only pass in the nesting if a second parameter was provided. =end ---Files-------------------------------- const_missing_nesting.diff (621 Bytes) const_missing_murphy.patch (2.56 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: