From: brixen@... Date: 2014-06-03T15:48:18+00:00 Subject: [ruby-core:62921] [ruby-trunk - Bug #9898] [Open] Keyword argument oddities Issue #9898 has been reported by Brian Shirai. ---------------------------------------- Bug #9898: Keyword argument oddities https://bugs.ruby-lang.org/issues/9898 * Author: Brian Shirai * Status: Open * Priority: Normal * Assignee: * Category: * Target version: * ruby -v: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0] * Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN ---------------------------------------- Case 1: If a method takes a single argument, and the method is called with a keyword splat, the method receives the passed object, not the result of calling #to_hash on the object: # kw1.rb def m(a) a end o = Object.new def o.to_hash() puts "to_hash"; { a: 1 } end p m(**o) $ ruby -v kw1.rb ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0] to_hash # Would someone please explain why the result of #to_hash in not passed to the method? Case 2: If the method takes a keyword argument, #to_hash is called at the send site and at the receiver: # kw2.rb def mk(a:) a end o = Object.new def o.to_hash() puts "to_hash"; { a: 1 } end p mk(**o) $ ruby -v kw2.rb ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0] to_hash to_hash 1 Would someone please explain why #to_hash is called at both the send site and at the receiver? -- https://bugs.ruby-lang.org/