From: "alexeymuranov (Alexey Muranov)" Date: 2012-07-28T22:26:43+09:00 Subject: [ruby-core:46829] [ruby-trunk - Feature #6806][Open] Support functional programming: forbid instance/class variables for ModuleName::method_name, allow for ModuleName.method_name Issue #6806 has been reported by alexeymuranov (Alexey Muranov). ---------------------------------------- Feature #6806: Support functional programming: forbid instance/class variables for ModuleName::method_name, allow for ModuleName.method_name https://bugs.ruby-lang.org/issues/6806 Author: alexeymuranov (Alexey Muranov) Status: Open Priority: Normal Assignee: Category: core Target version: =begin What would you say about this proposal? Is there a better alternative? I suggest to support functional programming in Ruby by making module methods called with (({ModuleName::method_name})) syntax raise an exception if the method uses instance or class variables (instance variables of the singleton class, of course). If i understand correctly, currently (({ModuleName::method_name})) and (({ModuleName.method_name})) behave identically, so i propose that they be different: module M module_function def f(x) x*x end def g(x) @x ||= x @x*@x end end M.f(2) # => 4 M.g(2) # => 4 M::f(3) # => 9 M::g(3) # => Error: instance variable `@x` used in a functional call `M::g` Current behavior: M.f(2) # => 4 M.g(2) # => 4 M::f(3) # => 9 M::g(3) # => 4 =end -- http://bugs.ruby-lang.org/