Support functional programming: forbid instance/class variables for ModuleName::method_name, allow for ModuleName.method_name
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 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`
M.f(2) # => 4 M.g(2) # => 4 M::f(3) # => 9 M::g(3) # => 4