vim completion works with, or without, the '(' and ')'.  same with
emacs.  not sure about IDEs.

parens seems to make sense until you realize what are actually methods
in ruby


require 'rubygems' vs require('rubygems')

private 'foo' vs private('foo')

exit! vs exit!()

even?() vs even?

task :foo do ... vs task(:foo) do ...

-42.abs vs -42.abs()



learn which calls are methods, and them imagine them all with parens,
before asserting that all methods would be better without them.

the only real argument for requiring parens is so that

  o.foo  # returns the method foo

as in javascript.  other arguments are mostly religious.

cheers.