How to redefine a Ruby constant without warning?

Question

I\'m running some Ruby code which evals a Ruby file every time its date changes. In the file, I have constant definitions, like

Tau = 2 * Pi

<

Answer 1

The following module may do what you want. If not it may provide some pointers to your solution

module RemovableConstants

  def def_if_not_defined(const, value)
    self.class.const_set(const, value) unless self.class.const_defined?(const)
  end

  def redef_without_warning(const, value)
    self.class.send(:remove_const, const) if self.class.const_defined?(const)
    self.class.const_set(const, value)
  end
end

And as an example of using it

class A
  include RemovableConstants

  def initialize
    def_if_not_defined("Foo", "ABC")
    def_if_not_defined("Bar", "DEF")
  end

  def show_constants
    puts "Foo is #{Foo}"
    puts "Bar is #{Bar}"
  end

  def reload
    redef_without_warning("Foo", "GHI")
    redef_without_warning("Bar", "JKL")
  end

end

a = A.new
a.show_constants
a.reload
a.show_constants

Gives the following output

Foo is ABC
Bar is DEF
Foo is GHI
Bar is JKL

Forgive me if i've broken any ruby taboos here as I am still getting my head around some of the Module:Class:Eigenclass structure within Ruby