Crystal static variables

Question

Has Crystal got static variables or must I use global variables with a file / global scope ?

def test(value)
  static var = 1
  var += value
  return var
end

pp test 0 #=> 1
pp test 1 #=> 2
pp test 1 #=> 3
pp test 0 #=> 3

Answer 1

Crystal has no static variables scoped to methods. You'll need to use class variables for this:

class Test
  @@var = 1
  def self.test(value)
    @@var += value
    return @@var
  end
end

pp Test.test 0 #=> 1
pp Test.test 1 #=> 2
pp Test.test 1 #=> 3
pp Test.test 0 #=> 3

Also you can use macros class_property, class_setter or class_getter

class Test
  class_property var = 1
end

Test.var += 0
pp Test.var #=> 1
Test.var += 1
pp Test.var #=> 2
Test.var += 1
pp Test.var #=> 3
Test.var += 0
pp Test.var #=> 3