Modules & include

[Andreas Schwarz]

Why do I get an exception? Shouldn't Mod2 have the method return_true
because it included Mod1?

irb(main):001:0> module Mod1
irb(main):002:1> def return_true
irb(main):003:2> true
irb(main):004:2> end
irb(main):005:1> end
=> nil
irb(main):006:0> module Mod2
irb(main):007:1> include Mod1
irb(main):008:1> def self.test
irb(main):009:2> return_true
irb(main):010:2> end
irb(main):011:1> end
=> nil
irb(main):012:0> Mod2.test
NameError: undefined local variable or method `return_true' for Mod2:Module

 

[Mark Hubbart]

Why do I get an exception? Shouldn't Mod2 have the method return_true
because it included Mod1?

irb(main):001:0> module Mod1
irb(main):002:1> def return_true
irb(main):003:2> true
irb(main):004:2> end
irb(main):005:1> end
=> nil
irb(main):006:0> module Mod2
irb(main):007:1> include Mod1
irb(main):008:1> def self.test
irb(main):009:2> return_true
irb(main):010:2> end
irb(main):011:1> end
=> nil
irb(main):012:0> Mod2.test
NameError: undefined local variable or method `return_true' for
Mod2:Module

Mod2 itself does not have that method; if you had defined return_true
as 'self.return_true' then it would have worked. Or you could have
called 'module_method :return_true', I think. Otherwise, those methods
get added as instance methods. You can mix them into a class:
NoMethodError: private method `test' called for Mod2:Module
from (irb):111=> true

cheers,
--Mark

 

[Mauricio Fernández]

Why do I get an exception? Shouldn't Mod2 have the method return_true
because it included Mod1?

irb(main):001:0> module Mod1
irb(main):002:1> def return_true
irb(main):003:2> true
irb(main):004:2> end
irb(main):005:1> end
=> nil
irb(main):006:0> module Mod2
irb(main):007:1> include Mod1 =======
extend
irb(main):008:1> def self.test

=========
if this were def test, include Mod1 would do what you want (or the
other way around, you'd want what include Mod1 does

irb(main):009:2> return_true
irb(main):010:2> end
irb(main):011:1> end
=> nil
irb(main):012:0> Mod2.test
NameError: undefined local variable or method `return_true' for Mod2:Module

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