ruby module as collection of methods
I have a rails app that loads lots of data from some java services. I'm writing a module that will allow me to populate some select boxes with this data and I'm trying to include these properly so I can reference them in my views. Here's my module
module FilterOptions
module Select
def some_select
return "some information"
end
end
end
My idea was to include FilterOptions in my application_helper, and I thought I could then reference my methods using Select::some_select
This is not the case. I have to include FilterOptions::Select
then I can reference the method some_select
on its own. I don't want that though as I think it's a bit confusing to someone that may not know that some_select
is coming from my own m开发者_运维百科odule.
So, how do I write methods of a module that are like public static methods so I can include my main module, and reference my methods using the sub-module namespace like Select::some_select
If you define module methods within the context of the module itself, they can be called without import:
module FilterOptions
module Select
def self.some_select
return "some information"
end
end
end
puts FilterOptions::Select.some_select
# => "some information"
It is also possible to import one module, and not import the next, refer to it by name instead:
include FilterOptions
puts Select.some_select
# => "some information"
module_function causes a module function to be callable either as an instance method or as a module function:
#!/usr/bin/ruby1.8
module Foo
def foo
puts "foo"
end
module_function :foo
end
Foo.foo # => foo
Foo::foo # => foo
include Foo
foo # => foo
Sometimes you want every method in a module to be a "module function," but it can get tedious and repetitive to keep saying "module_function" over and over. In that case, just have your module extend itself:
!/usr/bin/ruby1.8
module Foo
extend self
def foo
puts "foo"
end
end
Foo.foo # => foo
Foo::foo # => foo
include Foo
foo # => foo
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