Generating Methods in Ruby

I was trying to find a way for generating dynamic methods. My first attempt was very ugly and use a simple eval:

class DynamicMethods
  %w{ one two three }.each do |z|
    eval "def #{z}(param) puts 'Hello from \\'#{z}\\' method with \\''+param+'\\' param' end"
  end
end

Hmm… no… all this escape characters … there must be a better way. And there is. Using %Q{} …

class DynamicMethods
  %w{ one two three }.each do |z|
    eval %Q{
      def #{z}(param)
        puts "Hello form '#{z}' method with '\#{param}' param"
      end
    }
  end
end

That’s better … more readable, but i don’t have syntax highligt for this whole string. Lets try define_method …

class DynamicMethods
  %w{ one two three }.each do |z|
    define_method z do |param|
      puts "Hello from '#{z}' method with '#{param}' param"
    end
  end
end

There it is. No eval, no big strings, just a method name and code block. Beautful. All examples give you same output.

DynamicMethods.new.one("hello") # => Hello from 'one' method with 'hello' param
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