Tutorial :Rewrite simple ruby function to use a block



Question:

I do not know the correct terminology. I tried to google it and could not find anything for that reason.

I am writing a Ruby library, and I want to rewrite the functions so they work as below as I prefer it for readability (inside a block?)

I have a function that does this

@dwg = Dwg.new("test.dwg")  @dwg.line([0,0,0],[1,1,0])  @dwg.save  

I want to rewrite it so it works like this

Dwg.new("test.dwg") do       line([0,0,0],[1,1,0])     save    end  

Can you outline the way I go about this?


Solution:1

You can define Dwg's initializer to take a block, and then yield to that block with instance_eval, like so:

class MyClass    def initialize(name, &block)      @name = name      instance_eval &block    end      def show_name      puts 'My name is ' + @name    end  end    MyClass.new('mud') do    show_name  end    # >> My name is mud  

For more information, see the "Blocks for Interface Simplification" section in the recently Creative-Commons-licensed Chapter 2 of Gregory Brown's excellent Ruby Best Practices book. (Its author and publisher are gradually CCing the entire thing, but you can of course still buy a copy to support the work. The iPhone edition is particularly affordable.)


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