buildable.rb

Path: lib/more/facets/buildable.rb
Last Update: Tue Dec 02 09:46:42 -0500 2008

Buildable / BuildingBlock

Build content programatically with Ruby and Ruby‘s blocks. 

  require 'facets'
  require 'xmlhelper'

  builder = BuildingBlock.new(XMLHelper, :element)

  doc = builder.html do

    head do
      title "Test"
    end

    body do
      i "Hello"
      br
      text "Test"
      text "Hey"
    end

  end

produces 

  <html><head><title>Test</title><body><i>Hello</i><br />TestHey</body></html>

All calls within the block are routed via the Helper Module‘s constructor method (element in the above example) unless they are defined by the helper module, in which case they are sent to the helper module directly. The results of these invocations are appended to the output buffer. To prevent this, prefix the method with ‘call_’.

Sometimes keywords can get in the way of a construction. In these cases you can ensure use of constructor method by calling the special build! command. You can also add verbatium text to the output via the #<< operator. Some common Ruby‘s built-in methods treated as keywords: 

     inspect
     instance_eval
     respond_to?
     singleton_method_undefined
     initialize
     method_missing
     to_str
     to_s

And a few other speciality methods besides: 

     to_buffer
     build!
     <<

This work was of course inspired by many great minds, and represents a concise and simple means of accomplishing this pattern of design, which is unique to Ruby.

Buildable is mixin variation of BuildingBlock. 

  require 'facets/buildable'
  require 'xmlmarkup'  # hypothetical library

  module XMLMarkup
    include Buildable
    alias :build :element
  end

  doc = XMLMarkup.build do
    html do
      head do
        title "Test"
      end
      body do
        i "Hello"
        br
        text "Test"
        text "Hey"
      end
    end
  end

produces 

  <html><head><title>Test</title><body><i>Hello</i><br />TestHey</body></html>

This is based on BuildingBlock. Refer to it for more information.

Authors

  • Thomas Sawyer

Todo

Copying

Copyright (c) 2006 Thomas Sawyer

Ruby License

This module is free software. You may use, modify, and/or redistribute this software under the same terms as Ruby.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

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