Axon Flux // A Ruby on Rails Blog

by Jasmin Blanchette of Trolltech

My favorite anecdote out of this is actually from Raymond Chen's MSDN blog about why the API call SHStripMneumonic is so heinously misspelled. Oops.

Now that the function has been published, its name is locked and can't be changed, because that would break all the programs that used the original bad spelling.

Looks like Rails 3 has just what the doctor ordered. I'm most excited about subdomain routing (we had to write some custom routes for posterous, and it's not the cleanest) and the unobtrusive JS support.

For this next one, skip to around slide 36 and this next deck has a great list of ruby dos-and-donts around Rails and Ruby style and conventions that are often not entirely obvious to people new to the platform.

This is an updated version of Henrik Nyh's text_transform! library. It allows you to extract text nodes with ease. It broke with internal changes to Hpricot 0.8.1 (some internal variables changed names), but this fixes it.

# By Henrik Nyh <http: henrik.nyh.se=""> 2007-03-28.
# Based on http://vemod.net/code/hpricot_goodies/hpricot_text_gsub.rb.
# MODIFIED BY GARRY TAN ON 4/21 to support Hpricot 0.8.1
# Licensed under the same terms as Ruby.

require "rubygems"
require "hpricot"

module Posterous
  module Extensions
    module HpricotTextTransform
      module NodeWithChildrenExtension
        def text_transform!(options={}, &block)
          return if defined?(name) and name and (name.to_sym == options[:except] or Array(options[:except]).include?(name.to_sym))
          children.each { |c| c.text_transform!(options, &block) }
        end
      end
 
      module TextNodeExtension
        def text_transform!(options={}, &block)
          content.replace yield(content)
        end
      end

      module EmptyTransform
        def text_transform!(options={}, &block)
        end
      end
    end
  end
end
Hpricot::Doc.send(:include,  Posterous::Extensions::HpricotTextTransform::NodeWithChildrenExtension)
Hpricot::Elem.send(:include, Posterous::Extensions::HpricotTextTransform::NodeWithChildrenExtension)
Hpricot::Text.send(:include, Posterous::Extensions::HpricotTextTransform::TextNodeExtension)


Hpricot::Comment.send(:include, Posterous::Extensions::HpricotTextTransform::EmptyTransform)
Hpricot::BogusETag.send(:include, Posterous::Extensions::HpricotTextTransform::EmptyTransform)
Hpricot::XMLDecl.send(:include, Posterous::Extensions::HpricotTextTransform::EmptyTransform)
Hpricot::ETag.send(:include, Posterous::Extensions::HpricotTextTransform::EmptyTransform)
Hpricot::ProcIns.send(:include, Posterous::Extensions::HpricotTextTransform::EmptyTransform)
Hpricot::DocType.send(:include, Posterous::Extensions::HpricotTextTransform::EmptyTransform)

if __FILE__ == $0
  require "test/unit"
  
  class HpricotTextTransformTest < Test::Unit::TestCase
    def assert_hpricot_transform(expected, input, options={}, &block)
      doc = Hpricot(input)
      doc.text_transform!(options, &block)
      assert_equal(expected, doc.to_s)
    end
    
    def test_with_gsub
      input    = 'xxx'
      expected = 'yyy'
      assert_hpricot_transform(expected, input, {}) { |text| text.gsub("x", "y") }
    end

    def test_with_reverse
      input    = 'hello world from <code>ruby</code>'
      expected = 'olleh morf dlrow <code>ybur</code>'
      assert_hpricot_transform(expected, input, {}) { |text| text.reverse }
    end

    def test_with_reverse_exclude_one_tag
      input    = 'hello world from <code>ruby</code>'
      expected = 'olleh morf dlrow <code>ruby</code>'
      assert_hpricot_transform(expected, input, {:except => :code}) { |text| text.reverse }
    end
    
    def test_with_reverse_exclude_multiple_tags
      input    = 'hello world from <code>ruby</code>'
      expected = 'hello morf dlrow <code>ruby</code>'
      assert_hpricot_transform(expected, input, {:except => [:a, :code]}) { |text| text.reverse }
    end
    
    def test_with_reverse_exclude_nested_tag
      input    = 'hello world from </http:><pre><code>ruby</code></pre>

'
      expected = 'olleh morf dlrow <pre><code>ruby</code></pre>

'
      assert_hpricot_transform(expected, input, {:except => :code}) { |text| text.reverse }
    end

  end
end

I've largely been unsatisfied with most Ruby books (especially the oft-referenced Pickaxe book) because they don't quite go to the depth that you need day-to-day. Often a Ruby hacker needs to resort to google-fu to understand certain particularly gnarly parts of the language.

I flipped through this and it looks like a well written, well-structured overview of the Ruby language. Thanks to Huw for a great book and for providing it online here.