evanwalsh · March 26, 2010 17:28
diff --git a/_yerb.rb b/_yerb.rb
 # = YERB
 #
 # Who needs HAML when you have YAML + ERB? :)
 #
 # See example.yaml below for an example. You can run this code
 # by cloning this gist and then `ruby _yerb.rb example.yaml`.
 #
 # Notice that you need Ruby 1.9 so the hash order is preserved.
 # Obviously, this is just for fun. Definitely slow as hell.
 #
 require "erb"
 require "yaml"

 class YERB
  DOCTYPES = {
    :html => "<!DOCTYPE html>"
  }

  ID = /#([^\.#\(]+)/
  CLASS = /\.([^\.#\(]+)/
  ATTRIBUTES = /(\{.*\})/

  def initialize(path)
    @path = path
  end

  def result(*args)
    yaml = evaluate(File.read(@path), *args)
    to_document(YAML.load(yaml))
  end

  protected

  def evaluate(content, *args)
    ERB.new(content).result(*args)
  end

  def to_document(hash)
    doctype = hash.keys.first.to_sym

    output  = ""
    output << DOCTYPES[doctype].to_s
    output << "\n"
    output << to_tags(hash)
    output
  end

  def to_tags(hash)
    hash.map do |key, value|
      key = key.dup
      attributes = get_attributes(key)
      get_id(key, attributes)
      get_classes(key, attributes)
      tag(key, attributes, get_contents(value))
    end.join("\n")
  end

  def get_attributes(key)
    attributes = nil
    key.gsub!(ATTRIBUTES) do
      attributes = eval($1)
      nil
    end
    attributes || {}
  end

  def get_id(key, attributes)
    key.gsub!(ID) do
      attributes[:id] = $1
      nil
    end
  end

  def get_classes(key, attributes)
    classes = []
    match = key.gsub!(CLASS) do
      classes << $1
      nil
    end
    attributes[:class] = classes.join(" ") if match
  end

  def get_contents(value)
    case value
    when Hash
      to_tags(value)
    when Array
      value.map { |i| get_contents(i) }.join("\n")
    else
      value.to_s
    end
  end

  def tag(tag, attributes, content)
    attributes = attributes.map { |k,v| "#{k}=#{v.to_s.inspect}" }.join(" ")
    attributes = " #{attributes}" unless attributes.empty?
    "<#{tag}#{attributes}>#{content}</#{tag}>"
  end
 end

 puts YERB.new(ARGV.first).result if ARGV.first
diff --git a/example.yaml b/example.yaml
 html:
  head:
    title: YERB Example
  body:
    p#intro:
      Yes, this is still valid YAML after the embedded ruby code is evaluated.
    ul.cool_list:
      <% 1.upto(10) do |i| %>
      - li: <%= i %> item in the list
      <% end %>
    a{:href => "http://blog.plataformatec.com.br"}:
      "Odd, isn't it?"
	# = YERB
	#
	# Who needs HAML when you have YAML + ERB? :)
	#
	# See example.yaml below for an example. You can run this code
	# by cloning this gist and then `ruby _yerb.rb example.yaml`.
	#
	# Notice that you need Ruby 1.9 so the hash order is preserved.
	# Obviously, this is just for fun. Definitely slow as hell.
	#
	require "erb"
	require "yaml"

	class YERB
	DOCTYPES = {
	:html => "<!DOCTYPE html>"
	}

	ID = /#([^\.#\(]+)/
	CLASS = /\.([^\.#\(]+)/
	ATTRIBUTES = /(\{.*\})/

	def initialize(path)
	@path = path
	end

	def result(*args)
	yaml = evaluate(File.read(@path), *args)
	to_document(YAML.load(yaml))
	end

	protected

	def evaluate(content, *args)
	ERB.new(content).result(*args)
	end

	def to_document(hash)
	doctype = hash.keys.first.to_sym

	output = ""
	output << DOCTYPES[doctype].to_s
	output << "\n"
	output << to_tags(hash)
	output
	end

	def to_tags(hash)
	hash.map do \|key, value\|
	key = key.dup
	attributes = get_attributes(key)
	get_id(key, attributes)
	get_classes(key, attributes)
	tag(key, attributes, get_contents(value))
	end.join("\n")
	end

	def get_attributes(key)
	attributes = nil
	key.gsub!(ATTRIBUTES) do
	attributes = eval($1)
	nil
	end
	attributes \|\| {}
	end

	def get_id(key, attributes)
	key.gsub!(ID) do
	attributes[:id] = $1
	nil
	end
	end

	def get_classes(key, attributes)
	classes = []
	match = key.gsub!(CLASS) do
	classes << $1
	nil
	end
	attributes[:class] = classes.join(" ") if match
	end

	def get_contents(value)
	case value
	when Hash
	to_tags(value)
	when Array
	value.map { \|i\| get_contents(i) }.join("\n")
	else
	value.to_s
	end
	end

	def tag(tag, attributes, content)
	attributes = attributes.map { \|k,v\| "#{k}=#{v.to_s.inspect}" }.join(" ")
	attributes = " #{attributes}" unless attributes.empty?
	"<#{tag}#{attributes}>#{content}</#{tag}>"
	end
	end

	puts YERB.new(ARGV.first).result if ARGV.first
	html:
	head:
	title: YERB Example
	body:
	p#intro:
	Yes, this is still valid YAML after the embedded ruby code is evaluated.
	ul.cool_list:
	<% 1.upto(10) do \|i\| %>
	- li: <%= i %> item in the list
	<% end %>
	a{:href => "http://blog.plataformatec.com.br"}:
	"Odd, isn't it?"