Class: Markaby::Builder

Inherits:
Object show all
Defined in:
lib/gems/markaby-0.5/lib/markaby/builder.rb,
lib/gems/markaby-0.5/lib/markaby/rails.rb

Overview

The Markaby::Builder class is the central gear in the system. When using from Ruby code, this is the only class you need to instantiate directly.

mab = Markaby::Builder.new
mab.html do
  head { title "Boats.com" }
  body do
    h1 "Boats.com has great deals"
    ul do
      li "$49 for a canoe"
      li "$39 for a raft"
      li "$29 for a huge boot that floats and can fit 5 people"
    end
  end
end
puts mab.to_s

Constant Summary collapse

@@default = 
{
  :indent => 0,
  :output_helpers => true,
  :output_xml_instruction => true,
  :output_meta_tag => true,
  :auto_validation => true,
  :tagset => Markaby::XHTMLTransitional
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(assigns = {}, helpers = nil, &block) ⇒ Builder

Create a Markaby builder object. Pass in a hash of variable assignments to assigns which will be available as instance variables inside tag construction blocks. If an object is passed in to helpers, its methods will be available from those same blocks.

Pass in a block to new and the block will be evaluated.

mab = Markaby::Builder.new {
  html do
    body do
      h1 "Matching Mole"
    end
  end
}



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 61

def initialize(assigns = {}, helpers = nil, &block)
  @streams = [[]]
  @assigns = assigns
  @elements = {}

  @@default.each do |k, v|
    instance_variable_set("@#{k}", @assigns[k] || v)
  end

  if helpers.nil?
    @helpers = nil
  else
    @helpers = helpers.dup
    for iv in helpers.instance_variables
      instance_variable_set(iv, helpers.instance_variable_get(iv))
    end
  end

  unless assigns.nil? || assigns.empty?
    for iv, val in assigns
      instance_variable_set("@#{iv}", val)
      unless @helpers.nil?
        @helpers.instance_variable_set("@#{iv}", val)
      end
    end
  end

  @builder = ::Builder::XmlMarkup.new(:indent => @indent, :target => @streams.last)
  class << @builder
      attr_accessor :target, :level
  end

  if block
    text(capture(&block))
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(sym, *args, &block) ⇒ Object

This method is used to intercept calls to helper methods and instance variables. Here is the order of interception:

  • If sym is a helper method, the helper method is called and output to the stream.

  • If sym is a Builder::XmlMarkup method, it is passed on to the builder object.

  • If sym is also the name of an instance variable, the value of the instance variable is returned.

  • If sym has come this far and no tagset is found, sym and its arguments are passed to tag!

  • If a tagset is found, though, NoMethodError is raised.

method_missing used to be the lynchpin in Markaby, but it’s no longer used to handle HTML tags. See html_tag for that.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 177

def method_missing(sym, *args, &block)
  if @helpers.respond_to?(sym, true) && !self.class.ignored_helpers.include?(sym)
    r = @helpers.send(sym, *args, &block)
    if @output_helpers and r.respond_to? :to_str
      fragment { @builder << r }
    else
      r
    end
  elsif ::Builder::XmlMarkup.instance_methods.include?(sym.to_s) 
    @builder.__send__(sym, *args, &block)
  elsif instance_variables.include?("@#{sym}")
    instance_variable_get("@#{sym}")
  elsif @tagset.nil?
    tag!(sym, *args, &block)
  else
    raise NoMethodError, "no such method `#{sym}'"
  end
end

Instance Attribute Details

#output_helpers ⇒ Object

Returns the value of attribute output_helpers.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 44

def output_helpers
  @output_helpers
end

#tagset ⇒ Object

Returns the value of attribute tagset.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 44

def tagset
  @tagset
end

Class Method Details

.ignore_helpers(*helpers) ⇒ Object 



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 40

def self.ignore_helpers(*helpers) 
  ignored_helpers.concat helpers 
end

.ignored_helpers ⇒ Object 



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 36

def self.ignored_helpers 
  @@ignored_helpers ||= [] 
end

.set(option, value) ⇒ Object 



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 32

def self.set(option, value)
  @@default[option] = value
end

Instance Method Details

#_erbout ⇒ Object

Emulate ERB to satisfy helpers like form_for.



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# File 'lib/gems/markaby-0.5/lib/markaby/rails.rb', line 25

def _erbout; self end

#capture(&block) ⇒ Object

Captures the HTML code built inside the block. This is done by creating a new stream for the builder object, running the block and passing back its stream as a string.

>> Markaby::Builder.new.capture { h1 "TEST"; h2 "CAPTURE ME" }
=> "<h1>TITLE</h1>\n<h2>CAPTURE ME</h2>\n"



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 120

def capture(&block)
  @streams.push(builder.target = [])
  @builder.level += 1
  str = instance_eval(&block)
  str = @streams.last.join if @streams.last.any?
  @streams.pop
  @builder.level -= 1
  builder.target = @streams.last
  str
end

#content_for(name, &block) ⇒ Object

Content_for will store the given block in an instance variable for later use in another template or in the layout.

The name of the instance variable is content_for_<name> to stay consistent with @content_for_layout which is used by ActionView’s layouts.

Example:

content_for("header") do
  h1 "Half Shark and Half Lion"
end

If used several times, the variable will contain all the parts concatenated.



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# File 'lib/gems/markaby-0.5/lib/markaby/rails.rb', line 40

def content_for(name, &block)
  @helpers.assigns["content_for_#{name}"] =
    eval("@content_for_#{name} = (@content_for_#{name} || '') + capture(&block)")
end

#head(*args, &block) ⇒ Object

Builds a head tag. Adds a meta tag inside with Content-Type set to text/html; charset=utf-8.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 230

def head(*args, &block)
  tag!(:head, *args) do
    tag!(:meta, "http-equiv" => "Content-Type", "content" => "text/html; charset=utf-8") if @output_meta_tag
    instance_eval(&block)
  end
end

#html_tag(sym, *args, &block) ⇒ Object

Every HTML tag method goes through an html_tag call. So, calling div is equivalent to calling html_tag(:div). All HTML tags in Markaby’s list are given generated wrappers for this method.

If the @auto_validation setting is on, this method will check for many common mistakes which could lead to invalid XHTML.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 202

def html_tag(sym, *args, &block)
  if @auto_validation and @tagset.self_closing.include?(sym) and block
    raise InvalidXhtmlError, "the `\#{sym}' element is self-closing, please remove the block"
  end
  if args.empty? and block.nil? and not NO_PROXY.include?(sym)
    return CssProxy.new do |args, block|
      if @tagset.forms.include?(sym) and args.last.respond_to?(:to_hash) and args.last[:id]
        args.last[:name] ||= args.last[:id]
      end
      tag!(sym, *args, &block)
    end
  end
  if not @tagset.self_closing.include?(sym) and args.first.respond_to?(:to_hash)
    block ||= proc{}
  end
  tag!(sym, *args, &block)
end

#tag!(tag, *args, &block) ⇒ Object

Create a tag named tag. Other than the first argument which is the tag name, the arguments are the same as the tags implemented via method_missing.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 133

def tag!(tag, *args, &block)
  ele_id = nil
  if @auto_validation and @tagset
      if !@tagset.tagset.has_key?(tag)
          raise InvalidXhtmlError, "no element `#{tag}' for #{tagset.doctype}"
      elsif args.last.respond_to?(:to_hash)
          attrs = args.last.to_hash
          attrs.each do |k, v|
              atname = k.to_s.downcase.intern
              unless k =~ /:/ or @tagset.tagset[tag].include? atname
                  raise InvalidXhtmlError, "no attribute `#{k}' on #{tag} elements"
              end
              if atname == :id
                  ele_id = v.to_s
                  if @elements.has_key? ele_id
                      raise InvalidXhtmlError, "id `#{ele_id}' already used (id's must be unique)."
                  end
              end
          end
      end
  end
  if block
    str = capture &block
    block = proc { text(str) }
  end

  f = fragment { @builder.method_missing(tag, *args, &block) }
  @elements[ele_id] = f if ele_id
  f
end

#text(string) ⇒ Object Also known as: <<, concat

Write a string to the HTML stream without escaping it.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 104

def text(string)
  @builder << "#{string}"
  nil
end

#to_s ⇒ Object

Returns a string containing the HTML stream. Internally, the stream is stored as an Array.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 99

def to_s
  @streams.last.to_s
end

#xhtml_strict(&block) ⇒ Object

Builds an html tag with XHTML 1.0 Strict doctype instead.



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 246

def xhtml_strict(&block)
  self.tagset = Markaby::XHTMLStrict
  xhtml_html &block
end

#xhtml_transitional(&block) ⇒ Object

Builds an html tag. An XML 1.0 instruction and an XHTML 1.0 Transitional doctype are prepended. Also assumes :xmlns => "http://www.w3.org/1999/xhtml", :lang => "en".



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# File 'lib/gems/markaby-0.5/lib/markaby/builder.rb', line 240

def xhtml_transitional(&block)
  self.tagset = Markaby::XHTMLTransitional
  xhtml_html &block
end