Class: Markaby::Builder

Inherits:
Object
  • Object
show all
Includes:
BuilderTags
Defined in:
lib/markaby/builder.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

Direct Known Subclasses

Rails::Builder

Constant Summary collapse

DEFAULT_OPTIONS = 
{
  :indent                 => 0,
  :output_helpers         => true,
  :output_xml_instruction => true,
  :output_meta_tag        => true,
  :auto_validation        => true,
  :tagset                 => Markaby::XHTMLTransitional,
  :root_attributes => {
    :xmlns      => 'http://www.w3.org/1999/xhtml',
    :'xml:lang' => 'en',
    :lang       => 'en'
  }
}
@@options = 
DEFAULT_OPTIONS.dup

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from BuilderTags

#head, #html_tag, #xhtml_frameset, #xhtml_strict, #xhtml_transitional

Constructor Details

#initialize(assigns = {}, helper = 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 helper, 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/markaby/builder.rb', line 78

def initialize(assigns = {}, helper = nil, &block)
  @streams = [[]]
  @assigns = assigns.dup
  @_helper = helper
  @used_ids = {}

  @@options.each do |k, v|
    instance_variable_set("@#{k}", @assigns.delete(k) || v)
  end
  
  @assigns.each do |k, v|
    instance_variable_set("@#{k}", v)
  end

  @builder = XmlMarkup.new(:indent => @indent, :target => @streams.last)

  instance_eval(&block) if block
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

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

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/markaby/builder.rb', line 202

def method_missing(sym, *args, &block)
  if @_helper.respond_to?(sym, true) && !self.class.ignored_helpers.include?(sym)
    r = @_helper.send(sym, *args, &block)
    if @output_helpers && r.respond_to?(:to_str)
      fragment { @builder << r }
    else
      r
    end
  elsif @assigns.has_key?(sym)
    @assigns[sym]
  elsif @assigns.has_key?(stringy_key = sym.to_s)
    # Rails' ActionView assigns hash has string keys for
    # instance variables that are defined in the controller.
    @assigns[stringy_key]
  elsif instance_variables.include?(ivar = "@#{sym}")
    instance_variable_get(ivar)
  elsif @_helper && @_helper.instance_variables.include?(ivar)
    @_helper.instance_variable_get(ivar)
  elsif ::Builder::XmlMarkup.instance_methods.include?(sym.to_s)
    @builder.__send__(sym, *args, &block)
  elsif !@tagset
    tag!(sym, *args, &block)
  else
    super
  end
end

Instance Attribute Details

#output_helpers ⇒ Object

Returns the value of attribute output_helpers.



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

def output_helpers
  @output_helpers
end

#tagset ⇒ Object

Returns the value of attribute tagset.



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

def tagset
  @tagset
end

Class Method Details

.get(option) ⇒ Object 



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# File 'lib/markaby/builder.rb', line 49

def self.get(option)
  @@options[option]
end

.ignore_helpers(*helpers) ⇒ Object 



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# File 'lib/markaby/builder.rb', line 57

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

.ignored_helpers ⇒ Object 



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# File 'lib/markaby/builder.rb', line 53

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

.restore_defaults! ⇒ Object 



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# File 'lib/markaby/builder.rb', line 41

def self.restore_defaults!
  @@options = DEFAULT_OPTIONS.dup
end

.set(option, value) ⇒ Object 



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# File 'lib/markaby/builder.rb', line 45

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

Instance Method Details

#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/markaby/builder.rb', line 137

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

#helper=(helper) ⇒ Object 



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# File 'lib/markaby/builder.rb', line 97

def helper=(helper)
  @_helper = helper
end

#locals=(locals) ⇒ Object 



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# File 'lib/markaby/builder.rb', line 108

def locals=(locals)
  locals.each do |key, value|
    metaclass do
      define_method key do
        value
      end
    end
  end
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/markaby/builder.rb', line 150

def tag!(tag, *args, &block)
  ele_id = nil
  if @auto_validation && @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

      if @tagset.forms.include?(tag) && attrs[:id]
        attrs[:name] ||= attrs[:id]
      end
          
      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 @used_ids.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) }
  @used_ids[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/markaby/builder.rb', line 124

def text(string)
  @builder << string.to_s
  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/markaby/builder.rb', line 119

def to_s
  @streams.last.to_s
end