class Builder::XmlMarkup

Create XML markup easily. All (well, almost all) methods sent to an XmlMarkup object will be translated to the equivalent XML markup. Any method with a block will be treated as an XML markup tag with nested markup in the block.

Examples will demonstrate this easier than words. In the following, xm is an XmlMarkup object.

xm.em("emphasized")            # => <em>emphasized</em>
xm.em { xm.b("emp & bold") }   # => <em><b>emph &amp; bold</b></em>
xm.a("A Link", "href"=>"http://onestepback.org")
                               # => <a href="http://onestepback.org">A Link</a>
xm.div { xm.br }               # => <div><br/></div>
xm.target("name"=>"compile", "option"=>"fast")
                               # => <target option="fast" name="compile"\>
                               # NOTE: order of attributes is not specified.

xm.instruct!                   # <?xml version="1.0" encoding="UTF-8"?>
xm.html {                      # <html>
  xm.head {                    #   <head>
    xm.title("History")        #     <title>History</title>
  }                            #   </head>
  xm.body {                    #   <body>
    xm.comment! "HI"           #     <!-- HI -->
    xm.h1("Header")            #     <h1>Header</h1>
    xm.p("paragraph")          #     <p>paragraph</p>
  }                            #   </body>
}                              # </html>

Notes:

Public Class Methods

new(options={}) click to toggle source

Create an XML markup builder. Parameters are specified by an option hash.

:target => target_object

Object receiving the markup. target_object must respond to the <<(a_string) operator and return itself. The default target is a plain string target.

:indent => indentation

Number of spaces used for indentation. The default is no indentation and no line breaks.

:margin => initial_indentation_level

Amount of initial indentation (specified in levels, not spaces).

:quote => :single

Use single quotes for attributes rather than double quotes.

:escape_attrs => OBSOLETE

The :escape_attrs option is no longer supported by builder (and will be quietly ignored). String attribute values are now automatically escaped. If you need unescaped attribute values (perhaps you are using entities in the attribute values), then give the value as a Symbol. This allows much finer control over escaping attribute values.

Calls superclass method Builder::XmlBase.new
# File lib/builder/xmlmarkup.rb, line 189
def initialize(options={})
  indent = options[:indent] || 0
  margin = options[:margin] || 0
  @quote = (options[:quote] == :single) ? "'" : '"'
  @explicit_nil_handling = options[:explicit_nil_handling]
  super(indent, margin)
  @target = options[:target] || ""
end

Public Instance Methods

cdata!(text) click to toggle source

Insert a CDATA section into the XML markup.

For example:

xml.cdata!("text to be included in cdata")
    #=> <![CDATA[text to be included in cdata]]>
# File lib/builder/xmlmarkup.rb, line 269
def cdata!(text)
  _ensure_no_block ::Kernel::block_given?
  _special("<![CDATA[", "]]>", text.gsub(']]>', ']]]]><![CDATA[>'), nil)
end
comment!(comment_text) click to toggle source
# File lib/builder/xmlmarkup.rb, line 203
def comment!(comment_text)
  _ensure_no_block ::Kernel::block_given?
  _special("<!-- ", " -->", comment_text, nil)
end
declare!(inst, *args, &block) click to toggle source

Insert an XML declaration into the XML markup.

For example:

xml.declare! :ELEMENT, :blah, "yada"
    # => <!ELEMENT blah "yada">
# File lib/builder/xmlmarkup.rb, line 214
def declare!(inst, *args, &block)
  _indent
  @target << "<!#{inst}"
  args.each do |arg|
    case arg
    when ::String
      @target << %Q{ "#{arg}"} # " WART
    when ::Symbol
      @target << " #{arg}"
    end
  end
  if ::Kernel::block_given?
    @target << " ["
    _newline
    _nested_structures(block)
    @target << "]"
  end
  @target << ">"
  _newline
end
instruct!(directive_tag=:xml, attrs={}) click to toggle source

Insert a processing instruction into the XML markup. E.g.

For example:

xml.instruct!
    #=> <?xml version="1.0" encoding="UTF-8"?>
xml.instruct! :aaa, :bbb=>"ccc"
    #=> <?aaa bbb="ccc"?>

Note: If the encoding is setup to “UTF-8” and the value of $KCODE is “UTF8”, then builder will emit UTF-8 encoded strings rather than the entity encoding normally used.

# File lib/builder/xmlmarkup.rb, line 247
def instruct!(directive_tag=:xml, attrs={})
  _ensure_no_block ::Kernel::block_given?
  if directive_tag == :xml
    a = { :version=>"1.0", :encoding=>"UTF-8" }
    attrs = a.merge attrs
    @encoding = attrs[:encoding].downcase
  end
  _special(
    "<?#{directive_tag}",
    "?>",
    nil,
    attrs,
    [:version, :encoding, :standalone])
end
target!() click to toggle source

Return the target of the builder.

# File lib/builder/xmlmarkup.rb, line 199
def target!
  @target
end

Private Instance Methods

_attr_value(value) click to toggle source
# File lib/builder/xmlmarkup.rb, line 320
def _attr_value(value)
  case value
  when ::Symbol
    value.to_s
  else
    _escape_attribute(value.to_s)
  end
end
_end_tag(sym) click to toggle source

Insert an ending tag.

# File lib/builder/xmlmarkup.rb, line 304
def _end_tag(sym)
  @target << "</#{sym}>"
end
_ensure_no_block(got_block) click to toggle source
# File lib/builder/xmlmarkup.rb, line 329
def _ensure_no_block(got_block)
  if got_block
    ::Kernel::raise IllegalBlockError.new(
      "Blocks are not allowed on XML instructions"
    )
  end
end
_insert_attributes(attrs, order=[]) click to toggle source

Insert the attributes (given in the hash).

# File lib/builder/xmlmarkup.rb, line 309
def _insert_attributes(attrs, order=[])
  return if attrs.nil?
  order.each do |k|
    v = attrs[k]
    @target << %Q{ #{k}=#{@quote}#{_attr_value(v)}#{@quote}} if v
  end
  attrs.each do |k, v|
    @target << %Q{ #{k}=#{@quote}#{_attr_value(v)}#{@quote}} unless order.member?(k) # " WART
  end
end
_special(open, close, data=nil, attrs=nil, order=[]) click to toggle source

Insert special instruction.

# File lib/builder/xmlmarkup.rb, line 285
def _special(open, close, data=nil, attrs=nil, order=[])
  _indent
  @target << open
  @target << data if data
  _insert_attributes(attrs, order) if attrs
  @target << close
  _newline
end
_start_tag(sym, attrs, end_too=false) click to toggle source

Start an XML tag. If end_too is true, then the start tag is also the end tag (e.g. <br/>

# File lib/builder/xmlmarkup.rb, line 296
def _start_tag(sym, attrs, end_too=false)
  @target << "<#{sym}"
  _insert_attributes(attrs)
  @target << "/" if end_too
  @target << ">"
end
_text(text) click to toggle source

Insert text directly in to the builder's target.

# File lib/builder/xmlmarkup.rb, line 280
def _text(text)
  @target << text
end