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 { xmm.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 { 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.h1("Header")            #     <h1>Header</h1>
      xm.p("paragraph")          #     <p>paragraph</p>
    }                            #   </body>
  }                              # </html>

Notes:

The order that attributes are inserted in markup tags is undefined.

Sometimes you wish to insert text without enclosing tags. Use the text! method to accomplish this.

Example:

  xm.div {                          # <div>
    xm.text! "line"; xm.br          #   line<br/>
    xm.text! "another line"; xmbr   #    another line<br/>
  }                                 # </div>

The special XML characters <, >, and & are converted to <, > and & automatically. Use the << operation to insert text without modification.
Sometimes tags use special characters not allowed in ruby identifiers. Use the tag! method to handle these cases.
Example:
```
  xml.tag!("SOAP:Envelope") { ... }
```
will produce …
```
  <SOAP:Envelope> ... </SOAP:Envelope>"
```
tag! will also take text and attribute arguments (after the tag name) like normal markup methods. (But see the next bullet item for a better way to handle XML namespaces).
Direct support for XML namespaces is now available. If the first argument to a tag call is a symbol, it will be joined to the tag to produce a namespace:tag combination. It is easier to show this than describe it.
```
  xml.SOAP :Envelope do ... end
```
Just put a space before the colon in a namespace to produce the right form for builder (e.g. "SOAP:Envelope" => "xml.SOAP :Envelope")

XmlMarkup builds the markup in any object (called a target) that accepts the << method. If no target is given, then XmlMarkup defaults to a string target.

Examples:

  xm = Builder::XmlMarkup.new
  result = xm.title("yada")
  # result is a string containing the markup.

  buffer = ""
  xm = Builder::XmlMarkup.new(buffer)
  # The markup is appended to buffer (using <<)

  xm = Builder::XmlMarkup.new(STDOUT)
  # The markup is written to STDOUT (using <<)

  xm = Builder::XmlMarkup.new
  x2 = Builder::XmlMarkup.new(:target=>xm)
  # Markup written to +x2+ will be send to +xm+.

Indentation is enabled by providing the number of spaces to indent for each level as a second argument to XmlBuilder.new. Initial indentation may be specified using a third parameter.

Example:

  xm = Builder.new(:ident=>2)
  # xm will produce nicely formatted and indented XML.

  xm = Builder.new(:indent=>2, :margin=>4)
  # xm will produce nicely formatted and indented XML with 2
  # spaces per indent and an over all indentation level of 4.

  builder = Builder::XmlMarkup.new(:target=>$stdout, :indent=>2)
  builder.name { |b| b.first("Jim"); b.last("Weirich) }
  # prints:
  #     <name>
  #       <first>Jim</first>
  #       <last>Weirich</last>
  #     </name>

The instance_eval implementation which forces self to refer to the message receiver as self is now obsolete. We now use normal block calls to execute the markup block. This means that all markup methods must now be explicitly send to the xml builder. For instance, instead of
```
   xml.div { strong("text") }
```
you need to write:
```
   xml.div { xml.strong("text") }
```
Although more verbose, the subtle change in semantics within the block was found to be prone to error. To make this change a little less cumbersome, the markup block now gets the markup object sent as an argument, allowing you to use a shorter alias within the block.

For example:
```
  xml_builder = Builder::XmlMarkup.new
  xml_builder.div { |xml|
    xml.strong("text")
  }
```

Methods

_attr_value _end_tag _ensure_no_block _insert_attributes _special _start_tag _text cdata! comment! declare! instruct! new target!

Public Class methods

new(options={})

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

:target=>target_object:	Object receiving the markup. `out` must respond to the `<<` operator. The default 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).
:escape_attrs=><b>OBSOLETE</em>:	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.

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 184
    def initialize(options={})
      indent = options[:indent] || 0
      margin = options[:margin] || 0
      super(indent, margin)
      @target = options[:target] || ""
    end

Public Instance methods

cdata!(text)

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]]>

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 258
    def cdata!(text)
      _ensure_no_block block_given?
      _special("<![CDATA[", "]]>", text, nil)
    end

comment!(comment_text)

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 196
    def comment!(comment_text)
      _ensure_no_block block_given?
      _special("<!-- ", " -->", comment_text, nil)
    end

declare!(inst, *args, &block)

Insert an XML declaration into the XML markup.

For example:

  xml.declare! :ELEMENT, :blah, "yada"
      # => <!ELEMENT blah "yada">

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 207
    def declare!(inst, *args, &block)
      _indent
      @target << "<!#{inst}"
      args.each do |arg|
  case arg
  when String
    @target << %{ "#{arg}"}
  when Symbol
    @target << " #{arg}"
  end
      end
      if block_given?
  @target << " ["
  _newline
  _nested_structures(block)
  @target << "]"
      end
      @target << ">"
      _newline
    end

instruct!(directive_tag=:xml, attrs={})

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"?>

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 237
    def instruct!(directive_tag=:xml, attrs={})
      _ensure_no_block block_given?
      if directive_tag == :xml
  a = { :version=>"1.0", :encoding=>"UTF-8" }
  attrs = a.merge attrs
      end
      _special(
  "<?#{directive_tag}",
  "?>",
  nil,
  attrs,
  [:version, :encoding, :standalone])
    end

target!()

Return the target of the builder.

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 192
    def target!
      @target
    end

Private Instance methods

_attr_value(value)

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 309
    def _attr_value(value)
      case value
      when Symbol
  value.to_s
      else
  _escape_quote(value.to_s)
      end
    end

_end_tag(sym)

Insert an ending tag.

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 293
    def _end_tag(sym)
      @target << "</#{sym}>"
    end

_ensure_no_block(got_block)

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 318
    def _ensure_no_block(got_block)
      if got_block
  fail IllegalBlockError,
    "Blocks are not allowed on XML instructions"
      end
    end

_insert_attributes(attrs, order=[])

Insert the attributes (given in the hash).

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 298
    def _insert_attributes(attrs, order=[])
      return if attrs.nil?
      order.each do |k|
  v = attrs[k]
  @target << %{ #{k}="#{_attr_value(v)}"} if v
      end
      attrs.each do |k, v|
  @target << %{ #{k}="#{_attr_value(v)}"} unless order.member?(k)
      end
    end

_special(open, close, data=nil, attrs=nil, order=[])

Insert special instruction.

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 274
    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)

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

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 285
    def _start_tag(sym, attrs, end_too=false)
      @target << "<#{sym}"
      _insert_attributes(attrs)
      @target << "/" if end_too
      @target << ">"
    end

_text(text)

Insert text directly in to the builder’s target.

[Source]

# File activesupport/lib/active_support/vendor/builder/xmlmarkup.rb, line 269
    def _text(text)
      @target << text
    end