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.comment! "HI"           #     <!-- HI -->
      xm.h1("Header")            #     <h1>Header</h1>
      xm.p("paragraph")          #     <p>paragraph</p>
    }                            #   </body>
  }                              # </html>

Notes:

 
    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>

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. 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=>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.

     # File lib/builder/xmlmarkup.rb, line 185
185:     def initialize(options={})
186:       indent = options[:indent] || 0
187:       margin = options[:margin] || 0
188:       super(indent, margin)
189:       @target = options[:target] || ""
190:     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 259
259:     def cdata!(text)
260:       _ensure_no_block block_given?
261:       _special("<![CDATA[", "]]>", text, nil)
262:     end
comment!(comment_text) click to toggle source
     # File lib/builder/xmlmarkup.rb, line 197
197:     def comment!(comment_text)
198:       _ensure_no_block block_given?
199:       _special("<!-- ", " -->", comment_text, nil)
200:     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 208
208:     def declare!(inst, *args, &block)
209:       _indent
210:       @target << "<!#{inst}"
211:       args.each do |arg|
212:         case arg
213:         when String
214:           @target << %{ "#{arg}"} # " WART
215:         when Symbol
216:           @target << " #{arg}"
217:         end
218:       end
219:       if block_given?
220:         @target << " ["
221:         _newline
222:         _nested_structures(block)
223:         @target << "]"
224:       end
225:       @target << ">"
226:       _newline
227:     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"?>
     # File lib/builder/xmlmarkup.rb, line 238
238:     def instruct!(directive_tag=:xml, attrs={})
239:       _ensure_no_block block_given?
240:       if directive_tag == :xml
241:         a = { :version=>"1.0", :encoding=>"UTF-8" }
242:         attrs = a.merge attrs
243:       end
244:       _special(
245:       "<?#{directive_tag}",
246:       "?>",
247:       nil,
248:       attrs,
249:       [:version, :encoding, :standalone])
250:     end
target!() click to toggle source

Return the target of the builder.

     # File lib/builder/xmlmarkup.rb, line 193
193:     def target!
194:       @target
195:     end

Private Instance Methods

_attr_value(value) click to toggle source
     # File lib/builder/xmlmarkup.rb, line 310
310:     def _attr_value(value)
311:       case value
312:       when Symbol
313:         value.to_s
314:       else
315:         _escape_quote(value.to_s)
316:       end
317:     end
_end_tag(sym) click to toggle source

Insert an ending tag.

     # File lib/builder/xmlmarkup.rb, line 294
294:     def _end_tag(sym)
295:       @target << "</#{sym}>"
296:     end
_ensure_no_block(got_block) click to toggle source
     # File lib/builder/xmlmarkup.rb, line 319
319:     def _ensure_no_block(got_block)
320:       if got_block
321:         fail IllegalBlockError,
322:         "Blocks are not allowed on XML instructions"
323:       end
324:     end
_insert_attributes(attrs, order=[]) click to toggle source

Insert the attributes (given in the hash).

     # File lib/builder/xmlmarkup.rb, line 299
299:     def _insert_attributes(attrs, order=[])
300:       return if attrs.nil?
301:       order.each do |k|
302:         v = attrs[k]
303:         @target << %{ #{k}="#{_attr_value(v)}"} if v # " WART
304:       end
305:       attrs.each do |k, v|
306:         @target << %{ #{k}="#{_attr_value(v)}"} unless order.member?(k) # " WART
307:       end
308:     end
_special(open, close, data=nil, attrs=nil, order=[]) click to toggle source

Insert special instruction.

     # File lib/builder/xmlmarkup.rb, line 275
275:     def _special(open, close, data=nil, attrs=nil, order=[])
276:       _indent
277:       @target << open
278:       @target << data if data
279:       _insert_attributes(attrs, order) if attrs
280:       @target << close
281:       _newline
282:     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.

     # File lib/builder/xmlmarkup.rb, line 286
286:     def _start_tag(sym, attrs, end_too=false)
287:       @target << "<#{sym}"
288:       _insert_attributes(attrs)
289:       @target << "/" if end_too
290:       @target << ">"
291:     end
_text(text) click to toggle source

Insert text directly in to the builder’s target.

     # File lib/builder/xmlmarkup.rb, line 270
270:     def _text(text)
271:       @target << text
272:     end

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