Class: TagTreeScanner

Inherits:
Object
  • Object
show all
Defined in:
lib/tagtreescanner.rb

Overview

Overview

The TagTreeScanner class provides a generic framework for creating a nested hierarchy of tags and text (like XML or HTML) by parsing text. An example use (and the reason it was written) is to convert a wiki markup syntax into HTML.

See the README.txt.html file for examples and more information.

Defined Under Namespace

Classes: Tag, TagFactory, TextNode

Constant Summary collapse

VERSION = 
"0.8.1"

Class Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(string_to_parse) ⇒ TagTreeScanner

Scans through string_to_parse and builds a tree of tags based on the regular expressions and rules set by the TagFactory instances present in @tag_genres.

After parsing the tree, call #to_xml or #to_html to retrieve a string representation.



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# File 'lib/tagtreescanner.rb', line 604

def initialize( string_to_parse )
  current = @root = self.class.root_factory.create
  tag_genres = self.class.tag_genres
  text_match = self.class.text_match

  ss = StringScanner.new( string_to_parse )
  while !ss.eos?
    # Keep popping off the current tag until we get to the root,
    # as long as the end criteria is met
    while ( current != @root ) && (!current.close_requires_bol? || ss.bol?) && ss.scan( current.close_match )
      current = current.parent_tag || @root
    end

    # No point in continuing if closing out tags consumed the rest of the string
    break if ss.eos?

    # Look for a tag to open
    if factories = tag_genres[ current.allowed_genre ]
      tag = nil
      factories.each{ |factory|
        if tag = factory.match( ss, self )
          current.append_child( tag )
          current = tag unless tag.autoclose?
          break
        end
      }
      #start at the top of the loop if we found one
      next if tag
    end

    # Couldn't find a valid tag at this spot
    # so we need to eat some characters
    consumed = ss.scan( text_match )
    current << consumed if current.allows_text?
  end
end

Class Attribute Details

.root_factory ⇒ Object

Returns the value of attribute root_factory.



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# File 'lib/tagtreescanner.rb', line 567

def root_factory
  @root_factory
end

.tag_genres ⇒ Object

Returns the value of attribute tag_genres.



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# File 'lib/tagtreescanner.rb', line 567

def tag_genres
  @tag_genres
end

.text_match ⇒ Object

Returns the value of attribute text_match.



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# File 'lib/tagtreescanner.rb', line 567

def text_match
  @text_match
end

Class Method Details

.inherited(child_class) ⇒ Object

When a class inherits from TagTreeScanner, defaults are set for @tag_genres, @root_factory and @text_match



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# File 'lib/tagtreescanner.rb', line 677

def self.inherited( child_class ) #:nodoc:
  child_class.tag_genres = @tag_genres
  child_class.root_factory = @root_factory
  child_class.text_match = @text_match
end

Instance Method Details

#inspect ⇒ Object

Returns a hierarchical representation of the entire tag tree



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# File 'lib/tagtreescanner.rb', line 670

def inspect #:nodoc:
  @root.to_hier
end

#tags ⇒ Object

Returns an array of all root-level tags found



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# File 'lib/tagtreescanner.rb', line 659

def tags
  @root.child_tags
end

#tags_by_name(name) ⇒ Object

Returns an array of all tags in the tree whose Tag#name matches the supplied name.



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# File 'lib/tagtreescanner.rb', line 665

def tags_by_name( name )
  @root.tags_by_type( name )
end

#to_html ⇒ Object

Returns an HTML representation of the tag tree.

This is the same as the #to_xml method except that empty tags use an explicit close tag, e.g. <div></div> versus <div />



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# File 'lib/tagtreescanner.rb', line 645

def to_html
  @root.child_tags.inject(''){ |out, tag| out << tag.to_html }
end

#to_xml ⇒ Object

Returns an XML representation of the tag tree.

This method is the same as the #to_html method except that empty tags do not use an explicit close tag, e.g. <div /> versus <div></div>



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# File 'lib/tagtreescanner.rb', line 654

def to_xml
  @root.child_tags.inject(''){ |out, tag| out << tag.to_xml }
end