Module: Ariel::LabelUtils

Defined in:
lib/ariel/label_utils.rb

Overview

A set of methods for use when dealing with strings from labeled documents.

Constant Summary collapse

S_LABEL = 
"<"
E_LABEL = 
">"

Class Method Summary collapse

Class Method Details

.any_label_regex ⇒ Object

Helper function that returns a regex that will match any open or closing label tags.

[View source]

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# File 'lib/ariel/label_utils.rb', line 20

def self.any_label_regex()
  Regexp.union(*self.label_regex)
end

.clean_string(string) ⇒ Object

Removes all labels such as <l:title> from the given string and returns the result.

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# File 'lib/ariel/label_utils.rb', line 26

def self.clean_string(string)
  string.gsub self.any_label_regex, ''
end

.extract_labeled_region(structure, parent_extracted_node) ⇒ Object

Extracts the labeled region representing the given structure node from the parent_extracted_node. A new Node::Extracted is returned to be added as a child to the parent_extracted_node. Used when loading labeled documents.

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# File 'lib/ariel/label_utils.rb', line 33

def self.extract_labeled_region(structure, parent_extracted_node)
  tokenstream=parent_extracted_node.tokenstream
  start_idxs=[]
  end_idxs=[]
  tokenstream.rewind
  while start_idx = self.skip_to_label_tag(tokenstream, structure.node_name, :open)
    start_idxs << start_idx
    break unless structure.node_type==:list_item
  end
  tokenstream.rewind
  while end_idx=self.skip_to_label_tag(tokenstream, structure.node_name, :closed)
    end_idxs << (end_idx -2) #rewind to token before the label tag token
    break unless structure.node_type==:list_item
  end
  result=[]
  i=0
  start_idxs.zip(end_idxs) do |start_idx, end_idx|
    if start_idx && end_idx && (start_idx <= end_idx)
      newstream=tokenstream.slice_by_token_index(start_idx, end_idx)
      if structure.node_type==:list_item
        new_name="#{structure.node_name}_#{i}"
        i+=1
      else
        new_name = structure.node_name
      end
      child_node = Node::Extracted.new(new_name, newstream, structure)
      result << child_node
      parent_extracted_node.add_child child_node
      yield child_node if block_given?
    else
      break
    end
  end
  return result
end

.label_regex(tag_contents = '\w+', namespace = 'l') ⇒ Object

Returns an array containing a pair of regular expressions to match a start label tag and an end label tag. If the tag_contents is not modified the regular expressions will return any properly formatted label tag. The namespace to search for can also be modified. The returned regular expressions are case insensitive.

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# File 'lib/ariel/label_utils.rb', line 13

def self.label_regex(tag_contents='\w+', namespace='l')
  [/#{S_LABEL}#{namespace}:#{tag_contents}#{E_LABEL}/i,
  /#{S_LABEL}\/#{namespace}:#{tag_contents}#{E_LABEL}/i]
end