anchor.diff:      "expl"  "dislocated"
       "advcl" "advmod"
       "discourse"
  -    "aux" "cop"
  -    "mark" "nmod"
  -    "appos"
  +    "aux"  "cop"
  +    "mark" "nmod" "appos"
       "nummod"
       "acl"
       "amod"
  
positive.code:   "Attachment score by sentence (macro-average).
  
     The attachment score is the percentage of words that have correct
     arcs to their heads.
  
     The unlabeled attachment score (UAS) considers only who is the head
     of the token, while the labeled attachment score (LAS) considers
     both the head and the arc label (dependency label / syntactic class).
  
     References:
       - Dependency Parsing - Kubler, Mcdonald and Nivre (pp.79-80)"
    (let ((ns (mapcar #'(lambda (x y)
  			(- (float 1)
  			   (/ (length (sentence-diff x y :fields fields
  						     :punct punct
  						     :simple-dep simple-dep))
  			      (sentence-size y))))
  		    list-sent1
  		    list-sent2)))
      (/ (apply #'+ ns) (float (length ns)))))
  
  
  (defun attachment-score-by-word (list-sent1 list-sent2 &key (fields *token-fields*)
  							 (punct t) (simple-dep nil))
    "Attachment score by word (micro-average).
  
     The attachment score is the percentage of words that have correct
     arcs to their heads.
  
     The unlabeled attachment score (UAS) considers only who is the head
     of the token, while the labeled attachment score (LAS) considers
     both the head and the arc label (dependency label / syntactic class).
  
     References:
       - Dependency Parsing - Kubler, Mcdonald and Nivre (pp.79-80)"
  
negative.code: 				     list-sent2)
  			     :key #'length
  			     :initial-value 0)))
      (- 1.0 (/ wrong-words total-words))))
  	
  
  
  (defun recall (list-sent1 list-sent2 deprel &key (head-error nil) (label-error t) (simple-deprel nil))
  