+ (find-if #'(lambda (f) (string= filename (fil f))) *umls-files*))
+
+(defvar *position-hash* (make-hash-table :test 'equal))
+
+(defun position-field-file (filename fieldname)
+ "Returns the position of a field in a file"
+ (let ((key (cons filename fieldname)))
+ (multiple-value-bind (pos found) (gethash key *position-hash*)
+ (if found
+ (return-from position-field-file pos)))
+
+ (let ((ufile (find-ufile filename)))
+ (unless ufile
+ (warn "Unable to find ufile for filename ~A." filename)
+ (return-from position-field-file nil))
+ (let ((pos (position fieldname (fields ufile) :test #'string=)))
+ (unless pos
+ (warn "Unable to find field ~A in ufile ~S." fieldname ufile)
+ (return-from position-field-file nil))
+ (setf (gethash key *position-hash*) pos)
+ pos))))