anchor.diff:      (funcall function)))
   
   (defmacro with-form (form &body body)
  +  "Bind *FORM* to FORM and evaluate BODY in that context."
     `(call-with-form ,form (lambda () ,@body)))
   
   (defmacro defform (form-name args fields)
  
positive.code:     (funcall function)))
  
  (defmacro with-form-renderer (renderer &body body)
    `(call-with-form-renderer ,renderer (lambda () ,@body)))
  
  (defun call-with-form-theme (form-theme function)
  
negative.code:       (funcall function))))
  
  (defmacro with-form-theme (form-theme &body body)
    "Bind *FORM-THEME* to FORM-THEME and evaluate BODY in that context."
    `(call-with-form-theme ,form-theme (lambda () ,@body)))
  
  (defun call-with-form (form function)
  