anchor.diff:  ;;;
   ;;; This AST is used for adding two values of type SINGLE-FLOAT.
   ;;;
  -;;; It can be used by an implementation that supports the SINGLE-FLOAT
  -;;; data type.
  -;;;
   ;;; Both inputs must be of type SINGLE-FLOAT, so in safe code this
   ;;; restriction has to be checked before this AST is evaluated. 
   
  
positive.code: ;;;
  ;;; This AST is used for multiplying two values of type SINGLE-FLOAT.
  ;;;
  ;;; It can be used by an implementation that supports the SINGLE-FLOAT
  ;;; data type.  
  ;;;
  ;;; Both inputs must be of type SINGLE-FLOAT, so in safe code this
  ;;; restriction has to be checked before this AST is evaluated. 
  
  
negative.code: ;;; requires both its arguments to be of type SINGLE-FLOAT.  It can
  ;;; only occur as the TEST-AST of an IF-AST.  If this AST occurs in a
  ;;; position where a value is required, an error is signaled.
  
  (make-float-ast single-float-greater-ast)
  
  