
-(+Number1, +Number2, -Result)

   Evaluates the difference Number1 - Number2 and unifies the resulting value
with Result.



Arguments
   Number1             A number.
   Number2             A number.
   Result              Output: a number.

Type
   Arithmetic

Description
   This predicate is used by the ECLiPSe compiler to expand evaluable
   arithmetic expressions.  So the call to -(Number1, Number2, Result) is
   equivalent to

    Result is Number1 - Number2

    which should be preferred for portability.

   The result is of type breal if any of the arguments is a breal,
   else float if any of the arguments is a float, else rational if any
   of the arguments is a rational.  Only when both arguments are
   integers is the result an integer.


   In coroutining mode, if Number1 or Number2 are uninstantiated, the call
   to -/3 is delayed until these variables are instantiated.




Modes and Determinism
   -(+, +, -) is det

Exceptions
     4 --- Number1 or Number2 is not instantiated (non-coroutining mode    only).
    24 --- Number1 or Number2 is not of a numeric type.

Examples
   
    Result is 5 - 2.            % gives Result = 3
    Result is 5 - -2.0.         % gives Result = 7.0


See Also
   is / 2
