
-(+Number1, +Number2, -Result)

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



Arguments
   Number1             A number.
   Number2             A number.
   Result              A variable or 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
   
Success:
      -(5, 2, 3).            (gives Result = 3)
      -(5, -2.0, Result).    (gives Result = 7.0)
Fail:
      -(1, 2, 3).
      -(1, 2, 3.0).
      -(5, 2, r).
Error:
      -(A, 2, 6).             (Error 4).
      -(4 + 1, 2, 3).         (Error 24).





See Also
   is / 2
