[ Arithmetic | The ECLiPSe Built-In Predicates | Reference Manual | Alphabetic Index ]

+Expr1 =< +Expr2

Succeed if the value of Expr1 is less than or equal to the value of Expr2.
Expr1
An arithmetic expression
Expr2
An arithmetic expression

Description

Both arguments are evaluated and their types adjusted. Then the resulting numbers are compared. The predicate succeeds if the value of Expr1 is less than or equal to the value of Expr2. If the system is in coroutining mode and the arguments are not ground, this predicate delays until the expressions are fully instantiated.

The predicate also delays when the comparison involves bounded reals, and the compared values overlap such that the result is undecidable.

Modes and Determinism

Modules

This predicate is sensitive to its module context (tool predicate, see @/1).

Fail Conditions

fails if the value of Expr1 is greater than the value of Expr2

Exceptions

(4) instantiation fault
Expr1 or Expr2 is a variable (non-coroutining mode only).
(5) type error
Expr1 or Expr2 is not an arithmetic expression.

Examples

   Success:
   5 - 3 =< 6 / 2.
   1 =< sin(pi/2).      % 1 converted to 1.0
   Fail:
   2 + 5 =< 2 * 3.
   Error:
   _ =< 10.              (Error 4)
   "s" =< 10.            (Error 5)



See Also

colgen : =< / 2, suspend : =< / 2, ic : =< / 2, eplex : =< / 2, is / 2, =:= / 2, =\= / 2, >= / 2, < / 2, > / 2