binary_condition.md
In rswipl: Embed 'SWI'-'Prolog'

class binary_condition {#class-binary_condition}

Class binary_condition is a super class for the various arithmetic condition statements:

| <  | Test <-left to be less than <-right                |
| =< | Test <-left to be less than or equal to <-right    |
| =  | Test <-left to be equal to <-right                 |
| >= | Test <-left to be greater than or equal to <-right |
| >  | Test <-left to be greater than <-right             |

These code objects are almost exclusively used in conditions for if objects and friends. When executed, the subclasses of binary_condition evaluates <-left and <-right to a numeric value and compares the two according to the class.

The type-check of a binary_condition is expression. Type expression is a disjunction of the following types:

| int      | XPCE integers                                 |
| number   | number object                                 |
| real     | real object                                   |
| function | function object (including @arg1 and class ?) |

The following example defines that the pointer should be in the positive part of the coordinate system of the receiving graphical:

and(@event?x > 0, @event?y > 0).

@see chain->sort

binary_condition<->left: expression Both operants of the condition.
binary_condition<->right: expression Inherits description from: binary_condition-left

binary_condition->initialise: left=expression, right=expression Create the condition from two expressions. There is no use in creating instances of this class as there is no execution defined for it.