gtk:numeric-sorter-expression (object)

object -- a gtk:numeric-sorter object
expression -- a gtk:expression instance, or nil

Accessor of the expression slot of the gtk:numeric-sorter class. The gtk:numeric-sorter-expression function gets the expression that is evaluated to obtain numbers from items. The (setf gtk:numeric-sorter-expression) function sets the expression.

Unless an expression is set on object, the sorter will always compare items as invalid. The expression must have a return type that can be compared numerically.