set_expression

Description:

public void set_expression (Expression? expression)

Sets the expression that is evaluated to obtain numbers from items.

Unless an expression is set on this, the sorter will always compare items as invalid.

The expression must have a return type that can be compared numerically, such as g_type_int or g_type_double.

this	a `GtkNumericSorter`
expression	a `GtkExpression`