Name/Value pair used to pass named arguments to methods. A binding is
written as Name := Value and is recognised by send_method->send
when it scans an argument list, allowing the caller to skip optional
arguments by name. See send_method->send
for the full argument binding rules.
The following example creates a menu_item named help
whose
end_group slot is set via a binding rather than by
positional arguments:
?- new(X, menu_item(help, end_group := @on)).
|function|function:=
syntactic shorthand rather than constructed explicitly.