HELP PROPERTY_DEFAULT                             John Williams Jun 1985

    property_default(PROP) -> ITEM;

This procedure returns the default value of a property, that is, the
object returned when a property look-up fails. For example:

    vars prop;
    newproperty([[1 one] [2 two] [3 three]], 12, "many", false) -> prop;

    prop(34) =>
    ** many

    property_default(prop) =>
    ** many

-property_default- can be useful when you want to remove entries from a
property. In general,

    property_default(prop) -> prop(item);

will always remove the entry associated with -item- in the property
-prop-.

Also see:

    HELP *NEWPROPERTY       --- Simple property creation
    HELP *NEWANYPROPERTY    --- More complex property creation
    HELP *PROPERTIES        --- Summary of documentation on properties

    REF *PROPS  --- Full information on properties in POP-11



--- C.all/help/property_default
--- Copyright University of Sussex 1992. All rights reserved. ----------
