enter_suspension_list(+Position, +Attribute, +Susp)

Position

Integer indicating the position of the suspension list.

Attribute

Compound term, typically a variable's attribute.

Susp

A suspension

Description

This predicate is used to add a suspension to a single suspension list. The suspension list is expected in the Position'th argument of the structure Attribute. This argument can be either an existing suspension list, or a variable. If it is a variable, a new suspension list with Susp will be created.

The functionality is similar to insert_suspension/3, but while enter_suspension_list/3 enters only into a single suspension list, insert_suspension/3 finds all variables in a term and inserts a suspension into the attribute structures of all those variables.

Suspension lists should be regarded an opaque data structure and only be accessed and manipulated by the set of primitives provided for this purpose.

Modes and Determinism

• enter_suspension_list(+, +, +) is det

Exceptions

(4) instantiation fault

Attribute, Susp or Position not instantiated.

(5) type error

Attribute is not a structure, or Susp not a suspension or Position is a non-integer number.

(6) out of range

Attribute's arity is less than Position, or Position is zero or less.

(24) number expected

Position is a non-number.

(271) bad format of the variable attribute

The suspension list in Position of Attribute is neither a list nor a free variable, or it contains an element which is not a suspension.

Examples

[eclipse 1]: Att = att(_, hello), init_suspension_list(1, Att),
         make_suspension(true, 3, S), enter_suspension_list(1, Att, S).

Att = att(['SUSP-_286-susp'], hello)
S = 'SUSP-_286-susp'

Delayed goals:
        true
Yes (0.00s cpu)

See Also