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shelf_set(+ShelfHandle, +Index, ?Term)

Store a term in a shelf object

ShelfHandle: A shelf handle or shelf name
Index: An integer
Term: An arbitrary term

Description

This stores an arbitrary term in the Index'th slot of the shelf object denoted by ShelfHandle. All other slots of the shelf remain untouched. The setting will persist until it is replaced with a new setting, or until the shelf is destroyed. In particular, the setting will survive backtracking across the call to shelf_set/3.

The slots are numbered from 1 to the maximum which was determined during shelf creation (but note that ECLiPSe's struct-syntax can be used to give the slots symbolic names, see struct/1).

Calling shelf_set/3 with an Index of 0 can be used to set all slots at once. In this case, Term must be a compound term whose functor corresponds to the one that was given during shelf creation. Every shelf slot is set from the corresponding term argument.

Storing and retrieving terms from a shelf involves copying the term each time, similar to what happens in setval/getval and record/recorded. In particular, if the term contains variables, they lose their identity and are replaced with fresh ones. Also, the different slots of a shelf are separate entities, in particular, they cannot share variables between each other.

Note: If ShelfHandle is not a handle, then it must be an atom or a compound term, and the shelf is identified by this term's toplevel functor together with the context module.

Modes and Determinism

shelf_set(+, +, ?) is det

Modules

This predicate is sensitive to its module context (tool predicate, see @/2).

Exceptions

(4) instantiation fault: ShelfHandle is not instantiated
(5) type error: Index is not instantiated
(5) type error: ShelfHandle is not a shelf
(5) type error: Index is not an integer
(6) out of range: Index is negative or greater than the number of slots on the shelf
(40) stale object handle: ShelfHandle refers to an already destroyed shelf

Examples