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Recorded Database

The record-family of built-ins to store data across failures   [more]

Predicates

current_record(?Key)
Succeeds if Key is the key of a recorded item.
erase(+DBRef)
Succeeds if the database reference DBRef designates a term recorded in the record database and this term is successfully erased.
erase(+Key, ?Value)
Succeeds if the term Value associated with key Key is removed as an entry from the record database.
erase_all(+Key)
All the the values associated with key Key are removed from the record database.
is_record(+Key)
Succeeds if Key is a key of a recorded item.
local record(+Name)
Create a named record object
record(+Key, ?Value)
Records the term Value after all other entries for key Key in the record database.
record_create(-Handle)
Create an anonymous record handle
record_wait_append(+Key, ?Value, +Timeout, +Max)
Variant of recordz/2, suitable for thread communication
record_wait_remove(+Key, ?Value, +Timeout)
Variant of erase/2, suitable for thread communication
recorda(+Key, ?Value)
Records the term Value before all other entries for key Key in the record database.
recorda(+Key, ?Value, -DBRef)
Records the term Value before all other entries for key Key in the record database.
recorded(+Key, ?Value)
Succeeds if the term Value has been recorded in the record database under the key Key.
recorded(+Key, ?Value, -DBRef)
Succeeds if the term Value has been recorded in the record database under the key Key and DBRef is its unique reference.
recorded_count(+Key, -Count)
Returns the number of entries under the record key
recorded_list(+Key, -List)
Succeeds if the List is the list of all terms that are currently recorded in the record database under the key Key.
recordz(+Key, ?Value)
Records the term Value after all other entries for key Key in the record database.
recordz(+Key, ?Value, -DBRef)
Records the term Value after all other entries for key Key in the record database.
referenced_record(+DBRef, -Value)
Succeeds if Value is the Term recorded under the database reference DBRef.
rerecord(+Key, ?Value)
Erases all entries recorded under key Key and replaces them with the given value Value.

Description

ECLiPSe provides several facilities to store information across backtracking. The following table gives an overview. If at all possible, the handle-based facilities (bags, records, shelves, stores) should be preferred because they lead to cleaner, reentrant code (without global state) and reduce the risk of memory leaks.

    Facility        Type            Reference       See
    ================================================================
    bags            unordered bag   by handle       bag_create/1
    ----------------------------------------------------------------
    anon.records    ordered list    by handle       record_create/1
    ----------------------------------------------------------------
    shelves         array           by handle       shelf_create/2,3
    ----------------------------------------------------------------
    stores          hash table      by handle       store_create/1
    ----------------------------------------------------------------
    named shelves   array           by name         shelf/2
    ----------------------------------------------------------------
    named stores    hash table      by name         store/1
    ----------------------------------------------------------------
    non-logical     single cell     by name         variable/1,2
    variables
    ----------------------------------------------------------------
    non-logical     array           by name         array/1,2
    arrays
    ----------------------------------------------------------------
    named records   ordered list    by name         record/1
    ----------------------------------------------------------------
    dynamic         ordered list    by name         dynamic/1,assert/1
    predicates
    ----------------------------------------------------------------

The record-facilities described in this section provide a non-logical form of storage (not subject to backtracking), organized conceptually as a list. Elements can be added at either ends of the list, while elements can be removed from any position in the list. The basic concept of this facility goes back to C-Prolog. ECLiPSe provides additional functionality in the form of anonymous record handles, and facilities for communicating between concurrent threads.


Generated from record.eci on 2017-09-08 15:30