[not loaded]rdf_edit.pl -- RDF edit layer

This library provides a number of functions on top of the rdf_db module:

Broadcast modifications
Provide undo/redo

See also: - rdf_persistency.pl provides reliable persistency, but without changes boardcasting and undo/redo.
To be done: - This library must be rewritten using rdf_monitor/3. This allows using edit layer without having to choose between rdf_ and rdfe_ predicates.

rdfe_update(+Subject, +Predicate, +Object, +Action)

Update an existing triple. Possible actions are:

! subject(+Subject) ! predicate(+Predicate) ! object(+Object) ! source(+Source)

rdfe_delete(+Subject)

Delete a subject and all we know about it. This is a bit tricky. If we are involved in transitive relations, should we re-joint these in this module?

rdfe_load(+File) is det

rdfe_load(+File, +Options) is det

Load an RDF file and record this action including version information to facilitate reliable reload.

rdfe_snapshot_file(-File)

Enumerate the MD5 snapshot files required to restore the current journal file. Using this call we can write a routine that packages the journal file with all required snapshots to restore the journal on another computer.

rdfe_register_ns(Id, URI)

Encapsulation of rdf_register_ns(Id, URI)

rdfe_transaction(:Goal)

Run Goal, recording all modifications as a single transaction. If Goal raises an exception or fails, all changes are rolled-back.

rdfe_undo

Undo a (toplevel) transaction. More calls do further undo. The `Undone' actions are re-added to the undo log, so the user can redo them. Fails if there are no more undo/redo transactions.

rdfe_redo

Start a redo-session

rdfe_can_redo(-TID) is semidet

rdfe_can_undo(-TID) is semidet

Check if we can undo and if so return the id of the transaction that will be un/re-done. A subsequent call to rdfe_transaction_name can be used to give a hint in the UI.

rdfe_transaction_name(+TID, -Name)

Return name if the transaction is named.

rdfe_set_transaction_name(+Name)

Set name of the current transaction

rdfe_transaction_member(+TID, -Action)

Query actions inside a transaction to allow for quick update of visualisers.

rdfe_set_file_property(+File, +Options)

Set properties on the file. Options is one of

access(ro/rw)
default(all/fallback)

rdfe_get_file_property(+FileOrURL, ?Option)

rdfe_get_file_property(-URL, ?Option)

Fetch file properties set with rdfe_set_file_property/2.

rdfe_is_modified(?Source)

True if facts have been added, deleted or updated that have Source as `payload'.

rdfe_clear_modified(+Graph) is det

Consider the current state of Graph as unmodified.

rdfe_set_watermark(Name)

Create a watermark for undo and replay journal upto this point. The rest of the logic needs to be written later.

rdfe_reset

Clear database, undo, namespaces and journalling info.

rdfe_open_journal(+File, +Mode) is det

Open a journal writing to File in Mode. Mode is one of

read: Open and replay the journal
write: Delete current journal and create a fresh one
append: Read and replay the existing journal and append new modifications to the File.

rdfe_close_journal

Close the journal. Automatically called from at program termination from at_halt/1.

rdfe_current_journal(-Path)

Query the currently open journal

rdfe_replay_journal(+File)

Replay a journal file. For now this is our cheap way to deal with save/load. Future versions may be more clever when dealing with the version information stored in the journal.