FactBase type (joe)

A FactBase is an in-memory database of Nero Fact values. The database can be updated and queried using Nero FactBase values.

Static Methods

Initializer

Methods

Input/Output

Subject to particular constraints, the contents of a FactBase can be output as a Nero script via the FactBase.asNero() and toNero() methods, and later read back in via the FactBase.fromNero() method.

The constraints are (currently) as follows:

  • All facts must be ordered
  • All field values must be scalar values representable as Joe literals.

Static Methods

FactBase.asNero()

FactBase.asNero(facts) → String

Given a set of facts, outputs the facts as a script of Nero axioms subject to certain constraints.

The facts value can be a FactBase or a collection of values to be converted to facts. Throws an Error if any value cannot be used as a Fact.

FactBase.fromNero()

FactBase.fromNero(script) → FactBase

Given a Nero script, executes the script and returns a FactBase containing all known facts.

FactBase Initializer

FactBase([facts]) → FactBase

Creates an FactBase, optionally populating it with the given facts. The facts value can be a FactBase or a collection of values to be converted to facts. Throws an Error if any value cannot be used as a Fact.

Methods

factBase.add()

factBase.add(fact) → this

Adds a single value to the database as a Fact. Throws an Error if the value cannot be used as a Fact.

factBase.addAll()

factBase.addAll(facts) → this

Adds a collection of values to the database as Fact values. The facts value can be a FactBase or a collection of values to be converted to facts. Throws an Error if any value cannot be used as a Fact.

Note: adding the contents of another FactBase is much faster than adding an arbitrary collection.

factBase.all()

factBase.all() → Set

Returns a read-only Set of all facts in the database.

factBase.clear()

factBase.clear() → this

Clears the database of all content.

factBase.filter()

factBase.filter(predicate) → Set

Returns a set containing the elements for which the filter predicate is true.

factBase.isDebug()

factBase.isDebug() → Boolean

Returns the database's debug flag.

factBase.isEmpty()

factBase.isEmpty() → Boolean

Returns true if the database is empty, and false otherwise.

factBase.map()

factBase.map(func) → Set

Returns a set containing the items that result from applying function func to each item in this set.

factBase.relation()

factBase.relation(relation) → Set

Returns a read-only Set of all facts in the database that have the given relation.

factBase.relations()

factBase.relations() → Set

Returns a read-only Set of the names of the relations of the facts in the database.

factBase.remove()

factBase.remove(fact) → this

Deletes a single Fact from the database.

factBase.removeAll()

factBase.removeAll(facts) → this

Deletes a collection of facts from the database. The facts value can be a FactBase or a collection of values to be converted to facts.

factBase.removeIf()

factBase.removeIf(predicate) → this

Deletes facts matching the predicate from the database.

factBase.removeRelation()

factBase.removeRelation(name) → this

Deletes an entire relation from the database.

factBase.renameRelation()

factBase.renameRelation(oldName, newName) → this

Renames a relation, replacing any existing relation that has the new name.

factBase.select()

factBase.select(rules) → Set

Queries the database using the Nero rules and returns all inferred facts. If the rule set contains export directives then the relevant facts will be exported as domain values. The database itself is not modified.

factBase.setDebug()

factBase.setDebug(flag) → this

Sets the database's debug flag. If enabled, update() and select() will output a detailed Nero execution trace.

factBase.size()

factBase.size() → Number

Returns the number of facts in the database.

factBase.toNero()

factBase.toNero() → String

Returns a Nero script containing the database items as Nero axioms.

factBase.toString()

factBase.toString() → String

Returns the value's string representation.

factBase.update()

factBase.update(rules) → this

Updates the database using the Nero rules. Inferred facts are added to the database and then returned to the caller. It is an error if the rule set contains export directives.