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minimalkb API

Core API

Statements

minimalkb currently only support binary predicates, using the infix syntax to represent symbolic statements: subject predicate object. For instance: sky0 hasColor blue

Statements are represented as a single string, with the subject, predicate and object separated by a space character.

Subjects and predicates must by valid OWL identifiers. Objects can be either OWL identifiers, or literals. String literals must be surrounded by double quotes.

OWL identifiers might include XML namespaces, separated with a semi colon. For instance: james rdf:type oro:Human.

A partial statement is a statement with a least one unbound member. Unbound variable must start with a question mark ?. For instance: ["?ag sees obj1", "?ag rdf:type Human"]. Partial statements are masks or patterns, and used as such in methods like find.

Models

Several methods take an optional models parameter. If set to None or to an empty list, the method will update/query statements in the robot's base cognitive model. If set to a list containing a single string all, all the existing models are update/queried. Otherwise, you can pass a list of modelsyou want to update/query.

Methods

  • about(resource, models=None)

  • add(stmts, models=None, lifespan=0): adds statements to the given model(s) with the given lifespan. Alias for revise with policy['method']='add'.

  • check(stmts, models=None):

  • classesof(concept, direct=False, models=None)

  • clear()

  • details(resource, models=None): returns a dictionary containing the following details on a given resource:

    • name: resource label, if any, literal value for literals, else resource ID.
    • id: resource ID or literal for literals
    • type: one of ['instance', 'class', 'object_property', 'datatype_property', 'undecided']
    • sameAs: list of equivalent classes or instances, if any
    • 'attributes':
      • for classes, a list of three dictionaries: {"name": "Parents","id": "superClasses", "values":[ids...]} {"name": "Children","id": "subClasses", "values":[ids...]} {"name": "Instances","id": "instances", "values":[ids...]} (only direct super/sub-classes and instances)
      • for instances, a list of one dictionary: {"name": "Classes","id": "classes", "values":[ids...]} (only direct classes)

  • exist(stmts, models=None)

  • find(vars, patterns, constraints=None, models=None): depending on the arguments, three differents behaviours are possible:

    • if len(vars) == 1, find returns a set of resources matching the patterns.
    • if len(vars) > 1:
      • if len(patterns) == 1, a list of statements matching the pattern is returned.
      • else, a list of dictionaries is returned with possible combination of values for the different variables. For instance, find(["?agent", "?action"], ["?agent desires ?action", "?action rdf:type Jump"]) would return something like: [{"agent":"james", "action": "jumpHigh"}, {"agent": "laurel", "action":"jumpHigher"}]

    Note that constraints is currently not supported.

  • findmpe(vars, pattern, constraints=None, models=None): finds the most probable explanation. Currently strictly equivalent to find, as minimalkb does not currently support probabilistic reasoning.

  • hello(): returns the version number of the minimalkb server as a string. Can be used to check connection status.

  • load(filename, models=None): loads the content of the specified OWL ontology. Note that this capability is only available if RDFlib is available to the server.

  • lookup(resource, models=None)

  • methods(): list available methods

  • retract(stmts, models=None): alias for revise with policy['method']='retract'.

  • revise(stmts, policy): Add/retract/updates one or several statements in the specified model.

    policy is a dictionary with the following fields:

    • method (required): string in [add, safe_add, retract, update, safe_update, revision]
    • models (optional, default to None): list of strings
    • lifespan (optional, default to 0): duration before automatic removal of statements, in seconds, float. If set to 0, statements do not expire.

  • subscribe(type, trigger, var, patterns, models=None)

  • update(stmts, models=None, lifespan=0): updates statements in the given model(s) with the given lifespan. Alias for revise with policy['method']='update'. If the predicate(s) are not inferred to be functional (i.e., it accept only one single value), behaves like add.

Backward compatibility with ORO

Do not use these function calls in new code. They might be removed in the future.

  • findForAgent(agent, var, stmts) (compatibility)
  • `getClassesOf(concept, direct=False) (compatibility)``
  • getDirectClassesOf(concept) (compatibility)
  • getLabel(concept) (compatibility)
  • getResourceDetails(concept) (compatibility)
  • listAgents() (compatibility)
  • listSimpleMethods() (compatibility)
  • lookupForAgent(agent, resource) (compatibility)
  • registerEvent(type, trigger, patterns) (compatibility)
  • remove(stmts, models=None) (compatibility)
  • removeForAgent(agent, stmts) (compatibility)
  • reset() (compatibility)
  • safeAdd(stmts, lifespan=0) (compatibility)
  • stats() (compatibility)