Getting Answers - RacerPro Reference Manual Version 1.9.2

get-all-remaining-sets-of-rule-consequences

^Function

Description: Like get-next-n-remaining-sets-of-rule-consequences, Page164with n= nil.

get-all-remaining-tuples

^Function

Description: Like get-next-n-remaining-tuples, Page 164withn=nil.

get-answer

^Function

Description: Gets (resp. forces the computation of) the complete answer set (result) of a query or the set of conclusions of a rule, independently if the query resp. rule had been in tuple- or set-at-a-time mode. The query or rule must be active (see query-active-p, Page 128, rule-active-p, Page 134,active-queries, Page 127, active-rules, Page 133) or already pro-cessed (see query-processed-p, Page 128, rule-processed-p, Page 134, processed-queries, Page 127,processed-rules, Page 133)

Syntax: (get-answer id &rest args &key execute-p verbose-p

dont-show-variables dont-show-head-projection-operators-p dont-show-lambdas-p)

Arguments: id - nil.

execute-p, defaultnil- if tis specfied, the query is automatically started (executed);execute-query, Page150will be called. Theargswill be passed through toexecute-query, Page 150.

verbose-p, defaultt- if t is specfied, also head projection operators are shown literally in the result tuples.

dont-show-variables, defaultnil - a list of variables. Usually, a variable binding is shown as a (variable value) entry in a result tuple. If the variable is a member in the list dont-show-variables, then only value will be included in the result tuples.

dont-show-head-projection-operators-p, defaultnil- the results of projection operators are usually included in the form (operator operator-result) in the result tuples. Specify t if only the opera-tor result shall appear in the result tuples.

dont-show-lambdas-p, defaultnil - same as dont-show-head-projection-operators-p, but for solely for lambda operators.

args - seeexecute-query, Page 150.

Values: A list of tuples, or t or nil, or a list of lists of ABox assertions (the rule consequences), or :NOT-FOUND.

Remarks: Can be called an arbitrary number of times on a query or rule. The an-swer is stored in the query resp. rule object and is thus not recomputed if get-answer is called. You can check with query-accurate-p, Page 142 (resp. rule-accurate-p, Page143) whether the stored answer is still valid.

See also the value of describe-query, Page119. In case of a rule, the rule consequences can be added withadd-chosen-sets-of-rule-consequences, Page 172.

Note that the query or rule named id must be on the list of active or pro-cessed queries (see active-queries, Page 127, processed-queries, Page 127), otherwise:NOT-FOUNDis returned.

The tuples are actually computed by repeated calls toget-next-tuple, Page 166. Thus, also special tokens (markers) returned byget-next-tuple, Page 166might appear in the answer.

See also: get-next-tuple, Page 166, get-next-n-remaining-tuples, Page 164, add-chosen-sets-of-rule-consequences, Page 172, active-queries, Page 127,processed-queries, Page127

get-answer-size

^Function

Description: Like get-answer, Page 163, but only returns the number of result tuples (resp. number of sets of rule conclusions).

get-current-set-of-rule-consequences

^Function

Description: Returns the result of the last call toget-next-set-of-rule-consequences, Page 165on the rule id.

get-current-tuple

^Function

Description: Returns the result of the last call toget-next-tuple, Page166on the query id

Syntax: (get-current-tuple id)

Arguments: id - the ID of the query, or:last, or:last-query.

Values: See get-next-tuple, Page 166. Moreover, nil is returned if there was no previous call toget-next-tuple.

get-next-n-remaining-sets-of-rule-consequences

^Function

Description: Like get-next-set-of-rule-consequences, Page 165, but now the nextn remaining sets are requested. Pass nil if you want all remaining sets; see also get-all-remaining-sets-of-rule-consequences, Page 161.

get-next-n-remaining-tuples

^Function

Description: Like get-next-tuple, Page 166, but now the next n remaining tu-ples are requested. Pass nil if you want all remaining tuples; see also get-all-remaining-tuples, Page 161.

get-next-set-of-rule-consequences

^Function

Description: Gets the next set of rule consequences of the rule id. The rule must be on the list of active-rules, Page 133 orprocessed-rules, Page 133. A rule can also be started (executed); useexecute-p argument

Syntax: (get-next-tuple id &rest args)

Arguments: id - the ID of the rule, or:last, or:last-rule.

execute-p, defaultnil- specify t if the rule is ready to also fire it. The query will be started / executed then. The args are passed to execute-query, Page 150(however, the query is always executed in tuple-at-a-time mode, this cannot be overridden).

args - seeexecute-query, Page 150.

Values: The tuple, or:exhaustedin case there are no more tuples, or special tokens such as:not-found,:inconsistent, etc.

Remarks: If the query had been started in lazy tuple-at-a-time mode, then computation of the next tuple might eventually take some time and thus the function might not return immediately.

However, if the query had been started in eager mode, then there is a chance that the next tuple (and probably some more tuples not yet requested) have already been pre-computed, and are thus already available. The function next-tuple-available-p, Page166can be used to check for the availability of such (immediately available) tuples.

Note that a query might still have tuples available, even if the query process (thread) has already terminated and thus the query is no longer active (the query already appears on the list of processed-queries, Page 127). This happens in the eager tuple-at-a-time mode.

See also: next-tuple-available-p, Page 166, get-current-tuple, Page 163, get-next-n-remaining-tuples, Page 164

get-next-tuple

^Function

Description: Gets the next tuple from query id. The query must be on the list of active-queries, Page127orprocessed-queries, Page127. A ready (pre-pared) query can also be started (executed), see execute-p argument. For rules, get-next-set-of-rule-consequences, Page165must be used Syntax: (get-next-tuple id &rest args)

Arguments: id - the ID of the query, or:last, or:last-query.

execute-p, defaultnil- specify t to start (execute) a prepared (ready) query. Theargsare passed toexecute-query, Page150(however, the query is always executed in tuple-at-a-time mode, this cannot be overridden).

args - seeexecute-query, Page 150.

Values: The tuple, or :exhaustedin case there are no more tuples, or special tokens such as:not-found,:inconsistent, etc.

Remarks: If the query had been started in lazy tuple-at-a-time mode, then computation of the next tuple might eventually take some time and thus the function might not return immediately.

See also: next-tuple-available-p, Page 166, get-current-tuple, Page 163, get-next-n-remaining-tuples, Page 164

next-set-of-rule-consequences-available-p

^Function

Description: Checks for the availability of the next set of rule consequences This is the rule equivalent ofnext-tuple-available-p, Page 166.

Syntax: (next-set-of-rule-consequences-available-p id) Arguments: id - the ID of the rule, or:last, or:last-rule.

Values: tornil (or:not-found).

Remarks: If this function returnst, thenget-next-set-of-rule-consequences, Page 165returns that set immediately (without computation delay; the API does not block).

See also: Rule equivalent of next-tuple-available-p, Page 166.

get-next-set-of-rule-consequences, Page165

next-tuple-available-p

^Function

Description: Checks for the availability of the next answer tuple from a query Syntax: (next-tuple-available-p id)

Arguments: id - the ID of the query, or:last, or:last-query.

Values: tornil (or:not-found).

Remarks: If this function returnst, thenget-next-tuple, Page166returns that tuple immediately (without computation delay; the API does not block).