In computer science, pattern-directed invocation programming languages are programming languages in which procedures are invoked indirectly by specifying a pattern for a set of procedures as opposed to specifying one directly by name, pointer, URL, etc., as in conventional programming. These languages were initiated by Planner which featured high level plans invoked by patterns for assertions and goals. They include logic programming languages such as Prolog as a special case. Ether was a pattern-directed invocation language introduced in the Scientific Community Metaphor.
Pattern-directed invocation is a commonly used and more practical alternative to first-order theorem proving in automated theorem proving, and is the primary method of implementing a blackboard system for automated reasoning in general. In it, a database of facts (a la Prolog) is augmented with a set of procedures called demons. A demon is automatically invoked whenever a term matching the demon's pattern is added to the database.
Pattern-directed invocation is related to rule-based programming.
Famous quotes containing the words pattern, directed, programming and/or language:
“With only one life to live we can’t afford to live it only for itself. Somehow we must each for himself, find the way in which we can make our individual lives fit into the pattern of all the lives which surround it. We must establish our own relationships to the whole. And each must do it in his own way, using his own talents, relying on his own integrity and strength, climbing his own road to his own summit.”
—Hortense Odlum (1892–?)
“Religion, or the duty which we owe our Creator, and the manner of discharging it, can be directed only by reason and conviction, not by force and violence; and therefore all men are equally entitled to the free exercise of religion, according to the dictates of conscience.”
—James Madison (1751–1836)
“If there is a price to pay for the privilege of spending the early years of child rearing in the driver’s seat, it is our reluctance, our inability, to tolerate being demoted to the backseat. Spurred by our success in programming our children during the preschool years, we may find it difficult to forgo in later states the level of control that once afforded us so much satisfaction.”
—Melinda M. Marshall (20th century)
“This poem is concerned with language on a very plain level.
Look at it talking to you.”
—John Ashbery (b. 1927)