Logic Programming Flashcards
What is the foundation of logic programming?
What is the most widely used logic programming?
Prolog
How can a programmer compute in Prolog?
Give an example of Prolog syntax.
How are databases constructed in Prolog?
Prolog Notes:
Example: Constant Query
Example: Variable Query
Example: Multiple Predicates Query
Example : Assigning one predicate in terms of another predicate
Example: Notations
Example: Sibling Query
How does the interpreter work when searching data?
It is also possible in theory to work forward from the facts trying to see if any of the things you can prove from them are what you were looking for - that can be very time-consuming.
Fancier logic languages use both kinds of chaining, with heuristics or hints from the user to bound the searches.
Example: Resolution Principle
Prolog Unification Rules
List Notation
head(cons(H,T),H) :- isList(T).
tail(cons(H,T),T) :- isList(T).
?- head(cons(2,cons(3,nil)),X).
X = 2
?- head(cons(X,cons(3,nil)),2).
X = 2
Remark: Prolog does not have notion of “input” and “output” variables
Syntactic Sugar For Lists
Example: Stack
Example: Termination
Example: Arithmetic
Example 1: Cut Operator
- Always succeeds as a goal
- “freezes” choice made when encountered
- If cut reached when backtracking, the search of subtrees of the parent node of the cut stops, and the search continues with the grandparent node.
- Cut “prunes” the search tree of all other siblings to the right of the node containing the cut.
Example 2: Cut Operator
Example: Database Manipulation
Example: Non-Monotonic Reasoning
