Programming with Logic

一、Introduction

1，"Programming with Logic" Different from other programming languages – Declarative (not procedural) – Recursion (no “for” or “while” loops) – Relations (no functions) – Unification 2，History First 1972.

二、Basic

1、Structure

The end of a clause is marked with a full stop.

There are five clauses in this knowledge base: two facts, and three rules. There are three predicates in this knowledge base: happy, listens2music, and playsAirGuitar 案例 facts, rules and queries built out of Prolog terms

2，Prolog Terms

(1)Simple Terms

注：常量以小写开头，变量以大小或者_开头

(2)Complex terms

Atoms, numbers and variables are building blocks for complex terms Complex terms are built out of a functor directly followed by a sequence of arguments – Arguments are put in (), separated , – The functor must be an atom Examples – playsAirGuitar(jody) – loves(vincent, mia) –hide(X,father(father(father(butch))))

--Arity

The number of arguments a complex term has is called its arity

woman(mia) is a term with arity 1 loves(vincent,mia) has arity 2

You can define two predicates with the same functor but with different arity In Prolog documentation, arity of a predicate is usually indicated with the suffix "/" followed by a number to indicate the arity

happy(yolanda). listens2music(mia). listens2music(yolanda):- happy(yolanda). playsAirGuitar(mia):- listens2music(mia). playsAirGuitar(yolanda):- listens2music(yolanda).
– happy/1 – listens2music/1 – playsAirGuitar/1

三、logic

1，逻辑符号

	Prolog	Logic
Implication	A:-B	B->A
Conjunction	A,B	A∧B
Disjunction	A;B	A ∨ B
Negation	\
案例