Matching Can Be Strict or Loose

Strict equality:

(setq pattern '(quit this program))

(setq subject '(quit this program))

(equal pattern subject) ; => T

Even equality is relative:

(eq 'a 'a) ; => T strictest

(eq 5 5) ; => NIL or T

(eql 5 5) ; => T

(eql 5 5.0) ; => NIL

(= 5 5.0) ; => T

(equal 5 5.0) ; => NIL

(equalp 5 5.0) ; => T most tolerant