equal

Type:	-	predicate function (subr)
Source:	-	xllist.c, xlsubr.c

Syntax

Description

Two expressions are 'equal':

• If the expressions are eql.

• If two strings are string=.

• If the two cars in conses are 'equal' and the two cdrs in conses are 'equal'.

In all other cases 'equal' returns NIL. Note that arrays are only 'equal' if they are eq.

A way to view 'equal' is that if 'expr1' and 'expr2' were printed [via print or princ] and they look the same, then 'equal' will return  T .

Examples

(equal 'a 'a)          => T
(equal 1 1)            => T
(equal 1 1.0)          => NIL  ; different number types
(equal 1.0 1.0)        => T
(equal "a" "a")        => T
(equal '(a b) '(a b))  => T
(equal 'a 34)          => NIL

(setq a '(a b))        ; set value of A to (A B)
(setq b a)             ; set B to point to A's value
(setq c '(a b))        ; set value of C to different (A B)
(equal a b)            => T
(equal a c)            => T

(equal '(a b) '(A B))  => T
(equal '(a b) '(c d))  => NIL

(equal "a" "A")        => NIL
(equal "abc" "abcD")   => NIL

See also eq, eql, cl:equalp.

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