23.4 Predicates

Function: not-pair? obj

Defined as:

(lambda (x) (not (pair? x)))

provided as a procedure as it can be useful as the termination condition for list–processing procedures that wish to handle all finite lists, both proper and dotted.

Function: circular-list? obj

Function: circular-list?/or-null obj

Return #t if obj is a circular list. The ‘/or-null’ variant returns #t also if obj is null.

Function: dotted-list? obj

Function: dotted-list?/or-null obj

Return #t if obj is a dotted list. The ‘/or-null’ variant returns #t also if obj is null.

Function: and-null? ell ...

Syntax: and-null?/stx ell ...

Return #t if all the ell are null or no arguments are given.

Function: or-null? ell ...

Syntax: or-null?/stx ell ...

Return #t if at least one of the ell is null. Return #f if no arguments are given.

Function: and/or-null? ell ...

Syntax: and/or-null?/stx ell ...

Return two values being the return values of and-null? and or-null? applied to the ell arguments.