Node:List Predicates, Next:List Constructors, Previous:List Syntax, Up:Lists
Often it is useful to test whether a given Scheme object is a list or not. List-processing procedures could use this information to test whether their input is valid, or they could do different things depending on the datatype of their arguments.
|list? x||Scheme Procedure|
|scm_list_p (x)||C Function|
null? is often used in list-processing code to
tell whether a given list has run out of elements. That is, a loop
somehow deals with the elements of a list until the list satisfies
null?. Then, the algorithm terminates.
|null? x||Scheme Procedure|
|scm_null_p (x)||C Function|