(assoc U:any V:a-list): pair, nil expr
If U occurs as the car portion of an element of the a-list V, the pair in which
U occurred is returned, otherwise nil is returned. The function equal is used
to test for equality. As illustrated below, it is possible to update the table
that was the second argument to assoc by using the function rplacd on the
result.
(atsoc R1:any R2:any): any expr
Similar to assoc except that eq is used to make comparisons.
(ass F:function U:any V:a-list): pair, nil expr
Ass is a generalized assoc function. F is the comparison function.
(sassoc U:any V:a-list FN:function): any expr
Searches the a-list V for an occurrence of U. If U is not in the a-list, the
evaluation of function FN is returned. Note that FN should be a function
with no formal parameters.
(pair U:list V:list): a-list expr
U and V are lists which must have an identical number of elements. If not,
an error occurs. Returned is a list in which each element is a pair, the car of
the pair being from U and the cdr being the corresponding element from V.