assoc find the entry in an alist
for a given key, and return the
assoc-ref do a similar
lookup, but return just the value.
Return the first entry in alist with the given key. The return is the pair
(KEY . VALUE)from alist. If there's no matching entry the return is
assqcompares keys with
equal?. See also SRFI-1 which has an extended
assoc(SRFI-1 Association Lists).
Return the value from the first entry in alist with the given key, or
#fif there's no such entry.
assq-refcompares keys with
Notice these functions have the key argument last, like other
-reffunctions, but this is opposite to what what
assqetc above use.
When the return is
#fit can be either key not found, or an entry which happens to have value
assqetc above if you need to differentiate these cases.