eql(a, b) {(a, a) 
bool :: (a in any)}
Given two objects of the same type, eql will return t if
they are equal and f otherwise. Two sequences are equal if they
are the same length and their elements are elementwise equal. Two
records are equal if their fields are equal.
hash(a, l) {(a, int) 
int :: (a in any)}
Hashes the argument a and returns an integer in the range
[0..l). This will always generate the same result for equal
values as long as it is run on the same machine. In particular
floating-point hashing can depend on the floating-point
representation, which is machine dependent. There is no guarantee
about the distribution of the results--returning 0 for all keys
would be a valid implementation, although we expect an implementation
to do much better than that.
select(flag, v1, v2) {(bool, a, a) 
a :: (a in any)}
Returns the second argument if the flag is T and the third
argument if the flag is F. This differs from an if
form in that both arguments are evaluated.
identity(a) {a 
a :: (a in any)}
Returns the identity for any type. The identity of a sequence is
an empty sequence of the same type. The identity of a number is 0,
the identity of a boolean is f (false), and the identity of a
character is the null character. The identity of a pair is a pair
of the identities of the two elements.