chain=?

[procedure] chain=? compare x1 ...

[procedure] chain<? compare x1 ...

[procedure] chain>? compare x1 ...

[procedure] chain<=? compare x1 ...

[procedure] chain>=? compare x1 ...

SRFI-67: Test if the values x1 ...(zero or more values) form a chain with respect to the relation specified by the name of the procedure, and with respect to the compare procedure compare. The result is a boolean (either #t or #f.) The order in which the values are compared is unspecified, but each value is compared at least once (even if there is just one.)

A sequence of values x1, ..., x[n] forms a chain with respect to the relation rel? if (rel? compare x[i] x[j]) for all 1 < i < j < n.