22.3.12 Notes about FORMAT

Formatted output is performed not only by format, but by certain other functions that accept a format control the way format does. For example, error-signaling functions such as cerror accept format controls.

Note that the meaning of nil and t as destinations to format are different than those of nil and t as stream designators.

The ~^ should appear only at the beginning of a ~< clause, because it aborts the entire clause in which it appears (as well as all following clauses).