stream-cdr

(stream-cdr stream)

Returns the rest of a non-empty stream, forcing its promise; the empty stream signals an error. The rest is computed the first time and remembered, so walking a stream twice evaluates each element once. A Structure and Interpretation of Computer Programs (SICP)/MIT name, not R7RS: no library exports it, so it is visible only to a file with no import and at the REPL.