make-two-way-stream

(make-two-way-stream input-stream output-stream)

One stream over an input and an output component: reads come from the input stream, writes reach the output stream.

A two-way stream is a Gray stream, so the whole read and write protocol dispatch on it. read-line and the sequence operators work over its input side, and write-char / write-string / format / the print family reach the output side. The components are recoverable with two-way-stream-input-stream and two-way-stream-output-stream.

Each component must stream in the right direction: an input stream that is not one, or an output stream that is not one, signals a type-error.