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(ql:quickload :trivial-gray-streams)


Gray streams is an interface proposed for inclusion with ANSI CL by David N. Gray in Issue STREAM-DEFINITION-BY-USER ( The proposal did not make it into ANSI CL, but most popular CL implementations implement this facility anyway.

This system provides an extremely thin compatibility layer for gray streams.

How to use it

Use the package TRIVIAL-GRAY-STREAMS to refer Gray stream classes to inherit from, generic functions to implement.


The Gray proposal was made before the ANCI CL standard was finalized, and was based on the Common Lisp The Language book.

The book does not have cl:file-position, cl:read-sequence, cl:write-sequence functions. That's why (we think) the Gray proposal does not specify their counterparts: stream-file-position, stream-read-sequence, stream-write-sequence.

trivial-gray-streams supports these functions:

Generic function STREAM-READ-SEQUENCE (stream sequence start end &key) Generic function STREAM-WRITE-SEQUENCE (stream sequence start end &key)

Notice that we use two required arguments and allow additional
keyword arguments. Your methods on these function should have
compliant lambda lists:
    (stream sequence start end &key)

Generic function STREAM-FILE-POSITION (stream) ⇒ file position Generic function (SETF STREAM-FILE-POSITION) (position-spec stream) ⇒ successp