Simple streams are an extensible streams protocol that avoids some problems with Gray streams.
Documentation about simple streams is available at:
The implementation should be considered Alpha-quality; the basic framework is there, but many classes are just stubs at the moment.
See SYS:CONTRIB;SB-SIMPLE-STREAMS;SIMPLE-STREAM-TEST.LISP for things that should work.
Known differences to the ACL behaviour:
opennot return a simple-stream by default. This can be adjusted; see default-open-class in the file cl.lisp