with-output-to-string

[David A. Moon <Moon@SCRC-STONY-BROOK.ARPA>]

    Date: Wednesday, April 23, 1986  07:12:11
    From: Alan Snyder <snyder%hplsny@hplabs.ARPA>

    I haven't looked too hard, so perhaps I am missing something, but: What
    function is used by WITH-OUTPUT-TO-STRING to create an output stream to an
    existing string?  

One that isn't documented.

    MAKE-STRING-OUTPUT-STREAM does not take an argument.

In some implementations WITH-OUTPUT-TO-STRING does not work by calling
MAKE-STRING-OUTPUT-STREAM, since the former stream has dynamic extent
and the latter stream has indefinite extent.

The extension I think you are proposing is reasonable as an extension.
Do you propose that GET-OUTPUT-STREAM-STRING be allowed on that type
of stream?