Get-Setf-Method

[Glenn S. Burke <GSB@MIT-MC.ARPA>]

    Date: Sun, 2 Jun 1985  15:20 EDT
    From: "Scott E. Fahlman" <Fahlman@CMU-CS-C.ARPA>

    Steve Handerson has pointed out that MACRO-FUNCTION also needs an
    optional evironment argument, since without this we have no way of
    getting hold of the expansion function for a lexically defined macro
    (though we can execute this function).  This may or may not be important
    for normal code, but it is definitely important for writing environment
    tools such as a single-stepper.

    -- Scott

Yes. I don't remember why, but apparently it was important to something in
NIL. I don't think it was  just the stepper.  From the looks of the
sources we put this in last october or earlier.