[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Small omission in Chap 2

    Date: 9 Mar 88 12:01 EST (Wednesday)
    From: fritzson@PRC.Unisys.COM (Richard Fritzson)

    The description of the standard-generic-function SLOT-MISSING
    indicates that it is called when an attempt is made to access a
    non-existent slot of an object, if the object's metaclass is
    standard-class. This is a reasonable restriction (although I hate what
    happens when I mistakenly apply an accessor function to NIL).

    However, the description of the function SLOT-VALUE doesn't include
    the restriction to objects whose metaclasses are standard-class. It
    seems to say that slot-missing will always be called (even for objects
    whose metaclass is built-in-class).

    I expect that the former was the intended meaning, but they should
    both say the same thing.

Thanks for catching this and sending us a message.

I believe the reason this bug happened in the document is that we tried
to finesse the issue that slot-value actually called the
generic-function slot-value-using-class.  This means that we tried to
put too much of the description of the effect of calling slot-value in
the actual section on slot-value and got tripped up.

I suppose this will be easier to fix now that we actually have chapter
three and can feel free to reference it from chapter 2.