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


    Date: Thu, 20 Nov 1986  16:19 EST
    From: "Scott E. Fahlman" <Fahlman@C.CS.CMU.EDU>
    EVAL cannot easily be defined to work in the lexical environment in
    which it appears because that lexical environment is not around at
    runtime, when the argument to EVAL arrives and the evaluation occurs.
    In any event, it would eliminate many of the benefits of lexical
    scoping to provide a loophole through which arbitrary forms might be
    smuggled into a lexical environment at runtime.  For example, certain
    optimization are now possible because the compiler can examine all
    possible references to a lexically-bound variable by scanning the
    lexical block in which it is bound; thsi would go away in the presence
    of your LEXICAL-EVAL....

Right.  This demonstrates that LEXICAL-EVAL would have to be a new special
form, rather than simply a function.