variables

[Jonathan A Rees <JAR@AI.AI.MIT.EDU>]

    Date: 4 Feb 87 07:09:00 EST
    From: "CUGINI, JOHN" <cugini at icst-ecf>

    Just frinstance, no other language I know of that has
    recursion speaks of "different bindings of the same variable" to
    explain what's going on with the parameter list of a recursively
    invoked function.  The CL terminology conjures up the image of one
    object with a changeable property, rather than of different objects,
    each of which is referred to by the same name at different times.

This usage is consistent with the usage in mathematics, and with Alonzo
Church's terminology in his paper on lambda calculus.  To a
mathematician or logician, a variable is a name like "x".  A variable
"varies" exactly because it DOES have different bindings at different
times, e.g. at different steps of a recursion.  It is computer
scientists who have perverted the sense of the word and use it to mean
what ought to be called a location.