Subject: Re: [CSG111] CSG111 MP4: Are procedure names considered variables?
From: Mitchell Wand (wand@ccs.neu.edu)
Date: Fri Feb 11 2005 - 16:25:32 EST
MW> I don't know what you mean by "work with", but yes, procedure names
MW> are definitely variables-- they are no different from any other
MW> variable.
>> We were puzzled because we weren't if we need to keep
>> track of both the procedure address and the address of
>> the arguments. For example, if we've got
>> even(x)
>> it sounds like we need to compute both the address of
>> even and of x. Is this similar to evaluating a
>> procedure, or should we expect to write a new kind of
>> translator for the left side of a function expression?
In the expression
letrec
even(x) = if zero?(x) then 1 else (odd sub1(x))
odd(x) = if zero?(x) then 0 else (even sub1(x))
in (odd 13)
the even and the x in even(x) are both variable _declarations_, not
uses. So they don't get replaced by anything: they are like the
bound variables in a let.
--Prof. Wand
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