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Re: Function cells
- To: Bobrow.PA@PARC-MAXC.ARPA
- Subject: Re: Function cells
- From: Deutsch.PA@PARC-MAXC.ARPA
- Date: Thu ,1 Sep 83 19:19:00 EDT
- Cc: TIM%MIT-OZ@MIT-MC.ARPA, lisp-forum@MIT-MC.ARPA, Julian Padget <PADGET@UTAH-20.ARPA>, Teitelman.PA@PARC-MAXC.ARPA
- In-reply-to: "Bobrow's message of Thu, 1 Sep 83 14:30 PDT"
Danny,
I have to side with the Common Lisp / T people on this one. Just
because most (but not all) function invocations use names that are bound
in a global, flat name space (which all modern Lisp systems are finding
ways to enrich), and most (but not all) variables are bound more locally
(in this lexical scope? in a dynamically enclosing but far-from-apparent
scope? in an enclosing lexical scope?), is not enough of a reason for
introducing a mechanism that adds complexity all over the system.
T takes the viewpoint that all identifiers are on a par. The compiler
is able to take advantage of pragmatic information about things being
constant or not dynamically rebound, regardless of whether they are
functions or variables. I imagine Common Lisp is the same.
Function cells seemed like a good idea at the time, just like
GLOBALVARS. I think they were both pragmatic successes and semantic
mistakes.