data structures <--> functions

[cph@KLEPH.AI.MIT.EDU (Chris Hanson)]

   Date: Tue,  8 Dec 87 19:23:30 EST
   From: Jonathan A Rees <JAR@AI.AI.MIT.EDU>

       Date: Sun, 6 Dec 87 01:51:10 est
       From: gjs at ZOHAR.AI.MIT.EDU (Gerald Jay Sussman)
       To:   JAR at AI.AI.MIT.EDU
       Re:   data structures <--> functions

       I really feel the need for EVAL (or ENCLOSE) quite seriously.

As I recall, the original problem with EVAL was just the decision
about whether or not there would be a second argument.  We were unable
to come to concensus because there was no compatible way to solve the
problem without using optional arguments, which no one wanted to do.

Since everyone has EVAL, it seems silly to be tied up on this one
point.  Maybe we should adopt a different procedure, perhaps called
STANDARD-EVAL or GLOBAL-EVAL, which took just one argument.  This
would be identical to EVAL on systems without first-class
environments, and would supply a default environment on the others.