Function cells

[Guy Steele <gls@THINK-AQUINAS.ARPA>]

My memory is that a question arose as to whether, given that function
cells and value cells were to be distinct, they should have identical
binding mechanisms or not.  There was no compelling reason to allow
special binding of function names, and the following argument was
advanced against such special bindings: multiprocessing implementations
of Lisp might well prefer to use deep special binding, and it was
undesirable to have to deal with the deep binding mechanism for function
lookups, given that most function-name references, unlike most
variable-name references, occur free.  I recall that this was the
deciding argument that eliminated special binding of function names from
Common Lisp, thereby making function names and variable names dissimilar
in their semantics and further discouraging their merging.

I can report that much of the time I am very happy to have the two names
spaces be distinct.  I get very unhappy whenever I find myself inventing
functionals (functions that take other functions as arguments or return
other functions as values) for various purposes.  For example, I have
found it semantically convenient to do so in Connection Machine Lisp.
In these situations I find the need for interpolated occurrences of
"funcall" and "#'" extremely annoying.
--Guy