Issue: APPLYHOOK-ENVIRONMENT (Version 1)

[masinter.pa@Xerox.COM]

!
Forum:	Cleanup
Issue:         APPLYHOOK-ENVIRONMENT

References:    APPLYHOOK (CLtL p. 323)

Category:      CHANGE

Edit history:  Masinter,  6-Jan-89, Version 1

Problem description:

The function APPLYHOOK is documented to take an optional environment
argument. CLtL says "Furthermore, the env argument is used as the lexical
environment for the operation; env defaults to the null environment." 

However, there is no way that the lexical environment can effect the way in
which APPLYHOOK processes its arguments; it merely calls the specified
function, and function call is not affected by lexical environments. (The
"function" argument to APPLYHOOK is a function object.)

This has been regularly a source of confusion for programmers encountering
APPLYHOOK.

Proposal (APPLYHOOK-ENVIRONMENT:REMOVE-ENV): Remove the optional "ENV"
argument to applyhook. 

Rationale:

Removes a very minor wart.

Current practice:

Most implementations accept an extra argument and then ignore it.

Cost to Implementors:

Remove optional ENV argument from APPLYHOOK and any code that passes one to
APPLYHOOK.

Cost to Users:

Remove any ENV argument passed to APPLYHOOK.

Cost of non-adoption:

Continued confusion.

Performance impact:

None

Benefits:

Removes a wart.

Esthetics:

Minor improvement.

Discussion:

This was discussed  on the Common Lisp mailing list several years ago, but
slipped thru the cracks.