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Issue MACROEXPAND-HOOK-INITIAL-VALUE Writeup

Forum:		Public Review

Issue: MACROEXPAND-HOOK-INITIAL-VALUE

References: Moon's public review comment #15

*MACROEXPAND-HOOK* (p. 3-78)

Category: CHANGE

Edit history: 21 Dec 1992, Version 1 by Loosemore

Status: Proposal IMPLEMENTATION-DEPENDENT passed 9-0-0, Mar 1993

Problem description:

Page 3-78 says the initial value of *macroexpand-hook* is "a

designator for the function funcall". I think the initial value should

be implementation dependent, because some implementations use

*macroexpand-hook* to provide information to their program development

environment on which macros are in use.

Proposal (MACROEXPAND-HOOK-INITIAL-VALUE:IMPLEMENTATION-DEPENDENT):

(1) Change the description of the initial value of *MACROEXPAND-HOOK*

to say that it is a designator for a function that is equivalent to

the function FUNCALL, but which can have additional

implementation-dependent side-effects.

(2) Add to the notes section of the dictionary entry for

*MACROEXPAND-HOOK* a statement that users who put their own function

into *MACROEXPAND-HOOK* should consider saving the previous hook and

calling it from their function.

Rationale:

Adopting this proposal would make *MACROEXPAND-HOOK* more useful.

Current practice:

Unknown.

Cost to implementors:

None.

Cost to users:

Probably little or none.

Aesthetics:

Neutral.

Editorial impact:

The change is confined to the dictionary entry for *MACROEXPAND-HOOK*.

Discussion:


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