Issue: SYMBOL-MACROLET-DECLARE (version 1)

[David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>]

Issue:         SYMBOL-MACROLET-DECLARE

References:    SYMBOL-MACROLET (88-002R page 2-81)
               WITH-ACCESSORS (88-002R page 2-88)
               WITH-SLOTS (88-002R page 2-92)

Category:      ADDITION

Edit history:  Version 1, 12-Sep-88, Moon

Problem description:

It would be both natural and nice to be able to write

  (with-slots (rho theta) point
    (declare (single-float rho theta))
    ...computation...)

Proposal (SYMBOL-MACROLET-DECLARE:ALLOW):
	  
Allow declarations at the head of the body of SYMBOL-MACROLET, and hence
in WITH-ACCESSORS and WITH-SLOTS.  Exactly the same declarations are
allowed as for LET, with one exception: SYMBOL-MACROLET signals an error
if a SPECIAL declaration names one of the symbols being defined as a
symbol-macrolet.  A type declaration of one of these symbols is equivalent
to wrapping a THE expression around the expansion of that symbol.

Test Cases/Examples:

See problem description.

Rationale:

If SYMBOL-MACROLET is intended to resemble LET in syntax, it ought to
allow declarations.  When writing a SYMBOL-MACROLET directly, the user
could just as easily write a THE expression instead of a type
declaration.  However, when invoking a macro such as WITH-SLOTS that
expands into SYMBOL-MACROLET, the user does not have this option since
the expansion is not supplied explicitly by the user.

Current practice:

SYMBOL-MACROLET was only tentatively added to Common Lisp 3 months ago.

Cost to Implementors:

Less than one man-hour.

Cost to Users:

None.

Cost of non-adoption:

Minor wart in the language.

Benefits:

More consistent language definition.

Esthetics:

More consistent language definition.

Discussion:

None.