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Date: Mon, 21 Jul 1986 21:46 EDT
From: "Scott E. Fahlman" <Fahlman@C.CS.CMU.EDU>
Proposal #5: PARSE-BODY
Add a new function (PARSE-BODY body environment documentation-allowed-p).
It pulls apart the body into three parts: a list of DECLARE forms, a
documentation string (or NIL if none), and the body proper. These are
returned in the order body, declarations, and doc-string as three
values. PARSE-BODY may perform macro-expansion (using the given
environment) in order to determine whether an initial macro-call expands
into a DECLARE form or documentation string.
There could be an &optional before then environment and doc-p args
(environment args are optional everywhere else: ie macroexpand and (proposed) eval.)
I have found it more convenient to return a list of declarations
(ie the "insides" of declare forms) rather than declare forms themselves.
That is, I would have
(parse-body '((declare (type atom x) (weird y)) (declare (special z y))))
return a decls value of ((atom x) (weird y) (special z y)).
This makes it easier for the caller to do assoc tests for certain kinds
of relevant declarations.
A sample call to this style of parse-body looks like:
(multiple-value-bind (body decls)
(parse-body body environment)
(return-from ,block-name (progn . ,body))))
What ever happened to the (declare (documentation "foo")) proposal?
(The documentation declaration being equivalent to supplying a doc-string)
KMP (I believe) suggested this a long time ago and a lot of people seemed
to think that it was a good and necessary thing (some going as far as to
If there were such a documentation declaration, a doc-string could just
be returned from PARSE-BODY as part of the declarations rather than as a
separate value. (The doc-string-valid-p arg is still needed, though)