Re: Sbcl-help Digest, Vol 209, Issue 12; ftype

On 6/18/24 17:03, [email protected] wrote:
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> Today's Topics:
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>     1. Question of the day N1: DECLAIM and SETF (Marco Antoniotti)
>     2. Question of the day N2: ~\Return (Marco Antoniotti)
>     3. Re: Question of the day N1: DECLAIM and SETF (Richard M Kreuter)
>     4. Re: Question of the day N1: DECLAIM and SETF (Marco Antoniotti)
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why not do this..

(defun this (x &optional y)
   (declare (ignorable y))
   (+ x (or y 0)))

CL-USER> (describe #'this)
#<FUNCTION THIS>
   [compiled function]


Lambda-list: (X &OPTIONAL Y)
Derived type: (FUNCTION (T &OPTIONAL T) (VALUES NUMBER &OPTIONAL))
Source form:
   (LAMBDA (X &OPTIONAL Y) (DECLARE (IGNORABLE Y)) (BLOCK THIS (+ X (OR 
Y 0))))
; No value
CL-USER>


or

(defun this (x &optional (y 0))
   (declare (ignorable y))
   (the fixnum (ldb (byte 48 0) (+ x (or y 0)))))


either or the generic + is used.


I see the need to declare functions; but this seems futile with sbcl; 
best to redefine the function (this) (defun $!this () (this))

if you want to inline code and get the type parser to work as best as 
possible keep the code in order.

it would be nice to

(defun this (x) (push x *lst*))

(defvar *this* nil)

but it is not so easy...