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at 2023-08-22T14:39:12-07:00

Add macro PROCESS-SET to handle processing of set functions

All of the (non-destructive) set functions have basically the same
processing code.  The only difference is how to initialize the result
and the test used to determine if an item is to be added to the
result.

We encapsulate this similarity in  the macro `PROCESS-SET` and use it
in `union`, `intersection`, and `set-difference`.

@@ -750,6 +750,18 @@
 )
  (declaim (start-block list-to-hashtable union intersection set-difference))
++
 +;; Main code to process a set function.  INIT-RES initializes the
 +;; value of RES, which holds the result of the set function.
 +;; TEST-FORM is a form that tests whether to add the item from LIST1
 +;; to RES.
 +(defmacro process-set (init-res test-form)
 +  `(let ((res ,init-res))
 +     (dolist (item list1)
 +       (when ,test-form
 +         (push item res)))
 +     res))
++
  ;; Convert a list to a hashtable.  The hashtable does not handle
  ;; duplicated values in the list.  Returns the hashtable.
  (defun list-to-hashtable (list key test test-not)
@@ -791,18 +803,10 @@
    (declare (inline member))
    (when (and testp notp)
      (error (intl:gettext "Test and test-not both supplied.")))
 -  (let ((res list2)
 -	(hashtable (list-to-hashtable list2 key test test-not)))
 -    (macrolet
 -        ((process (test-form)
 -         `(dolist (item list1)
 -	    (unless ,test-form
 -	      (push item res)))))
 -      (cond (hashtable
 -             (process (nth-value 1 (gethash (apply-key key item) hashtable))))
 -            (t
 -             (process (with-set-keys (member (apply-key key item) list2)))))
 -      res)))
 +  (let ((hashtable (list-to-hashtable list2 key test test-not)))
 +    (if hashtable
 +        (process-set list2 (not (nth-value 1 (gethash (apply-key key item) hashtable))))
 +        (process-set list2 (not (with-set-keys (member (apply-key key item) list2)))))))
  (defun intersection (list1 list2 &key key
@@ -812,18 +816,10 @@
    (if (and testp notp)
        (error "Test and test-not both supplied."))
    (let ((hashtable
 -	  (list-to-hashtable list2 key test test-not)))
 -    (macrolet
 -        ((process (test-form)
 -           `(let ((res nil))
 -	      (dolist (item list1)
 -	        (if ,test-form
 -		    (push item res)))
 -	      res)))
 -      (cond (hashtable
 -             (process (nth-value 1 (gethash (apply-key key item) hashtable))))
 -            (t
 -             (process (with-set-keys (member (apply-key key item) list2))))))))
 +	 (list-to-hashtable list2 key test test-not)))
 +    (if hashtable
 +        (process-set nil (nth-value 1 (gethash (apply-key key item) hashtable)))
 +        (process-set nil (with-set-keys (member (apply-key key item) list2))))))
  (defun set-difference (list1 list2 &key key (test #'eql testp) (test-not nil notp))
    "Returns the elements of list1 which are not in list2."
@@ -835,21 +831,10 @@
      (return-from set-difference list1))
    (let ((hashtable
 -	  (list-to-hashtable list2 key test test-not)))
 -    (macrolet
 -        ((process (test-form)
 -           `(let ((res nil))
 -	      (dolist (item list1)
 -	        (if (not ,test-form)
 -                    (push item res)))
 -	      res)))
+-
 -      (cond (hashtable
 -             (process (nth-value 1 (gethash (apply-key key item) hashtable))))
 -            (t
 -	     ;; Default implementation because we didn't create the hash
 -	     ;; table.
 -             (process (with-set-keys (member (apply-key key item) list2))))))))
 +	 (list-to-hashtable list2 key test test-not)))
 +    (if hashtable
 +        (process-set nil (not (nth-value 1 (gethash (apply-key key item) hashtable))))
 +        (process-set nil (not (with-set-keys (member (apply-key key item) list2)))))))
  (declaim (end-block))

Raymond Toy pushed to branch issue-240-clean-up-hashtable-impl at cmucl / cmucl

Commits:

1 changed file:

Changes: