March 2008 - alexandria-devel - mailman3.common-lisp.net

[alexandria-devel] darcs patch: Add #.#+ readtime conditional functions.
by asf＠boinkor.net 02 Oct '09

02 Oct '09

Mon Oct 16 10:00:31 CEST 2006 asf(a)boinkor.net * Add #.#+ readtime conditional functions. * This adds functions that can be used in #+#. readtime conditionals, for example: #+#.(alexandria:read-if (find-package :asdf-install)) :yay #+#.(alexandria:read-if-fbound :install :asdf-install :exportedp t) :yay * included in the patch is a commented-out portion that allows the user to activate a #? read syntax. I'm not sure if that fits into the conservativism constraints.

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[alexandria-devel] length=1
by Attila Lendvai 27 May '08

27 May '08

dear list, is there any objections against this? (declaim (inline length=1)) (defun length=1 (sequence) (if (listp sequence) (and sequence (null (rest sequence))) (= 1 (length sequence)))) in optimized code, where type information is available, it drops the type check. and otherwise it works for sequences and is fast for lists. maybe it could be extended into two functions: length= and length=1, where length= optimizes for lists using nthcdr. -- attila

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[alexandria-devel] [PATCH] COPY-HASH-TABLE
by Tobias C. Rittweiler 04 Apr '08

04 Apr '08

The following patch adds a :COPY-FN &key arg to COPY-HASH-TABLE which defaults to CL:IDENTITY. This way, you can specify if you want a shallow copy (default), or a customized one which is possibly deep to some arbitrary level. -T.

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[alexandria-devel] UNWIND-PROTECT-CASE
by Tobias C. Rittweiler 27 Mar '08

27 Mar '08

Sometimes it's desired to only do a certain cleanup operating in an UNWIND-PROTECT if a true transfer-of-control was issued in the protected-form. UNWIND-PROTECT-CASE can be used to conveniently control on what circumstances cleanup operations are supposed to be performed. (I think I've seen UNWIND-PROTECT-CASE on one of the Lisp machines, so it's actually prior art.) -T. (defmacro unwind-protect-case ((&optional abort-flag) protected-form &body clauses) "Like CL:UNWIND-PROTECT, but you can specify the circumstances that the cleanup CLAUSES are run. ABORT-FLAG is the name of a variable that will be bound to T in CLAUSES if the PROTECTED-FORM aborted preemptively, and to NIL otherwise. Examples: (unwind-protect-case () (protected-form) (:normal (format t \"This is only evaluated if PROTECTED-FORM executed normally.~%\")) (:abort (format t \"This is only evaluated if PROTECTED-FORM aborted preemptively.~%\")) (:always (format t \"This is evaluated in either case.~%\"))) (unwind-protect-case (aborted-p) (protected-form) (:always (perform-cleanup-if aborted-p))) " (check-type abort-flag (or null symbol)) (let ((gflag (gensym "FLAG+"))) `(let ((,gflag t)) (unwind-protect (multiple-value-prog1 ,protected-form (setf ,gflag nil)) (let ,(and abort-flag `((,abort-flag ,gflag))) ,@(loop for (cleanup-kind . forms) in clauses collect (ecase cleanup-kind (:normal `(when (not ,gflag) ,@forms)) (:abort `(when ,gflag ,@forms)) (:always `(progn ,@forms)))))))))

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[alexandria-devel] remove-from-plist
by Michael Weber 14 Mar '08

14 Mar '08

Below are three different implementations of remove-from-plist, all of which I find more aestetic than current alexandria's implementation. YMMV. I would favor the first one, which explicitly ditches error checking ("it's user responsibility", and a proper plist will be returned). In case somebody disagrees, the second implementation reintroduces it, albeit with a better error message. The third implementation checks for properness only at the end (outside the loop), while still being shorter than alexandria's implementation. I would also remove the FIXME, on grounds that if plists are long enough for that to matter, one shouldn't be using them anyway. (defun remove-from-plist (plist &rest keys) (loop for (key value) on plist by #'cddr unless (member key keys :test #'eq) collect key and collect value)) (defun remove-from-plist (plist &rest keys) (loop for (key . rest) on plist by #'cddr do (assert rest () "Expected a proper plist, got ~S" plist) unless (member key keys :test #'eq) collect key and collect (first rest))) (defun remove-from-plist (plist &rest keys) (loop with last = t for (key . rest) on plist by #'cddr do (setf last rest) unless (member key keys :test #'eq) collect key and collect (first rest) finally (assert last () "Expected a proper plist, got ~S" plist))) Cheers, Michael

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[alexandria-devel] Latest patches pullable from my new darcs repo
by Tobias C. Rittweiler 11 Mar '08

11 Mar '08

All the latest patches, and some more, are pullable via darcs pull http://common-lisp.net/~trittweiler/darcs/alexandria/ For your convenience, -T.

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[alexandria-devel] cdr 5
by Attila Lendvai 11 Mar '08

11 Mar '08

dear list, any objections against adding the types listed in cdr 5 to alexandria? it already has array-index and the rest seems useful, too. http://cdr.eurolisp.org/document/5/extra-num-types.html if noone does that before me and there's no objection either, i'll push it eventually. -- attila

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[alexandria-devel] [PATCH] fix docstring typos in numbers.lisp
by Tobias C. Rittweiler 11 Mar '08

11 Mar '08

--- old-alexandria/numbers.lisp 2008-03-10 17:42:17.000000000 +0100 +++ new-alexandria/numbers.lisp 2008-03-10 17:42:17.000000000 +0100 @@ -44,7 +44,7 @@ (defun iota (n &key (start 0) (step 1)) "Return a list of n numbers, starting from START (with numeric contagion from STEP applied), each consequtive number being the sum of the previous one -and STEP. START defaults to 0 and STEP to 0. +and STEP. START defaults to 0 and STEP to 1. Examples: @@ -62,13 +62,14 @@ (defun map-iota (function n &key (start 0) (step 1)) "Calls FUNCTION with N numbers, starting from START (with numeric contagion from STEP applied), each consequtive number being the sum of the previous one -and STEP. START defaults to 0 and STEP to 0. Returns N. +and STEP. START defaults to 0 and STEP to 1. Returns N. Examples: - (iota 4) => (0 1 2 3 4) - (iota 3 :start 1 :step 1.0) => (1.0 2.0 3.0) - (iota 3 :start -1 :step -1/2) => (-1 -3/2 -2) + (map-iota #'print 3 :start 1 :step 1.0) => 3 + ;;; 1.0 + ;;; 2.0 + ;;; 3.0 " (declare (type (integer 0) n) (number start step)) (loop repeat n

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[alexandria-devel] [PATCH] improvement wrt. signalling errors on improper sequences
by Tobias C. Rittweiler 11 Mar '08

11 Mar '08

The attached patch improves error signalling when passing improper lists to some of the sequence function where the docstring said that they'd signal an error. Additionally, introduce the macro DO-PROPER-LIST, and the function PROPER-LIST-LENGTH -- which are used to remove some code duplication. -T.

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[alexandria-devel] ENSUREF
by Tobias C. Rittweiler 10 Mar '08

10 Mar '08

ENSUREF can be used to initialize &key and &optional key args more conveniently. Another name would be ORF, which looks funny to my eyes. Another name would be INITIALIZEF, but this might open questions regarding its relation to the object initialization machinery. -T. (defmacro ensuref (place thing &rest more &environment env) "If PLACE evaluates to NIL, set it to THING. Otherwise, let it unchanged. Examples: (let ((a nil) (b :foo) (c (list 1 2 nil 4))) (ensuref a :a b :b (third c) :c) (values a b c)) ==> :A, :FOO, (1 2 :C 4) Notes: (ENSUREF PLACE THING) is approximately equivalent to (SETF PLACE (OR PLACE THING)) except that ENSUREF ensures (no pun indented) that PLACE is evaluated only once, and except that PLACE isn't set at all if it evaluated to NIL. (E.g. as a result, auxiliary methods of (setf foo) generic functions aren't run in that case.) " (multiple-value-bind (gvars vals gstorevars setter getter) (get-setf-expansion place env) (when (second gstorevars) (error "ENSUREF does not support setting multiple values ~ via the (VALUES ...) place.")) (if (null more) (let ((gstorevar (first gstorevars)) (gtmp (gensym "CURVAL+"))) `(let ,(mapcar #'list gvars vals) (let ((,gtmp ,getter)) (if ,gtmp ,gtmp (let ((,gstorevar ,thing)) ,setter))))) `(progn (ensuref ,place ,thing) (ensuref ,@more)))))

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