gmane.lisp.alexandria.devel

Implementation of DELETE-FROM-PLIST

Robert Smith — 2013-02-23T09:09:05

Hey:

Here's a destructive/non-consing version of DELETE-FROM-PLIST. I've
tested with (I think) all corner cases from the REPL, but I ought to
write tests proper.

The function is here http://tinyurl.com/adqkssu ;or the following huge
link, in case the last one is invalidated
https://bitbucket.org/tarballs_are_good/lisp-random/src/3db634111d35e788c6ea2f4a1b3ab38334e24cde/miscellaneous_exercises/delete-from-plist.lisp?at=default#cl-30
.

For simplicity or ease of review from an email client, I've pasted the
function at the end of this email.

Additionally, this function would make it pretty easy to write
DELETE-FROM-PLIST-IF{-NOT}, since the function to determine if a key
is bad is factored out. If one did write this function, then it would
be easy to define DELETE-FROM-PLIST in terms of it.

Let me know if there are any changes that should be made.

Cheers,

Robert Smith


;;;; from delete-from-plist.lisp

(defun delete-from-plist (plist &rest keys)
  "Delete all keys and pairs indicated by KEYS from the pli

Bug in gaussian-random

Andy Peterson — 2013-02-04T18:14:13

Hello,

Four months ago, I reported a bug in gaussian-random when either optional
parameter min or max is nil but not both are nil. The docstring has been
modified since then but the code is still the same and the bug remains. In
such a situation it is possible to enter an infinite loop.

This is easy to demonstrate by the call (gaussian-random 0 nil). You may
need to repeat the call a few times because the bug depends on the values
returned by the first call to the local function gauss.  An infinite loop
will occur if gauss returns a negative number.

I have attached a patch which fixes the bug.

Sincerely,

Andy Peterson
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More open development

Faré — 2013-01-26T16:47:33

On Sat, Jan 26, 2013 at 9:14 AM, Nikodemus Siivola
<nikodemus< at >random-state.net> wrote:
Maybe alexandria needs more people with commit rights?

Or else, maybe we need a different reference library that will have
a more open development style.

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
Government's view of the economy could be summed up in a few short phrases :
If it moves, tax it. If it keeps moving, regulate it. And if it stops
moving, subsidize it. — Ronald Reagan (1986)

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flatten depth param

Garrett Kolpin — 2013-01-16T04:29:54

Hi,

I've found it useful to be able to specify a depth when flattening a list
structure. The attached patch adds a :to-depth keyword parameter to the
flatten function. For instance,

(flatten '((a b) (c (d)) :to-depth 1) => (a b c (d))

Is this something that could be added?

Thanks,
-Garrett
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if-let*

Marco Baringer — 2012-11-24T16:59:43

(i think i've already sent this, but it hasn't shown up on the list,
sorry if you get it twice)

hi,

  i recently needed (or just decided that i wanted it) a version of
  if-let with sequential binding. The bindings form is as with if-let,
  however to ensure that only the 'true' bindings are seen in the else
  form (and i'm not convinced this is worth it) the else form is
  repeated multiple times (once per binding) in the macro's expansion.

  the docstring should explain how it works (and if not i'll fix the
  docstring).

  and, since it made sense to me at the time, when-let and when-let* are
  implemented in terms of if-let and if-let* (instead of repeating the
  binding expansion and and code).



--
-marco
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multiple values in switch clauses

Marco Baringer — 2012-11-22T08:02:02

hi,

  i'd like switch to, just like case and typecase do, allow multiple
  values in the 'value' position of the condition:

  (switch (foo)
    ((bar baz) ...))

  So the attached patch checks for the key form being a cons and, if so,
  expands into a (member value :test test) instead of (test value)
  form. Of course, this means that your key values can no longer be
  forms, so this may break existing code. I don't have any code which
  actually uses a function call in the value form of the clause (and a
  quick grep over my locally installed lisp libs shows nobody else does
  either), so i'm ok with the change, but i can understand if others
  don't agree.



--
-marco
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Add SUBDIVIDE to alexandria

Rolando Pereira — 2012-10-19T10:19:11

Hello all,

What are the odds of adding this[1] implementation of SUBDIVIDE to
alexandria?

I understand that alexandria only accepts public domain code, but I
think that Robert Smith also follows this mailist so maybe he would
let the code be added to alexandria.

SUBDIVIDE is a function that divides a sequence into parts with a
certain size, and returns a list with those parts.

Best Regards,
Rolando Pereira

---
Links:

[1] - https://bitbucket.org/tarballs_are_good/qtility/src/423519bbe130/sequence.lisp#cl-29

spelling mistake onhttp://common-lisp.net/project/alexandria/

Michael Stevens — 2012-10-14T13:23:49

Hi.

http://common-lisp.net/project/alexandria/ 

has a reference to "draft documantion exists" when it probably means
"draft documentation" exists?

Michael

minor spelling patch

Michael Stevens — 2012-10-14T13:22:24

Minor spelling improvements in README.
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Bug in gaussian-random

Andy Peterson — 2012-10-01T18:44:34

function: gaussian-random (&optional min max)

If gaussian-random is called with a value for min and nil for max (or vice
versa), the function could enter an infinite loop.

example (gaussian-random 100 nil)  almost always causes an infinite loop.

If the first call to the local function "gauss" creates a value that does
not satisify min,
then the local function "guard" enters an infinite loop because guard is
called with a value for max that is less than min.

Sincerely,

Andy Peterson
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Adding a taste of Scheme to CL

Pierre Thierry — 2012-08-02T02:41:39

Hi,

after having followed SICP, I have been irremediably hooked on
Scheme's let, so I added it to my macros. IIRC, I borrowed this
implementation form SBCL's NAMED-LET (it's so short, it's hard to
tell).

I also heavily use a cataphoric IF, which I will now replace by the
single-binding IF-LET, now that I know it exists.

I thought it would be nice if LET< at > was available in Alexandria with
the other binding macros.

Regards,
Pierre

parse-ordinary-lambda-list

Faré — 2012-07-23T17:32:49

An important missing information that parse-ordinary-lambda-list fails
to return is whether there was a &key keyword.
If I submit a patch to add that as an additional returned value, will
it be integrated?

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
The American diplomat to the Russian: "My country too is free: in the USA too
anyone may freely publish the dirty little secrets of president Medvedev!"

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Regarding %MULTIPLY-RANGE, BINOMIAL-COEFFICIENT

Robert Smith — 2012-06-30T21:41:58

Hello all.

I've been trying to speed up BINOMIAL-COEFFICIENT for combinatorial
calculations and ended up writing my own functions which were
originally based off of Alexandria's design. For computing the
binomial coefficient of (10^11, 10^5), Alexandria's takes about 9.990
seconds on my 64-bit Windows machine with a relatively recent SBCL
with (optimize speed (safety 0) (debug 0)).

I've ended up writing my own version of %MULTIPLY-RANGE, which I ended
up calling RANGE-PRODUCT, and it's definition is:

(declaim (ftype (function (integer integer) integer) range-product))
(defun range-product (lower upper)
  "Compute LOWER * (LOWER+1) * ... * (UPPER-1) * UPPER."
  (assert (<= lower upper))
  (case (- upper lower)
    ((0) lower)
    ((1) (* lower upper))
    (otherwise (let ((mid (floor (+ lower upper) 2)))
                 (* (range-product lower mid)
                    (range-product (1+ mid) upper))))))

[ from QTILITY:
https://bitbucket.org/tarballs_are_good/qtility/src/65eff10fdece/arithmetic.lisp#cl-43

Documentation fix and feature suggestion

Jan Moringen — 2012-06-19T09:09:19

Dear alexandria developers,

please the documentation fix and new functions in the two most recent
commits in

  git://github.com/scymtym/alexandria.git

for inclusion. Many thanks in advance.

Kind regards,
Jan

starts-with-subseq buggy

Nikodemus Siivola — 2012-06-02T15:38:22

Note to self:

[18:17]  <yates> pjb: yes, i did read that
[18:17]  <adeht> alexandria:starts-with-subseq is terribly buggy :(
[18:19]  * KognizantKog (~user< at >72.168.55.98) has joined #lisp
[18:20]  <yates> pjb: have you read
http://www.lispworks.com/documentation/HyperSpec/Body/26_glo_s.htm#satisfy_the_test
[18:20]  <yates> ?
[18:21]  <yates> do you disagree with the definition?
[18:23]  * teggi (~teggi< at >113.172.40.96) has joined #lisp
[18:24]  <fe[nl]ix> adeht: how so ?
[18:25]  <adeht> fe[nl]ix, for example you'd expect
(starts-with-subseq "foo" "oop" :start1 1) to return true... but (i)
it passes args to mismatch in the reverse order so start1 becomes
start2 and (ii) it compares the result of mismatch to the whole
prefix's length, so returns false

Cheers,

 -- Nikodemus

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Nesting

Faré — 2012-05-26T20:43:18

I've found the following definitions incredibly useful in
(nest) allowing indentation to not get out of hand
(nest) getting the good feeling of that binding has other languages
(tsen) focusing on the thing at hand, not the intermediate definitions needed
(tsen) "piping" results into a series of functions or forms.

I don't like the name "tsen", though. "wrap" comes to mind.
Maybe you have better suggestions.

;;; Nesting binding forms (from a suggestion by marco baringer)
(defmacro with-nesting ((&key (from-end t)) &rest things)
  (if from-end `(nest ,< at >things) `(tsen ,< at >things)))

(defmacro nest (&rest things)
  (reduce #'(lambda (outer inner) (append outer (list inner)))
          things :from-end t))

(defmacro tsen (&rest things)
  (reduce #'(lambda (inner outer) (append outer (list inner)))
          things :from-end nil))

In any case, I'd like these to become a standard part of alexandria.

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
Gauss, when asked how

[Patch]: Fix an example in the docstring of iota.

Stas Boukarev — 2012-05-15T20:57:22

An example in the docstring of iota was
(iota 4) => (0 1 2 3 4)
while it should've been
(iota 4) => (0 1 2 3).

Split up Alexandria into an additionalexperimental package?

Tobias C Rittweiler — 2012-04-26T09:43:44

What is a good way to handle new additions to Alexandria that
are not fully fledged out yet?

As Hans noticed himself over this week, it usually takes
an incredible amount of time and effort to come up with
something with complete semantics. Time is a scarce resource,
and even if it was not, only experience and actual usage will
discover edges cases.

Common Lisp itself has been tried out and implemented many
times during the standardization process itself which is one
of the reasons it's engineered as well as it is.


What about providing an :ALEXANDRIA.EXPERIMENTAL
package that uses :ALEXANDRIA? New additions
go into the experimental package which is advertised
not necessarily to be fully backwards compatible.

People can explicitly :IMPORT-FROM that package (which
will continue to work even when the symbol moves from there
into :ALEXANDRIA, assuming no incompatible changes have been
made.)

T

DESTRUCTURE-CLAUSES -alexandria_destruct#9CF676.diff (1/1)

Tobias C Rittweiler — 2012-04-25T13:47:04

I was pleased to discover that DESTRUCTURING-CASE made it into
Alexandria meanwhile. Very nice! This allows me to share the
little gem that I'm attaching with this posting. It's a handy
macro to make writing macros like DEFPACKAGE, DEFGENERIC of
DEFREADTABLE easy like a breeze.

Happy to be giving back again! :-)

T
diff --git a/macros.lisp b/macros.lisp
index 4450435..0d4b9e9 100644
--- a/macros.lisp
+++ b/macros.lisp
< at >< at > -303,4 +303,76 < at >< at > Example:
   (setf (documentation name 'function) (documentation 'destructuring-case 'function)))
 
 
+;;; DESTRUCTURE-CLAUSES
 
+(defmacro destructure-clauses (clauses patterns &body body)
+  "Utility macro to conveniently destructure DEFPACKAGE like clauses.
+
+     clauses  ::= clause*
+     clause   ::= (keyword . list)                  ; e.g. (:FOO 1 :K 2)
+
+     patterns ::= pattern*
+     pattern  ::= (keyword . ordinary-lambda-list)  ; e.g. (:FOO N &KEY K)
+
+The CAR of each clause in CLAUSES will be tried to be matched against
+the CAR of each pattern in PATTERNS.

EXTREMUM

Tobias C Rittweiler — 2012-04-25T09:15:59

The cl-utilities library contains one function which cannot be
found in alexandria that necessity pops up every now and then:

  Returning the maximum (or minimum) element in a sequence
  with respect to an arbitrary calculation involving the elements.

I.e.

  (elt (sort (copy-sequence <SEQUENCE>) #'< :key <FUNCTION>) 0) ; or #'>

except doing it more efficiently.

CL-UTILITIES calls this function EXTREMUM. (It also provides a couple
of more functions along the lines to cover some edge cases.)

The code can be found here:
 
http://common-lisp.net/viewvc/cl-utilities/cl-utilities/extremum.lisp?rev
ision=1.10&view=markup

As the code is Public Domain, it could just be moved as is.


I find no other use of cl-utilities and would like to see it
become entirely obsolete.

T

Some number patches

Robert Smith — 2012-04-25T03:03:10

Hello all:

I've decided I'm going to try to merge in stuff from my QTILITY
library [1] in an attempt to reduce the number of utility libraries
out there -- provided the stuff fits with the goals of Alexandria.
Xach and I decided it's best not to add more utility libraries to
Quicklisp.

I've created a patch that adds MULF and DIVF, which do what you might
expect (modify macros for * and /). I also added some numerical
predicates that I myself like, as well as others: POSITIVEP,
NEGATIVEP, NON-POSITIVE-P, NON-NEGATIVE-P, NON-ZERO-P. As you might
notice, they sound especially familiar to those who read mathematics
literature.

Also, would it be possible for me to have push permissions?

I hope you'll take these attached patches into consideration.

Thanks,

Robert Smith


[1] https://bitbucket.org/tarballs_are_good/qtility/src
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