From: Andrea Corallo <akrl@sdf.org>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: Nicolas Petton <nicolas@petton.fr>, emacs-devel@gnu.org
Subject: Re: [PATCH] extend map-into
Date: Sun, 06 Oct 2019 20:59:50 +0000 [thread overview]
Message-ID: <xjfd0f9h9o9.fsf@sdf.org> (raw)
In-Reply-To: <jwv1rvqrncz.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Sun, 06 Oct 2019 10:02:54 -0400")
[-- Attachment #1: Type: text/plain, Size: 1174 bytes --]
Stefan Monnier <monnier@iro.umontreal.ca> writes:
> [ I added Nicolas explicitly in the list, in case he's too busy to read
> all messages. ]
>
>> would a solution like the one in attached patch do the job?
>
> Yes and no: it does the job, but only for `map-into`. So that doesn't
> immediately cover the needs of `map-merge` and other callers of
> `map-into` (e.g. the `map-values-apply` I suggested which would return
> a new map).
>
> I guess we could use a `type` that's not a symbol but a list (whose
> head is a symbol and the rest are the args), but it could be a bit
> inconvenient (and would impact efficiency as well because it makes the
> cl-generic dispatch more complex).
Cool, is the attached patch doing what you suggest?
> On a related note, maybe it would be good to have map.el primitives that
> let you create a new map of the same type as another (preserving :test).
>
>> + (let* ((h-args (if keyword-args
>> + keyword-args
>> + (list :size (map-length map) :test 'equal)))
>
> Aka (or keyword-args (list :size (map-length map) :test 'equal))
>
ops :D
> Stefan
>
Bests
Andrea
--
akrl@sdf.org
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From 55780be0af0e8443fb9b14b77cb3d13ca9af75fb Mon Sep 17 00:00:00 2001
From: Andrea Corallo <akrl@sdf.org>
Date: Sun, 6 Oct 2019 22:43:11 +0200
Subject: [PATCH] Extend 'map-into' for better control on hash table creation.
---
etc/NEWS | 4 ++++
lisp/emacs-lisp/map.el | 29 +++++++++++++++++++++--------
2 files changed, 25 insertions(+), 8 deletions(-)
diff --git a/etc/NEWS b/etc/NEWS
index c8cc753..5942a32 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -24,6 +24,10 @@ applies, and please also update docstrings as needed.
\f
* Installation Changes in Emacs 27.1
+** Extend function 'map-into'.
+Add a 'map-into' method to have hash table creation parameters
+tweak-able.
+
** Emacs now uses GMP, the GNU Multiple Precision library.
By default, if 'configure' does not find a suitable libgmp, it
arranges for the included mini-gmp library to be built and used.
diff --git a/lisp/emacs-lisp/map.el b/lisp/emacs-lisp/map.el
index 54e802e..dfc1500 100644
--- a/lisp/emacs-lisp/map.el
+++ b/lisp/emacs-lisp/map.el
@@ -338,7 +338,8 @@ map-every-p
t))
(defun map-merge (type &rest maps)
- "Merge into a map of type TYPE all the key/value pairs in MAPS."
+ "Merge into a map of type TYPE all the key/value pairs in MAPS.
+See `map-into' for all supported values of TYPE."
(let ((result (map-into (pop maps) type)))
(while maps
;; FIXME: When `type' is `list', we get an O(N^2) behavior.
@@ -354,7 +355,8 @@ map-merge-with
"Merge into a map of type TYPE all the key/value pairs in MAPS.
When two maps contain the same key (`eql'), call FUNCTION on the two
values and use the value returned by it.
-MAP can be a list, hash-table or array."
+MAP can be a list, hash-table or array.
+See `map-into' for all supported values of TYPE."
(let ((result (map-into (pop maps) type))
(not-found (cons nil nil)))
(while maps
@@ -458,17 +460,28 @@ map-do
(funcall function index elt))
array))
-(cl-defmethod map-into (map (_type (eql hash-table)))
- "Convert MAP into a hash-table."
- ;; FIXME: Just knowing we want a hash-table is insufficient, since that
- ;; doesn't tell us the test function to use with it!
- (let ((ht (make-hash-table :size (map-length map)
- :test 'equal)))
+(defsubst map--into-hash (map keyword-args)
+ "Convert MAP into a hash-table.
+KEYWORD-ARGS are forwarded to `make-hash-table'."
+ (let ((ht (apply #'make-hash-table keyword-args)))
(map-apply (lambda (key value)
(setf (map-elt ht key) value))
map)
ht))
+(cl-defmethod map-into (map (_type (eql hash-table)))
+ "Convert MAP into a hash-table."
+ (map--into-hash map (list :size (map-length map) :test 'equal)))
+
+(cl-defmethod map-into (map (args (head hash-table)))
+ "Convert MAP into a hash-table.
+ARGS is a list where the car is 'hash-table' and the cdr are the keyword-args
+ forwarded to `make-hash-table'.
+
+Example:
+ (map-into '((1 . 3)) '(hash-table :test eql))"
+ (map--into-hash map (cdr args)))
+
(defun map--make-pcase-bindings (args)
"Return a list of pcase bindings from ARGS to the elements of a map."
(seq-map (lambda (elt)
--
2.7.4
next prev parent reply other threads:[~2019-10-06 20:59 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 9:58 new function proposal alist-to-hash Andrea Corallo
2019-10-04 19:16 ` Stefan Monnier
2019-10-05 8:18 ` Andrea Corallo
2019-10-05 15:13 ` Stefan Monnier
2019-10-05 15:45 ` Andrea Corallo
2019-10-05 8:28 ` [PATCH] extend map-into (was: new function proposal alist-to-hash) Andrea Corallo
2019-10-06 14:02 ` [PATCH] extend map-into Stefan Monnier
2019-10-06 20:59 ` Andrea Corallo [this message]
2019-10-08 17:29 ` Stefan Monnier
2019-10-08 18:46 ` Andrea Corallo
2019-10-08 20:23 ` Stefan Monnier
2019-10-09 15:35 ` Andrea Corallo
2019-10-09 19:41 ` Stefan Monnier
2019-10-09 20:02 ` Andrea Corallo
2019-10-10 8:27 ` Nicolas Petton
2019-10-10 8:28 ` Nicolas Petton
2019-10-10 10:06 ` Andrea Corallo
2019-10-10 11:47 ` Nicolas Petton
2019-10-11 16:19 ` Stefan Monnier
2019-10-11 16:29 ` Andrea Corallo
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