I am curious, with path CLJ-1430 why stop at 3 arguments? Why not unroll to 20?

I ask for a practical reason. In my own library, I have unrolled several 
functions which get called
a lot. Moving from all variadic to non-variadic up to 5 args has produced a 
given a 2x increase in 
my code under extreme circumstances. I was thinking of macro'ing it out to an 
arity of 20, but 
haven't yet, just because it seems a step too far.

Phil


________________________________________
From: clojure@googlegroups.com [clojure@googlegroups.com] on behalf of Alex 
Miller [a...@puredanger.com]
Sent: 27 October 2014 03:42
To: clojure@googlegroups.com; clojure-...@googlegroups.com
Subject: [ANN] Clojure 1.7.0-alpha3 now available

Clojure 1.7.0-alpha3 is now available.

Try it via
- Download: http://central.maven.org/maven2/org/clojure/clojure/1.7.0-alpha3/
- Download securely: 
https://repo1.maven.org/maven2/org/clojure/clojure/1.7.0-alpha3/
- Leiningen: [org.clojure/clojure "1.7.0-alpha3"]

For users of Clojure 1.7.0-alpha2, there have been a few important changes in 
features under development:

Transducers:
- "iteration" function renamed to "eduction"
- Fixed several issues related to reduced values

*unchecked-math* boxed math warnings:
- warnings are now only emitted when (set! *unchecked-math* :warn-on-boxed). 
for old behavior (no warnings), use (set! *unchecked-math* true).

For other changes new in alpha3, see the issues marked "(alpha3)" in the 
changes below.

------------------------------------------------------------
Clojure 1.7.0-alpha3 has the changes below from 1.6.0:

## 1 New and Improved Features

### 1.1 Transducers

Transducers is a new way to decouple algorithmic transformations from their
application in different contexts. Transducers are functions that transform
reducing functions to build up a "recipe" for transformation.

Also see: http://clojure.org/transducers

Many existing sequence functions now have a new arity (one fewer argument
than before). This arity will return a transducer that represents the same
logic but is independent of lazy sequence processing. Functions included are:

* conj (conjs to [])
* map
* mapcat
* filter
* remove
* take
* take-while
* drop
* drop-while
* cycle
* take-nth
* replace
* partition-by
* partition-all
* keep
* keep-indexed

Additionally some new transducer functions have been added:

* cat - concatenates the contents of each input
* de-dupe - removes consecutive duplicated values
* random-sample - returns items from coll with random probability

And this function can be used to make completing transforms:

* completing

There are also several new or modified functions that can be used to apply
transducers in different ways:

* sequence - takes a transformation and a coll and produces a lazy seq
* transduce - reduce with a transformation (eager)
* eduction - returns a reducible/seqable/iterable seq of applications of the 
transducer to items in coll. Applications are re-performed with every 
reduce/seq/iterator.
* run! - run the transformation for side effects on the collection

There have been a number of internal changes to support transducers:

* volatiles - there are a new set of functions (volatile!, vswap!, vreset!, 
volatile?) to create and use volatile "boxes" to hold state in stateful 
transducers. Volatiles are faster than atoms but give up atomicity guarantees 
so should only be used with thread isolation.
* array iterators - added support for iterators over arrays

Some related issues addressed during development:
* [CLJ-1511](http://dev.clojure.org/jira/browse/CLJ-1511)
* [CLJ-1497](http://dev.clojure.org/jira/browse/CLJ-1497)
* [CLJ-1549](http://dev.clojure.org/jira/browse/CLJ-1549) (alpha3)
* [CLJ-1537](http://dev.clojure.org/jira/browse/CLJ-1537) (alpha3)

### 1.2 Keyword and Symbol Construction

In response to issues raised in 
[CLJ-1439](http://dev.clojure.org/jira/browse/CLJ-1439), several changes have 
been made in symbol and keyword construction:

1) The main bottleneck in construction of symbols (which also occurs inside 
keywords) was interning of the name and namespace strings. This interning has 
been removed, resulting in a performance increase.

2) Keywords are cached and keyword construction includes a cache check. A 
change was made to only clear the cache reference queue when there is a cache 
miss.

### 1.3 Warn on Boxed Math

One source of performance issues is the (unintended) use of arithmetic 
operations on boxed numbers. To make detecting the presence of boxed math 
easier, a warning will now be emitted about boxed math if \*unchecked-math* is 
set to :warn-on-boxed (any truthy value will enable unchecked-math, only this 
specific value enables the warning).

Example use:

    user> (defn plus-2 [x] (+ x 2))  ;; no warning, but boxed
#'user/plus-2
    user> (set! *unchecked-math* :warn-on-boxed)
true
    user> (defn plus-2 [x] (+ x 2)) ;; now we see a warning
    Boxed math warning, NO_SOURCE_PATH:10:18 - call: public static 
java.lang.Number
clojure.lang.Numbers.unchecked_add(java.lang.Object,long).
    #'user/plus-2
user> (defn plus-2 [^long x] (+ x 2)) ;; use a hint to avoid boxing
#'user/plus-2

* [CLJ-1325](http://dev.clojure.org/jira/browse/CLJ-1325)
* [CLJ-1535](http://dev.clojure.org/jira/browse/CLJ-1535) (alpha3)

### 1.4 update - like update-in for first level

`update` is a new function that is like update-in specifically for first-level 
keys:

    (update m k f args...)

Example use:

    user> (update {:a 1} :a inc)
{:a 2}
user> (update {:a 1} :a + 2)
{:a 3}
user> (update {} :a identity)  ;; missing returns nil
{:a nil}

* [CLJ-1251](http://dev.clojure.org/jira/browse/CLJ-1251)

## 2 Enhancements

### 2.1 Error messages

* [CLJ-1261](http://dev.clojure.org/jira/browse/CLJ-1261)
  Invalid defrecord results in exception attributed to consuming ns instead of 
defrecord ns
* [CLJ-1169](http://dev.clojure.org/jira/browse/CLJ-1169)
  Report line,column, and source in defmacro errors
* [CLJ-1297](http://dev.clojure.org/jira/browse/CLJ-1297) (alpha3)
  Give more specific hint if namespace with "-" not found to check file uses "_"

### 2.2 Documentation strings

* [CLJ-1417](http://dev.clojure.org/jira/browse/CLJ-1417) (alpha3)
  clojure.java.io/input-stream<http://clojure.java.io/input-stream> has 
incorrect docstring
* [CLJ-1357](http://dev.clojure.org/jira/browse/CLJ-1357) (alpha3)
  Fix typo in gen-class doc-string
* [CLJ-1479](http://dev.clojure.org/jira/browse/CLJ-1479) (alpha3)
  Fix typo in filterv example
* [CLJ-1480](http://dev.clojure.org/jira/browse/CLJ-1480) (alpha3)
  Fix typo in defmulti docstring
* [CLJ-1477](http://dev.clojure.org/jira/browse/CLJ-1477) (alpha3)
  Fix typo in deftype docstring
* [CLJ-1478](http://dev.clojure.org/jira/browse/CLJ-1378) (alpha3)
  Fix typo in clojure.main usage

### 2.3 Performance

* [CLJ-1430](http://dev.clojure.org/jira/browse/CLJ-1430)
  Improve performance of partial with more unrolling
* [CLJ-1384](http://dev.clojure.org/jira/browse/CLJ-1384)
  clojure.core/set should use transients for better performance
* [CLJ-1429](http://dev.clojure.org/jira/browse/CLJ-1429)
  Cache unknown multimethod value default dispatch

### 2.4 Other enhancements

* [CLJ-1191](http://dev.clojure.org/jira/browse/CLJ-1191)
  Improve apropos to show some indication of namespace of symbols found
* [CLJ-1378](http://dev.clojure.org/jira/browse/CLJ-1378)
  Hints don't work with #() form of function
* [CLJ-1498](http://dev.clojure.org/jira/browse/CLJ-1498)
  Removes owner-thread check from transients - this check was preventing some 
valid usage of transients in core.async where a transient is created on one 
thread and then used again in another pooled thread (while still maintaining 
thread isolation).
* [CLJ-803](http://dev.clojure.org/jira/browse/CLJ-803) (alpha3)
  Extracted IAtom interface implemented by Atom.
* [CLJ-1315](http://dev.clojure.org/jira/browse/CLJ-1315) (alpha3)
  Don't initialize classes when importing them
* [CLJ-1330](http://dev.clojure.org/jira/browse/CLJ-1330) (alpha3)
  Class name clash between top-level functions and defn'ed ones

## 3 Bug Fixes

* [CLJ-1362](http://dev.clojure.org/jira/browse/CLJ-1362)
  Reduce broken on some primitive vectors
* [CLJ-1388](http://dev.clojure.org/jira/browse/CLJ-1388)
  Equality bug on records created with nested calls to map->record
* [CLJ-1274](http://dev.clojure.org/jira/browse/CLJ-1274)
  Unable to set compiler options via system properties except for AOT 
compilation
* [CLJ-1241](http://dev.clojure.org/jira/browse/CLJ-1241)
  NPE when AOTing overrided clojure.core functions
* [CLJ-1185](http://dev.clojure.org/jira/browse/CLJ-1185)
  reductions does not check for reduced value
* [CLJ-1039](http://dev.clojure.org/jira/browse/CLJ-1039)
  Using def with metadata {:type :anything} throws ClassCastException during 
printing
* [CLJ-887](http://dev.clojure.org/jira/browse/CLJ-887)
  Error when calling primitive functions with destructuring in the arg vector
* [CLJ-823](http://dev.clojure.org/jira/browse/CLJ-823)
  Piping seque into seque can deadlock
* [CLJ-738](http://dev.clojure.org/jira/browse/CLJ-738)
  <= is incorrect when args include Double/NaN
* [CLJ-1408](http://dev.clojure.org/jira/browse/CLJ-1408) (alpha3)
  Make cached string value of Keyword and Symbol transient
* [CLJ-1466](http://dev.clojure.org/jira/browse/CLJ-1466) (alpha3)
  clojure.core/bean should implement Iterable




--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your 
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups 
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to 
clojure+unsubscr...@googlegroups.com<mailto:clojure+unsubscr...@googlegroups.com>.
For more options, visit https://groups.google.com/d/optout.

-- 
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your 
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to