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
- take-nth
- replace
- partition-by
- partition-all
- keep
- keep-indexed
- map-indexed
- distinct
- interpose
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/iterable of applications of the transducer to items in coll. Applications are re-performed with every reduce/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
- CLJ-1497
- CLJ-1549
- CLJ-1537
- CLJ-1554
- CLJ-1601
- CLJ-1606
- CLJ-1621
- CLJ-1600
- CLJ-1635
- CLJ-1683
- CLJ-1669
Reader Conditionals are a new capability to support portable code that can run on multiple Clojure platforms with only small changes. In particular, this feature aims to support the increasingly common case of libraries targeting both Clojure and ClojureScript.
Code intended to be common across multiple platforms should use a new supported file extension: ".cljc". When requested to load a namespace, the platform-specific file extension (.clj, .cljs) will be checked prior to .cljc.
A new reader form can be used to specify "reader conditional" code in cljc files (and only cljc files). Each platform defines a feature identifying the platform (:clj, :cljs, :cljr). The reader conditional specifies code that is read conditionally based on the feature/
Form #? takes a list of alternating feature and expression. These are checked like cond and the selected expression is read and returned. Other branches are unread. If no branch is selected, the reader reads nothing (not nil, but literally as if reading ""). An optional ":default" branch can be used as a fallthrough.
Reader conditional with 2 features and a default:
#?(:clj Double/NaN
:cljs js/NaN
:default nil)
There is also a reader conditional splicing form. The evaluated expression should be sequential and will be spliced into the surrounded code, similar to unqoute-splicing.
For example:
[1 2 #?@(:clj [3 4] :cljs [5 6])]
This form would read as [1 2 3 4] on Clojure, [1 2 5 6] on ClojureScript, and [1 2] on any other platform.
Additionally, the reader can now be invoked with options for the features to use and how to interpret reader conditionals. By default, reader conditionals are not allowed, but that can be turned on, or a "preserve" mode can be used to preserve all branches (most likely useful for tooling or source transforms).
In the preserve mode, the reader conditional itself and any tagged literals within the unselected branches are returned as tagged literal data.
For more information, see: http://dev.clojure.org/display/design/Reader+Conditionals
In response to issues raised in CLJ-1439, several changes have been made in symbol and keyword construction:
-
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.
-
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.
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
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}
Several important Clojure functions now return sequences that also contain fast reduce() (or in some cases iterator()) paths. In many cases, the new implementations are also faster for lazy sequences
- repeat - now implements IReduce
- cycle - implements IReduceInit
- iterate - implements IReduceInit
- range - implements IReduce, specialized case handles common case of all longs
- keys - iterates directly over the keys of a map, without seq or MapEntry allocation
- vals - iterates directly over the vals of a map, without seq or MapEntry allocation
- iterator-seq - creates a chunked sequence when previously it was unchunked
Additionally, hash-maps and hash-sets now provide iterators that walk the data structure directly rather than via a sequence.
A new interface (IMapIterable) for direct key and val iterators on maps was added. External data structures can use this interface to provide direct key and val iterators via keys and vals.
These enhancements are particularly effective when used in tandem with transducers via transduce, sequence, into, and eduction.
There have been enhancements in how the REPL prints values without a print-method, specifically Throwable and the fallthrough Object case. Both cases now print in a tagged literal data form that can be read by the reader.
Unhandled objects print with the class, hash code, and toString:
user=> *ns*
#object[clojure.lang.Namespace 0x55aa628 "user"]
Thrown exceptions will still be printed in the normal way by the default REPL but printing them to a stream will show a different form:
user=> (/ 1 0)
ArithmeticException Divide by zero clojure.lang.Numbers.divide (Numbers.java:158)
user=> (println *e)
#error {
:cause Divide by zero
:via
[{:type java.lang.ArithmeticException
:message Divide by zero
:at [clojure.lang.Numbers divide Numbers.java 158]}]
:trace
[[clojure.lang.Numbers divide Numbers.java 158]
[clojure.lang.Numbers divide Numbers.java 3808]
;; ... elided frames
]}
Additionally, there is a new function available to obtain a Throwable as
map data: Throwable->map.
- CLJ-1261 Invalid defrecord results in exception attributed to consuming ns instead of defrecord ns
- CLJ-1169 Report line,column, and source in defmacro errors
- CLJ-1297 Give more specific hint if namespace with "-" not found to check file uses "_"
- CLJ-1417 clojure.java.io/input-stream has incorrect docstring
- CLJ-1357 Fix typo in gen-class doc-string
- CLJ-1479 Fix typo in filterv example
- CLJ-1480 Fix typo in defmulti docstring
- CLJ-1477 Fix typo in deftype docstring
- CLJ-1478 Fix typo in clojure.main usage
- CLJ-1430 Improve performance of partial with more unrolling
- CLJ-1384 clojure.core/set should use transients for better performance
- CLJ-1429 Cache unknown multimethod value default dispatch
- CLJ-1529 Reduce compile times by avoiding unnecessary calls to Class.forName()
- CLJ-1546 vec is now faster on almost all inputs
- CLJ-1618 set is now faster on almost all inputs
- CLJ-1695 Fixed reflection call in variadic vector-of constructor
- CLJ-1191 Improve apropos to show some indication of namespace of symbols found
- CLJ-1378 Hints don't work with #() form of function
- 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 Extracted IAtom interface implemented by Atom.
- CLJ-1315 Don't initialize classes when importing them
- CLJ-1330 Class name clash between top-level functions and defn'ed ones
- CLJ-1349 Update to latest test.generative and add dependency on test.check
- CLJ-1546 vec now works with things that only implement Iterable or IReduceInit
- CLJ-1618 set now works with things that only implement Iterable or IReduceInit
- CLJ-1633 PersistentList/creator doesn't handle ArraySeqs correctly
- CLJ-1589 Clean up unused paths in InternalReduce
- CLJ-1677 Add setLineNumber() to LineNumberingPushbackReader
- CLJ-1667 Change test to avoid using hard-coded socket port
- CLJ-1683 Change reduce tests to better catch reduce without init bugs
- CLJ-1362 Reduce broken on some primitive vectors
- CLJ-1388 Equality bug on records created with nested calls to map->record
- CLJ-1274 Unable to set compiler options via system properties except for AOT compilation
- CLJ-1241 NPE when AOTing overrided clojure.core functions
- CLJ-1185 reductions does not check for reduced value
- CLJ-1039 Using def with metadata {:type :anything} throws ClassCastException during printing
- CLJ-887 Error when calling primitive functions with destructuring in the arg vector
- CLJ-823 Piping seque into seque can deadlock
- CLJ-738 <= is incorrect when args include Double/NaN
- CLJ-1408 Make cached string value of Keyword and Symbol transient
- CLJ-1466 clojure.core/bean should implement Iterable
- CLJ-1578 Make refer of Clojure core function not throw exception on reload
- CLJ-1501 LazySeq equals() should not use equiv() logic
- CLJ-1572 into (and other fns that rely on reduce) require only IReduceInit
- CLJ-1619 PersistentVector now directly implements reduce without init
- CLJ-1580 Transient collections should guarantee thread visibility
- CLJ-1590 Some IReduce/IReduceInit implementors don't respect reduced
- CLJ-979 Clojure resolves to wrong deftype classes when AOT compiling or reloading
- CLJ-1636 Fix intermittent SeqIterator problem by removing use of this as a sentinel
- CLJ-1637 Fix regression from CLJ-1546 that broke vec on MapEntry
- CLJ-1663 Fix regression from CLJ-979 for DynamicClassLoader classloader delegation
- CLJ-1604 Fix error from AOT'ed code defining a var with a clojure.core symbol name
- CLJ-1561 Fix incorrect line number reporting for error locations
- CLJ-1568 Fix incorrect line number reporting for error locations
- CLJ-1638 Fix regression from CLJ-1546 removed PersistentVector.create(List) method
- CLJ-1681 Fix regression from CLJ-1248 (1.6) in reflection warning with literal nil argument
Clojure now builds with Java SE 1.6 and emits bytecode requiring Java SE 1.6 instead of Java SE 1.5. [CLJ-1268]
The embedded version of the ASM bytecode library has been upgraded to ASM 4.1. [CLJ-713]
The following features are no longer marked Alpha in Clojure:
- Watches - add-watch, remove-watch
- Transients - transient, persistent!, conj!, assoc!, dissoc!, pop!, disj!
- Exception data - ex-info, ex-data
- Promises - promise, deliver
- Records - defrecord
- Types - deftype
- Pretty-print tables - print-table
The clojure.java.api package provides a minimal interface to bootstrap Clojure access from other JVM languages. It does this by providing:
- The ability to use Clojure's namespaces to locate an arbitrary var, returning the var's clojure.lang.IFn interface.
- A convenience method read for reading data using Clojure's edn reader.
IFns provide complete access to Clojure's APIs. You can also access any other library written in Clojure, after adding either its source or compiled form to the classpath.
The public Java API for Clojure consists of the following classes and interfaces:
- clojure.java.api.Clojure
- clojure.lang.IFn
All other Java classes should be treated as implementation details, and applications should avoid relying on them.
To look up and call a Clojure function:
IFn plus = Clojure.var("clojure.core", "+");
plus.invoke(1, 2);
Functions in clojure.core are automatically loaded. Other namespaces can be loaded via require:
IFn require = Clojure.var("clojure.core", "require");
require.invoke(Clojure.read("clojure.set"));
IFns can be passed to higher order functions, e.g. the example below passes plus to read:
IFn map = Clojure.var("clojure.core", "map");
IFn inc = Clojure.var("clojure.core", "inc");
map.invoke(inc, Clojure.read("[1 2 3]"));
Most IFns in Clojure refer to functions. A few, however, refer to non-function data values. To access these, use deref instead of fn:
IFn printLength = Clojure.var("clojure.core", "*print-length*");
Clojure.var("clojure.core", "deref").invoke(printLength);
In the past, map destructuring with :keys and :syms would not work with maps containing namespaced keys or symbols. The :keys and :syms forms have been updated to allow them to match namespaced keys and bind to a local variable based on the name.
Examples:
(let [m {:x/a 1, :y/b 2}
{:keys [x/a y/b]} m]
(+ a b))
(let [m {'x/a 1, 'y/b 2}
{:syms [x/a y/b]} m]
(+ a b))
Additionally, the :keys form can now take keywords instead of symbols. This provides support specifically for auto-resolved keywords:
(let [m {:x/a 1, :y/b 2}
{:keys [:x/a :y/b]} m]
(+ a b))
(let [m {::x 1}
{:keys [::x]} m]
x)
Many conditional functions rely on logical truth (where "falsey" values are nil or false). Sometimes it is useful to have functions that rely on "not nilness" instead. These functions have been added to support these cases [CLJ-1343]:
- some? - same as (not (nil? x))
- if-some - like if-let, but checks (some? test) instead of test
- when-some - like when-let, but checks (some? test) instead of test
Clojure 1.6 provides new hashing algorithms for primitives and collections, accessible via IHashEq/hasheq (in Java) or the clojure.core/hash function (in Clojure). In general, these changes should be transparent to users, except hash codes used inside hashed collections like maps and sets will have better properties.
Hash codes returned by the Java .hashCode() method are unchanged and continue to match Java behavior or conform to the Java specification as appropriate.
Any collections implementing IHashEq or wishing to interoperate with
Clojure collections should conform to the hashing algorithms specified
in http://clojure.org/data_structures#hash and use the new function
mix-collection-hash for the final mixing operation. Alternatively,
you may call the helper functions hash-ordered-coll and
hash-unordered-coll.
Any details of the current hashing algorithm not specified on that page should be considered subject to future change.
Related tickets for dev and regressions:
- CLJ-1328 Make several Clojure tests independent of ordering
- CLJ-1331 Update primitive vectors to use Murmur3 hash
- CLJ-1335 Update hash for empty PersistentList and LazySeq
- CLJ-1336 Make hashing mixing functions available in Clojure
- CLJ-1338 Make Murmur3 class public
- CLJ-1344 Update mapHasheq to call Murmur3 algorithm
- CLJ-1348 Add hash-ordered-coll and hash-unordered-coll
- CLJ-1355 Restore cached hashCode for Symbol and (uncached) hashCode for Keyword
- CLJ-1365 Add type hints for new collection hash functions
- CLJ-827 - unsigned-bit-shift-right
A new unsigned-bit-shift-right (Java's >>>) has been added to the core library. The shift distance is truncated to the least 6 bits (per the Java specification for long >>>).
Examples: (unsigned-bit-shift-right 2r100 1) ;; 2r010 (unsigned-bit-shift-right 2r100 2) ;; 2r001 (unsigned-bit-shift-right 2r100 3) ;; 2r000
Added a new clojure.test/test-vars function that takes a list of vars, groups them by namespace, and runs them with their fixtures.
- CLJ-908 Print metadata for functions when print-meta is true and remove errant space at beginning.
- CLJ-937 pprint cl-format now supports E, F, and G formats for ratios.
- CLJ-1248 Include type information in reflection warning messages
- CLJ-1099 If non-seq passed where seq is needed, error message now is an ExceptionInfo with the instance value, retrievable via ex-data.
- CLJ-1083 Fix error message reporting for "munged" function names (like a->b).
- CLJ-1056 Handle more cases and improve error message for errors in defprotocol definitions.
- CLJ-1102 Better handling of exceptions with empty stack traces.
- CLJ-939 Exceptions thrown in the top level ns form are reported without file or line number.
- CLJ-1164 Fix typos in clojure.instant/validated and other internal instant functions.
- CLJ-1143 Correct doc string for ns macro.
- CLJ-196 Clarify value of file is undefined in the REPL.
- CLJ-1228 Fix a number of spelling errors in namespace and doc strings.
- CLJ-835 Update defmulti doc to clarify expectations for hierarchy argument.
- CLJ-1304 Fix minor typos in documentation and comments
- CLJ-1302 Mention that keys and vals order are consistent with seq order
- CLJ-858 Improve speed of STM by removing System.currentTimeMillis.
- CLJ-669 clojure.java.io/do-copy: use java.nio for Files
- commit Reduce overhead of protocol callsites by removing unneeded generated cache fields.
- CLJ-908 Make default-data-reader-fn set!-able in REPL, similar to data-readers.
- CLJ-783 Make clojure.inspector/inspect-tree work on sets.
- CLJ-896 Make browse-url aware of xdg-open.
- CLJ-1160 Fix clojure.core.reducers/mapcat does not stop on reduced? values.
- CLJ-1121 -> and ->> have been rewritten to work with a broader set of macros.
- CLJ-1105 clojure.walk now supports records.
- CLJ-949 Removed all unnecessary cases of sneakyThrow.
- CLJ-1238 Allow EdnReader to read foo// (matches LispReader behavior).
- CLJ-1264 Remove uses of _ as a var in the Java code (causes warning in Java 8).
- CLJ-394 Add record? predicate.
- CLJ-1200 ArraySeq dead code cleanup, ArraySeq_short support added.
- CLJ-1331 Primitive vectors should implement hasheq and use new hash algorithm
- CLJ-1354 Make APersistentVector.SubVector public so other collections can access
- CLJ-1353 Make awt run headless during the build process
- CLJ-1018 Make range consistently return infinite sequence of start with a step of 0.
- CLJ-863 Make interleave return () on 0 args and identity on 1 args.
- CLJ-1072 Update internal usages of the old metadata reader syntax to new syntax.
- CLJ-1193 Make bigint and biginteger functions work on double values outside long range.
- CLJ-1154 Make Compile.java flush but not close stdout so errors can be reported.
- CLJ-1161 Remove bad version.properties from sources jar.
- CLJ-1175 Fix invalid behavior of Delay/deref if an exception is thrown - exception will now be rethrown on subsequent calls and not enter a corrupted state.
- CLJ-1171 Fix several issues with instance? to make it consistent when used with apply.
- CLJ-1202 Protocol fns with dashes may get incorrectly compiled into field accesses.
- CLJ-850 Add check to emit invokePrim with return type of double or long if type-hinted.
- CLJ-1177 clojure.java.io URL to File coercion corrupts path containing UTF-8 characters.
- CLJ-1234 Accept whitespace in Record and Type reader forms (similar to data literals).
- CLJ-1233 Allow ** as a valid symbol name without triggering dynamic warnings.
- CLJ-1246
Add support to clojure.reflect for classes with annotations.
- CLJ-1184 Evaling #{do ...} or [do ...] is treated as do special form.
- CLJ-1090 Indirect function calls through Var instances fail to clear locals.
- CLJ-1076 pprint tests fail on Windows, expecting \n.
- CLJ-766 Make into-array work consistently with short-array and byte-array on bigger types.
- CLJ-1285 Data structure invariants are violated after persistent operations when collision node created by transients.
- CLJ-1222 Multiplication overflow issues around Long/MIN_VALUE
- CLJ-1118 Inconsistent numeric comparison semantics between BigDecimals and other numerics
- CLJ-1125 Clojure can leak memory in a servlet container when using dynamic bindings or STM transactions.
- CLJ-1082 Subvecs of primitve vectors cannot be reduced
- CLJ-1301 Case expressions use a mixture of hashCode and hasheq, potentially leading to missed case matches when these differ.
- CLJ-983 proxy-super does not restore original binding if call throws exception
- CLJ-1176 clojure.repl/source errors when read-eval bound to :unknown
- CLJ-935 clojure.string/trim uses different definition of whitespace than triml and trimr
- CLJ-1058 StackOverflowError on exception in reducef for PersistentHashMap fold
- CLJ-1328 Fix some tests in the Clojure test suite to make their names unique and independent of hashing order
- CLJ-1339 Empty primitive vectors throw NPE on .equals with non-vector sequential types
- CLJ-1363 Field access via .- in reflective case does not work
- CLJ-944 Compiler gives constant collections types which mismatch their runtime values
- CLJ-1387 reduce-kv on large hash maps ignores reduced result
- fix for leak caused by ddc65a96fdb1163b
1 Deprecated and Removed Features
1.1 Clojure 1.5 reducers library requires Java 6 or later
2 New and Improved Features
2.1 Reducers
2.2 Reader Literals improved
2.3 clojure.core/set-agent-send-executor!, set-agent-send-off-executor!, and send-via
2.4 New threading macros
2.5 Column metadata captured by reader
2.6 gen-class improvements
2.7 Support added for marker protocols
2.8 clojure.pprint/print-table output compatible with Emacs Org mode
2.9 clojure.string/replace and replace-first handle special characters more predictably
2.10 Set and map constructor functions allow duplicates
2.11 More functions preserve metadata
2.12 New edn reader, improvements to *read-eval*
3 Performance Enhancements
4 Improved error messages
5 Improved documentation strings
6 Bug Fixes
7 Binary Compatibility Notes
The new reducers library (see below) requires Java 6 plus a ForkJoin library, or Java 7 or later. Clojure 1.5 can still be compiled and run with Java 5. The only limitations with Java 5 are that the new reducers library will not work, and building Clojure requires skipping the test suite (e.g. by using the command "ant jar").
Reducers provide a set of high performance functions for working with collections. The actual fold/reduce algorithms are specified via the collection being reduced. This allows each collection to define the most efficient way to reduce its contents.
The implementation details of reducers are available at the Clojure blog and therefore won't be repeated in these change notes. However, as a summary:
- There is a new namespace: clojure.core.reducers
- It contains new versions of map, filter etc based upon transforming reducing functions - reducers
- It contains a new function, fold, which is a parallel reduce+combine fold uses fork/join when working with (the existing!) Clojure vectors and maps
- Your new parallel code has exactly the same shape as your existing seq-based code
- The reducers are composable
- Reducer implementations are primarily functional - no iterators
- The model uses regular data structures, not 'parallel collections' or other OO malarkey
- It's fast, and can become faster still
- This is work-in-progress
Examples:
user=> (require '[clojure.core.reducers :as r])
user=> (reduce + (r/filter even? (r/map inc [1 1 1 2])))
;=> 6
;;red is a reducer awaiting a collection
user=> (def red (comp (r/filter even?) (r/map inc)))
user=> (reduce + (red [1 1 1 2]))
;=> 6
user=> (into #{} (r/filter even? (r/map inc [1 1 1 2])))
;=> #{2}
-
CLJ-1034 "Conflicting data-reader mapping" should no longer be thrown where there really isn't a conflict. Until this patch, having data_readers.clj on the classpath twice would cause the above exception.
-
CLJ-927 Added
*default-data-reader-fn*to clojure.core. When no data reader is found for a tag and*default-data-reader-fn*is non-nil, it will be called with two arguments, the tag and the value. If*default-data-reader-fn*is nil (the default), an exception will be thrown for the unknown tag.
Added two new functions:
-
clojure.core/set-agent-send-executor!
Allows the user to set the
java.util.concurrent.Executorused when callingclojure.core/send. Defaults to a fixed thread pool of size: (numCores + 2) -
clojure.core/set-agent-send-off-executor!
Allows the user to set the
java.util.concurrent.Executorused when callingclojure.core/send-off. Defaults to a cached thread pool. -
clojure.core/send-via
Like
send, andsend-off, except the first argument to this function is an executor to use when sending.
-
clojure.core/cond-> [expr & clauses]
Takes an expression and a set of test/form pairs. Threads the expression (via ->) through each form for which the corresponding test expression (not threaded) is true.
Example:
user=> (cond-> 1
true inc
false (* 42)
(= 2 2) (* 3))
6
-
clojure.core/cond->> [expr & clauses]
Takes an expression and a set of test/form pairs. Threads expr (via ->>) through each form for which the corresponding test expression (not threaded) is true.
Example:
user=> (def d [0 1 2 3])
#'user/d
user=> (cond->> d
true (map inc)
(seq? d) (map dec)
(= (count d) 4) (reduce +)) ;; no threading in the test expr
;; so d must be passed in explicitly
10
- clojure.core/as-> [expr name & forms]
Binds name to expr, evaluates the first form in the lexical context of that binding, then binds name to that result, repeating for each successive form
Note: this form does not actually perform any threading. Instead it allows the user to assign a name and lexical context to a value created by a parent threading form.
Example:
user=> (-> 84
(/ 4)
(as-> twenty-one ;; uses the value from ->
(* 2 twenty-one))) ;; no threading here
42
- clojure.core/some-> [expr & forms]
When expr is not nil, threads it into the first form (via ->), and when that result is not nil, through the next etc.
Example:
user=> (defn die [x] (assert false))
#'user/die
user=> (-> 1 inc range next next next die)
AssertionError Assert failed: false user/die (NO_SOURCE_FILE:65)
user=> (some-> 1 inc range next next next die)
nil
-
clojure.core/some->> [expr & forms]
When expr is not nil, threads it into the first form (via ->>), and when that result is not nil, through the next etc.
Same as some-> except the value is threaded as the last argument in each form.
- CLJ-960 Data read by the clojure reader is now tagged with :column in addition to :line.
- CLJ-745
It is now possible to expose protected final methods via
:exposes-methodsingen-class. This allows Clojure classes created via gen-class to access protected methods of its parent class.
Example:
(gen-class :name clojure.test_clojure.genclass.examples.ProtectedFinalTester
:extends java.lang.ClassLoader
:main false
:prefix "pf-"
:exposes-methods {findSystemClass superFindSystemClass})
- CLJ-948
It is now possible to annotate constructors via
gen-class.
Example:
(gen-class :name foo.Bar
:extends clojure.lang.Box
:constructors {^{Deprecated true} [Object] [Object]}
:init init
:prefix "foo")
- CLJ-966
defprotocolno longer requires that at least one method be given in the definition of the protocol. This allows for marker protocols, whose sole reason of existence is to allowsatisfies?to be true for a given type.
Example:
user=> (defprotocol P (hi [_]))
P
user=> (defprotocol M) ; marker protocol
M
user=> (deftype T [a] M P (hi [_] "hi there"))
user.T
user=> (satisfies? P (T. 1))
true
user=> (satisfies? M (T. 1))
true
user=> (hi (T. 1))
"hi there"
user=> (defprotocol M2 "marker for 2") ; marker protocol again
M2
user=> (extend-type T M2)
nil
user=> (satisfies? M2 (T. 1))
true
For the convenience of those that use Emacs Org mode,
clojure.pprint/print-table now prints tables in the form used by
that mode. Emacs Org mode has features to make it easy to edit such
tables, and even to do spreadsheet-like calculations on their
contents. See the Org mode documentation on
tables for details.
user=> (clojure.pprint/print-table [:name :initial-impression]
[{:name "Rich" :initial-impression "rock star"}
{:name "Andy" :initial-impression "engineer"}])
| :name | :initial-impression |
|-------+---------------------|
| Rich | rock star |
| Andy | engineer |
clojure.string/replace and clojure.string/replace-first are now
consistent in the way that they handle the replacement strings: all
characters in the replacement strings are treated literally, including
backslash and dollar sign characters.
user=> (require '[clojure.string :as s])
user=> (s/replace-first "munge.this" "." "$")
;=> "munge$this"
user=> (s/replace "/my/home/dir" #"/" (fn [s] "\\"))
;=> "\\my\\home\\dir"
There is one exception, which is described in the doc strings. If you
call these functions with a regex to search for and a string as the
replacement, then dollar sign and backslash characters in the
replacement string are treated specially. Occurrences of $1 in the
replacement string are replaced with the string that matched the first
parenthesized subexpression of the regex, occurrences of $2 are
replaced with the match of the second parenthesized subexpression,
etc.
user=> (s/replace "x12, b4" #"([a-z]+)([0-9]+)" "$1 <- $2")
;=> "x <- 12, b <- 4"
Individual occurrences of $ or \ in the replacement string that
you wish to be treated literally can be escaped by prefixing them with
a \. If you wish your replacement string to be treated literally
and its contents are unknown to you at compile time (or you don't wish
to tarnish your constant string with lots of backslashes), you can use
the new function clojure.string/re-quote-replacement to do the
necessary escaping of special characters for you.
user=> (s/replace "x12, b4" #"([a-z]+)([0-9]+)"
(s/re-quote-replacement "$1 <- $2"))
;=> "$1 <- $2, $1 <- $2"
All of the functions that construct sets such as set and
sorted-set allow duplicate elements to appear in their arguments,
and they are documented to treat this case as if by repeated uses of
conj.
Similarly, all map constructor functions such as hash-map,
array-map, and sorted-map allow duplicate keys, and are documented
to treat this case as if by repeated uses of assoc.
As before, literal sets, e.g. #{1 2 3}, do not allow duplicate
elements, and while elements can be expressions evaluated at run time
such as #{(inc x) (dec y)}, this leads to a check for duplicates at
run time whenever the set needs to be constructed, throwing an
exception if any duplicates are found.
Similarly, literal maps do not allow duplicate keys. New to Clojure 1.5 is a performance optimization: if all keys are compile time constants but one or more values are expressions requiring evaluation at run time, duplicate keys are checked for once at compile time only, not each time a map is constructed at run time.
- CLJ-1065 Allow duplicate set elements and map keys for all set and map constructors
Most functions that take a collection and return a "modified" version
of that collection preserve the metadata that was on the input
collection, e.g. conj, assoc, dissoc, etc. One notable
exception was into, which would return a collection with metadata
nil for several common types of input collections.
Now the functions into, select-keys, clojure.set/project, and
clojure.set/rename return collections with the same metadata as
their input collections.
The new clojure.edn namespace reads edn (http://edn-format.org) data,
and should be used for reading data from untrusted sources.
Clojure's core read* functions can evaluate code, and should not be
used to read data from untrusted sources. As of 1.5, *read-eval*
supports a documented set of thread-local bindings, see the doc string
for details.
*read-eval*'s default can be set to false by setting a system property:
-Dclojure.read.eval=false
- CLJ-988 Multimethod tables are now protected by a read/write lock instead of a synchronized method. This should result in a performance boost for multithreaded code using multimethods.
- CLJ-1061
when-firstnow evaluates its expression only once. - CLJ-1084
PersistentVector$ChunkedSeqnow implementsCountedinterface, to avoid some cases where vector elements were being counted by iterating over their elements. - CLJ-867 Records with same fields and field values, but different types, now usually hash to different values.
- CLJ-1000 Cache hasheq() for seqs, sets, vectors, maps and queues
- (no ticket) array-map perf tweaks
- CLJ-1111 Allows loop to evaluate to primitive values
- (no ticket) Move loop locals into same clearing context as loop body
- CLJ-103 Improved if-let error message when form has a improperly defined body.
- CLJ-897 Don't use destructuring in defrecord/deftype arglists to get a slightly better error message when forgetting to specify the fields vector
- CLJ-788 Add source and line members and getters to CompilerException
- CLJ-157 Better error messages for syntax errors w/ defn and fn
- CLJ-940 Passing a non-sequence to refer :only results in uninformative exception
- CLJ-1052
assocnow throws an exception if the last key argument is missing a value.
- CLJ-893 Document that vec will alias Java arrays
- CLJ-892 Clarify doc strings of sort and sort-by: they will modify Java array arguments
- CLJ-1019 ns-resolve doc has a typo
- CLJ-1038 Docstring for deliver doesn't match behavior
- CLJ-1055 "be come" should be "become"
- CLJ-917 clojure.core/definterface is not included in the API docs
- (no ticket) clojure.core/read, read-string, and read-eval all have more extensive documentation.
- CLJ-962 Vectors returned by subvec allow access at negative indices
- CLJ-952 bigdec does not properly convert a clojure.lang.BigInt
- CLJ-975 inconsistent destructuring behaviour when using nested maps
- CLJ-954 TAP support in clojure.test.tap Needs Updating
- CLJ-881 exception when cl-format is given some ~f directive/value combinations
- CLJ-763 Do not check for duplicates in destructuring map creation
- CLJ-667 Allow loops fully nested in catch/finally
- CLJ-768 cl-format bug in ~f formatting
- CLJ-844 NPE calling keyword on map from bean
- CLJ-934 disj! Throws exception when attempting to remove multiple items in one call
- CLJ-943 When load-lib fails, a namespace is still created
- CLJ-981 clojure.set/rename-keys deletes keys when there's a collision
- CLJ-961 with-redefs loses a Var's root binding if the Var is thread-bound
- CLJ-1032 seque leaks threads from the send-off pool
- CLJ-1041 reduce-kv on sorted maps should stop on seeing a Reduced value
- CLJ-1011 clojure.data/diff should cope with null and false values in maps
- CLJ-977 (int \a) returns a value, (long \a) throws an exception
- CLJ-964 test-clojure/rt.clj has undeclared dependency on clojure.set
- CLJ-923 Reading ratios prefixed by + is not working
- CLJ-1012 partial function should also accept 1 arg (just f)
- CLJ-932 contains? Should throw exception on non-keyed collections
- CLJ-730 Create test suite for functional fns (e.g. juxt, comp, partial, etc.)
- CLJ-757 Empty transient maps/sets return wrong value for .contains
- CLJ-828 clojure.core/bases returns a cons when passed a class and a Java array when passed an interface
- CLJ-1062 CLJ-940 breaks compilation of namespaces that don't have any public functions
- CLJ-1070 PersistentQueue's hash function does not match its equality
- CLJ-987 pprint doesn't flush the underlying stream
- CLJ-963 Support pretty printing namespace declarations under code-dispatch
- CLJ-902 doc macro broken for namespaces
- CLJ-909 Make LineNumberingPushbackReader's buffer size configurable
- CLJ-910 Allow for type-hinting the method receiver in memfn
- CLJ-1048 add test.generative to Clojure's tests
- CLJ-1071 ExceptionInfo does no abstraction
- CLJ-1085 clojure.main/repl unconditionally refers REPL utilities into
*ns* - (no ticket) Rich Hickey fix: syntax-quote was walking records, returning maps
- CLJ-1116 More REPL-friendly 'ns macro
- (no ticket) Rich Hickey fix: deref any j.u.c.Future
- CLJ-1092 New function re-quote-replacement has incorrect :added metadata
- CLJ-1098 Implement IKVReduce and CollFold for nil
- (no ticket) Rich Hickey fix: impose once semantics on fabricated closures for e.g. loops
- CLJ-1140 Restore {:as x} destructuring for empty lists
- CLJ-1150 Make some PersistentVector's and APersistentVector.SubVector's internals public
- (no ticket) Rich Hickey fix: use non-loading classForName
- CLJ-1106 Fixing set equality
public static inner class LispReader.ReaderException(int line, Throwable cause)Constructor changed toReaderException(int line, int column, Throwable cause)public Object clojure.lang.Agent.dispatch(IFn fn, ISeq args, boolean solo)Replaced withdispatch(IFn fn, ISeq args, Executor exec)
1 Deprecated and Removed Features
1.1 Fields that Start With a Dash Can No Longer Be Accessed Using Dot Syntax
2 New/Improved Features
2.1 Reader Literals
2.2 clojure.core/mapv
2.3 clojure.core/filterv
2.4 clojure.core/ex-info and clojure.core/ex-data
2.5 clojure.core/reduce-kv
2.6 clojure.core/contains? Improved
2.7 clojure.core/min and clojure.core/max prefer NaN
2.8 clojure.java.io/as-file and clojure.java.io/as-url Handle URL-Escaping Better
2.9 New Dot Syntax for Record and Type Field Access
2.10 Record Factory Methods Available Inside defrecord
2.11 assert-args Displays Namespace and Line Number on Errors
2.12 File and Line Number Added to Earmuff Dynamic Warning
2.13 require Can Take a :refer Option
2.14 *compiler-options* Var
2.15 Improved Reporting of Invalid Characters in Unicode String Literals
2.16 clojure.core/hash No Longer Relies on .hashCode
2.17 Java 7 Documentation
2.18 loadLibrary Loads Library Using System ClassLoader
2.19 Java int is boxed as java.lang.Integer
3 Performance Enhancements
4 Bug Fixes
Clojure 1.4 introduces a field accessor syntax for the dot special form that aligns Clojure field lookup syntax with ClojureScript's.
For example, in Clojure 1.3, one can declare a record with a field starting with dash and access it like this:
(defrecord Bar [-a]) ;=> user.Bar
(.-a (Bar. 10)) ;=> 10
In 1.4, the above code results in IllegalArgumentException No matching field found: a for class user.Bar
However, the field may still be accessed as a keyword:
(:-a (Bar. 10)) ;=> 10
Clojure 1.4 supports reader literals, which are data structures tagged by a symbol to denote how they will be read.
When Clojure starts, it searches for files named data_readers.clj
at the root of the classpath. Each such file must contain a Clojure
map of symbols, like this:
{foo/bar my.project.foo/bar
foo/baz my.project/baz}
The key in each pair is a tag that will be recognized by the Clojure reader. The value in the pair is the fully-qualified name of a Var which will be invoked by the reader to parse the form following the tag. For example, given the data_readers.clj file above, the Clojure reader would parse this form:
#foo/bar [1 2 3]
by invoking the Var #'my.project.foo/bar on the vector [1 2 3]. The
data reader function is invoked on the form AFTER it has been read
as a normal Clojure data structure by the reader.
Reader tags without namespace qualifiers are reserved for Clojure. Default
reader tags are defined in clojure.core/default-data-readers but may be
overridden in data_readers.clj or by rebinding *data-readers*.
Clojure supports literals for instants in the form
#inst "yyyy-mm-ddThh:mm:ss.fff+hh:mm". These literals are parsed as java.util.Dates
by default. They can be parsed as java.util.Calendars or java.util.Timestamps
by binding *data-readers* to use clojure.instant/read-instant-calendar or
clojure.instant/read-instant-timestamp.
(def instant "#inst \"@2010-11-12T13:14:15.666\"")
; Instants are read as java.util.Date by default
(= java.util.Date (class (read-string instant)))
;=> true
; Instants can be read as java.util.Calendar or java.util.Timestamp
(binding [*data-readers* {'inst read-instant-calendar}]
(= java.util.Calendar (class (read-string instant))))
;=> true
(binding [*data-readers* {'inst read-instant-timestamp}]
(= java.util.Timestamp (class (read-string instant))))
;=> true
Clojure supports literals for UUIDs in the form #uuid "uuid-string". These
literals are parsed as java.util.UUIDs.
mapv takes a function f and one or more collections and returns a
vector consisting of the result of applying f to the set of first items of
each collection, followed by applying f to the set of second items in each
collection, until any one of the collections is exhausted. Any remaining
items in other collections are ignored. f should accept a number of arguments
equal to the number of collections.
(= [1 2 3] (mapv + [1 2 3]))
;=> true
(= [2 3 4] (mapv + [1 2 3] (repeat 1)))
;=> true
filterv takes a predicate pred and a collection and returns a vector
of the items in the collection for which (pred item) returns true. pred
must be free of side-effects.
(= [] (filterv even? [1 3 5]))
;=> true
(= [2 4] (filterv even? [1 2 3 4 5]))
;=> true
ex-info creates an instance of ExceptionInfo. ExceptionInfo is a
RuntimeException subclass that takes a string msg and a map of data.
(ex-info "Invalid use of robots" {:robots false})
;=> #<ExceptionInfo clojure.lang.ExceptionInfo: Invalid use of robots {:robots false}>
ex-data is called with an exception and will retrieve that map of data
if the exception is an instance of ExceptionInfo.
(ex-data (ex-info "Invalid use of robots" {:robots false}))
;=> {:robots false}
reduce-kv reduces an associative collection. It takes a function f,
an initial value init and an associative collection coll. f should
be a function of 3 arguments. Returns the result of applying f to init,
the first key and the first value in coll, then applying f to that result
and the 2nd key and value, etc. If coll contains no entries, returns init
and f is not called. Note that reduce-kv is supported on vectors,
where the keys will be the ordinals.
(reduce-kv str "Hello " {:w \o :r \l :d \!})
;=> "Hello :rl:d!:wo"
(reduce-kv str "Hello " [\w \o \r \l \d \!])
;=> "Hello 0w1o2r3l4d5!"
contains? now works with java.util.Set.
min and max now give preference to returning NaN if either of their
arguments is NaN.
as-file and as-url now handle URL-escaping in both directions.
Clojure 1.4 introduces a field accessor syntax for the dot special form that aligns Clojure field lookup syntax with ClojureScript's.
In 1.4, to declare a record type and access its property x, one can
write:
(defrecord Foo [x]) ;=> user.Foo
(.-x (Foo. 10)) ;=> 10
This addition makes it easier to write code that will run as expected in both Clojure and ClojureScript.
Prior to 1.4, you could not use the factory functions (->RecordClass
and map->RecordClass) to construct a new record from inside a
defrecord definition.
The following example did not work prior to 1.4, but is now
valid. This example makes use of ->Mean which would have not yet
been available.
(defrecord Mean [last-winner]
Player
(choose [_] (if last-winner last-winner (random-choice)))
(update-strategy [_ me you] (->Mean (when (iwon? me you) me))))
assert-args now uses &form to report the namespace and line number where
macro syntax errors occur.
When a variable is defined using earmuffs but is not declared dynamic, Clojure emits a warning. That warning now includes the file and line number.
require can now take a :refer option. :refer takes a list of symbols
to refer from the namespace or :all to bring in all public vars.
The dynamic var *compiler-options* contains a map of options to send
to the Clojure compiler.
Supported options:
:elide-meta: Have certain metadata elided during compilation. This should be set to a collection of keywords.:disable-locals-clearing: Set to true to disable clearing. Useful for using a debugger.
The main function of the Clojure compiler sets the
*compiler-options* from properties prefixed by clojure.compiler,
e.g.
java -Dclojure.compiler.elide-meta='[:doc :file :line]'
When the reader finds an invalid character in a Unicode string literal, it now reports the character instead of its numerical representation.
hash no longer directly uses .hashCode() to return the hash of a Clojure
data structure. It calls clojure.lang.Util.hasheq, which has its own implementation
for Integer, Short, Byte, and Clojure collections. This ensures that the hash code
returned is consistent with =.
*core-java-api* will now return the URL for the Java 7 Javadoc when you are
running Java 7.
A static method, loadLibrary, was added to clojure.lang.RT to load a
library using the system ClassLoader instead of Clojure's class loader.
Java ints are now boxed as java.lang.Integers. See
the discussion on clojure-dev
for more information.
(= char char)is now optimizedequivis inlined in variadic =toStringcached on keywords and symbols
- CLJ-829 Transient hashmaps mishandle hash collisions
- CLJ-773 Macros that are expanded away still have their vars referenced in the emitted byte code
- CLJ-837 java.lang.VerifyError when compiling deftype or defrecord with argument name starting with double underscore characters
- CLJ-369 Check for invalid interface method names
- CLJ-845
Unexpected interaction between protocol extension and namespaced method keyword/symbols
- Ignoring namespace portion of symbols used to name methods in extend-type and extend-protocol
- CLJ-852 IllegalArgumentException thrown when defining a var whose value is calculated with a primitive fn
- CLJ-855 catch receives a RuntimeException rather than the expected checked exception
- CLJ-876 #^:dynamic vars declared in a nested form are not immediately dynamic
- CLJ-886 java.io/do-copy can garble multibyte characters
- CLJ-895
Collection.toArray implementations do not conform to Java API docs
- obey contract for toArray return type
- CLJ-898
Agent sends consume heap
- Only capture a shallow copy of the current Frame in binding-conveyor-fn, so that sends in agent actions don't build infinite Frame stacks
- CLJ-928 Instant literal for Date and Timestamp should print in UTC
- CLJ-931 Syntactically broken clojure.test/are tests succeed
- CLJ-933 Compiler warning on clojure.test-clojure.require-scratch
1 Deprecated and Removed Features
1.1 Earmuffed Vars are No Longer Automatically Considered Dynamic
1.2 ISeq No Longer Inherits from Sequential
1.3 Removed Bit Operation Support for Boxed Numbers
1.4 Ancillary Namespaces No Longer Auto-Load on Startup
1.5 Replicate Deprecated
2 New/Improved Features
2.1 Enhanced Primitive Support
2.2 defrecord and deftype Improvements
2.3 Better Exception Reporting
2.4 clojure.reflect/reflect
2.5 clojure.data/diff
2.6 clojure.core/every-pred and clojure.core/some-fn Combinators
2.7 clojure.core/realized?
2.8 clojure.core/with-redefs-fn & with-redefs
2.9 clojure.core/find-keyword
2.10 clojure.repl/pst
2.11 clojure.pprint/print-table
2.12 pprint respects *print-length*
2.13 compilation and deployment via Maven
2.14 internal keyword map uses weak refs
2.15 ^:const defs
2.16 Message Bearing Assert
2.17 Error Checking for defmulti Options
2.18 Removed Checked Exceptions
2.19 vector-of Takes Multiple Arguments
2.20 deref with timeout
2.21 Walk Support for sorted-by Collections
2.22 string.join Enhanced to Work with Sets
2.23 clojure.test-helper
2.24 Newline outputs platform-specific newline sequence
2.25 init-proxy and update-proxy return proxy
2.26 doc & find-doc moved to REPL
2.27 clojure.java.shell/sh accepts as input anything that clojure.java.io/copy does
2.28 InterruptedHandler Promoted to clojure.repl
2.29 Add support for running -main namespaces from clojure.main
2.30 Set thread names on agent thread pools
2.31 Add docstring support to def
2.32 Comp function returns identity when called with zero arity
2.33 Type hints can be applied to arg vectors
2.34 Binding Conveyance
3 Performance Enhancements
4 Bug Fixes
5 Modular Contrib
(def *fred*)
=> Warning: *fred* not declared dynamic and thus is not dynamically rebindable, but its name suggests otherwise. Please either indicate ^:dynamic ** or change the name.
This allows ISeq implementers to be in the map or set equality partition.
Bit Operations map directly to primitive operations
The following namespaces are no longer loaded on startup: clojure.set, clojure.xml, clojure.zip
Use repeat instead.
Full details here:
Details here: Defrecord Improvements
Details here: Error Handling
Additionally:
Better error messages:
- When calling macros with arity
- For Invalid Map Literals
- For alias function if using unknown namespace
- In the REPL
- Add "starting at " to EOF while reading exceptions
- Better compilation error reporting
Full details here: Reflection API
Recursively compares a and b, returning a tuple of [things-only-in-a things-only-in-b things-in-both]
(diff {:a 1 :b 2} {:a 1 :b 22 :c 3})
=> ({:b 2} {:c 3, :b 22} {:a 1})
every-pred takes a set of predicates and returns a function f that returns true if all of its composing predicates return a logical true value against all of its arguments, else it returns false.
((every-pred even?) 2 4 6)
=> true
((every-pred even?) 2 4 5)
=>false
some-fn takes a set of predicates and returns a function f that returns the first logical true value returned by one of its composing predicates against any of its arguments, else it returns logical false.
((some-fn even?) 2 4 5)
=> true
((some-fn odd?) 2 4 6)
=> false
Returns true if a value has been produced for a promise, delay, future or lazy sequence.
(let [x (range 5)]
(println (realized? x))
(first x)
(println (realized? x)))
=> false
=> true
with-redefs-fn temporarily redefines Vars during a call to func. with-redefs temporarily redefines Vars while executing the body.
(with-redefs [nil? :temp] (println nil?))
=> :temp
Returns a Keyword with the given namespace and name if one already exists.
(find-keyword "def")
=> :def
(find-keyword "fred")
=> nil
Prints a stack trace of the exception
(pst (IllegalArgumentException.))
IllegalArgumentException
user/eval27 (NO_SOURCE_FILE:18)
clojure.lang.Compiler.eval (Compiler.java:6355)
clojure.lang.Compiler.eval (Compiler.java:6322)
clojure.core/eval (core.clj:2699)
clojure.main/repl/read-eval-print--5906 (main.clj:244)
clojure.main/repl/fn--5911 (main.clj:265)
clojure.main/repl (main.clj:265)
clojure.main/repl-opt (main.clj:331)
clojure.main/main (main.clj:427)
clojure.lang.Var.invoke (Var.java:397)
clojure.lang.Var.applyTo (Var.java:518)
clojure.main.main (main.java:37)
Prints a collection of maps in a textual table.
(print-table [:fred :barney]
[{:fred "ethel"}
{:fred "wilma" :barney "betty"}])
===============
:fred | :barney
===============
ethel |
wilma | betty
===============
Assigning *print-length* now affects output of pprint
See the following pages for more information:
^:const lets you name primitive values with speedier reference.
(def constants
{:pi 3.14
:e 2.71})
(def ^:const pi (:pi constants))
(def ^:const e (:e constants))
The overhead of looking up :e and :pi in the map happens at compile time, as (:pi constants) and (:e constants) are evaluated when their parent def forms are evaluated.
Assert can take a second argument which will be printed when the assert fails
(assert (= 1 2) "1 is not equal to 2")
=> AssertionError Assert failed: 1 is not equal to 2
defmulti will check to verify that its options are valid. For example, the following code will throw an exception:
(defmulti fred :ethel :lucy :ricky)
=> IllegalArgumentException
Clojure does not throw checked exceptions
vector-of takes multiple args used to populate the array
(vector-of :int 1 2 3)
=> [1 2 3]
deref now takes a timeout option - when given with a blocking reference, will return the timeout-val if the timeout (in milliseconds) is reached before value is available.
(deref (promise) 10 :ethel)
=> :ethel
Walk modified to work on sorted-by collections
let [x (sorted-set-by > 1 2 3)] (walk inc reverse x))
=> (2 3 4)
Just like join works on other collections
(join " and " #{:fred :ethel :lucy})
=> ":lucy and :fred and :ethel"
All test helpers moved into clojure.test-helper
Newline sequence is output as \r\n on Windows now.
Now you can chain calls on the proxy
Adds special form docs to the REPL
This adds InputStream, Reader, File, byte[] to the list of inputs for clojure.java.shell/sh
Promoting this library eliminates the need for a dependency on old contrib.
This patch allows clojure.main to accept an argument pointing to a namespace to look for a -main function in. This allows users to write -main functions that will work the same whether the code is AOT-compiled for use in an executable jar or just run from source.
It's a best practice to name the threads in an executor thread pool with a custom ThreadFactory so that the purpose of these threads is clear in thread dumps and other runtime operational tools.
Patch causes thread names like:
clojure-agent-send-pool-%d (should be fixed # of threads)
clojure-agent-send-off-pool-%d (will be added and removed over time)
A def can now have a docstring between name and value.
(def foo "a foo" :foo)
(= (comp) identity)
=> true
You can hint different arities separately:
(defn hinted
(^String [])
(^Integer [a])
(^java.util.List [a & args]))
This is preferred over hinting the function name. Hinting the function name is still allowed for backward compatibility, but will likely be deprecated in a future release.
Clojure APIs that pass work off to other threads (e.g. send, send-off, pmap, future) now convey the dynamic bindings of the calling thread:
(def ^:dynamic *num* 1)
(binding [*num* 2] (future (println *num*)))
;; prints "2", not "1"
- Code path for using vars is now much faster for the common case
- Improved startup time
- Fix performance on some numeric overloads See CLJ-380 for more information
- Promises are lock free
- Functions only get metadata support code when metadata explicitly supplied
- definterface/gen-interface accepts array type hints
- inline nil?
- inline bit-functions & math ops
- inline n-ary min & max
- PersistentQueue count is now O(1)
- Intrinsics: unchecked math operators now emit bytecodes directly where possible
Complete list of Tickets for 1.3 Release.
-
CLJ-8 detect and report cyclic load dependencies
- Patch restore detection of cyclic load dependencies
-
CLJ-31 compiler now correctly rejects attempts to recur across try (fn [x] (try (recur 1))) => CompilerException
-
CLJ-286 *out* being used as java.io.PrintWriter
- Patch fixes using Writer instead of PrintWriter
- fix clojure.main to not assume that err is a PrintWriter
-
CLJ-292 LazySeq.sval() nests RuntimeExceptions
- Patch causes only the original RuntimeException to be thrown
-
CLJ-390 sends from agent error-handlers should be allowed
- Patch allows agent error-handler to send successfully
-
CLJ-426 case should handle hash collision
- There were situations where a hash collision would occur with case and an exception would be thrown. See discussion for more details
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CLJ-430 clojure.java.io URL Coercion throws java.lang.ClassCastException
- Patch correct exception to be thrown
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CLJ-432 deftype does not work if containing ns contains dashes
- Patch munges namespaces with dashes properly
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CLJ-433 munge should not munge $ (which isJavaIdentifierPart), should munge ' (which is not)
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CLJ-435 stackoverflow exception in printing meta with :type
- Patch fixes exception being thrown on certain type metadata (with-meta {:value 2} {:type Object}) => No message. [Thrown class java.lang.StackOverflowError]
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CLJ-437 Bugs in clojure.set/subset? and superset? for sets with false/nil elements
- Patch fixes failing on subset? and superset? for sets with false/nil elements
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CLJ-439 Automatic type translation from Integer to Long
- Patch fixes increase coercion from Integer to Long
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CLJ-444 Infinite recursion in Keyword.intern leads to stack overflow
- No more infinite recursion with patch
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CLJ-673 use system class loader when base loader is null
- facilitates placing Clojure on bootclasspath
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CLJ-678 into-array should work with all primitive types
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CLJ-680 printing promises should not block
- Patch allows printing of promises without blocking
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CLJ-682 cl-format: ~w throws an exception when not wrapped in a pretty-writer
- Patch fixes the following bug in cl-format with ~w:
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CLJ-693 VerifyError with symbol metadata, macros, and defrecord
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CLJ-702 case gives NPE when used with nil
- Patch allows nil to be used with case
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CLJ-734 starting scope of let bindings seems incorrect from jdi perspective
- Patch fixes local variables table to have the correct code index for let bindings.
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CLJ-739 version.properties file is not closed
- Patch properly closes version.properties file
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CLJ-751 cl-format: ~( throws an exception with an empty string
- Patch fixes the following bug in cl-format when format is nil
(cl-format nil "~:(
a)" "") => NullPointerException
- Patch fixes the following bug in cl-format when format is nil
(cl-format nil "~:(
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CLJ-780 race condition in reference cache on Java 5
- Map.Entry instances can have null values prior to Java 6. This patch provides a workaround.
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floats were being boxed as Doubles, now they are boxed as Floats
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several "holding onto head" fixes
- Stop top-level defs from hanging onto the head of an expression that uses a lazy seq
- Stop multimethods from holding onto heads of their arguments
In 1.3, the monolithic clojure-contrib.jar has been replaced by a modular system of contrib libraries, so that production systems can include only the code they actually need. This also allows individual contribs to have their own release cycles. Many contribs have moved forward by several point versions already. Documentation for updating applications to use the new contrib libraries is at http://dev.clojure.org/display/design/Where+Did+Clojure.Contrib+Go
Important Note: Many of the new modular contribs are compatible with both 1.2 and 1.3. This offers an incremental migration path: First, upgrade your contrib libraries while holding Clojure at 1.2, Then, in a separate step, upgrade to Clojure 1.3.