After a full year in development, and with more than
1500 issues closed, Ceylon 1.2.0 brings new
language features, including:
- named constructors,
- serialization,
-
native declarations,
- improved flow-sensitive typing,
- destructuring for tuples and entries
-
let, switch, if, and object expressions, and
- more powerful annotation constraints.
Furthermore, the typechecker and JavaScript backend now
support type functions as an experimental feature.
Also part of this release are enhancements to the tooling,
such as:
- a new debugger for Ceylon, and
- the Java EE packaging command,
ceylon war.
As always, this release incorporates hundreds of other
bugfixes and enhancements.
About Ceylon
Ceylon is a modern, modular, statically typed programming
language for the Java and JavaScript virtual machines. The
language features a flexible and very readable syntax, a
unique and uncommonly elegant static type system, a powerful
module architecture, and excellent tooling, including an
awesome Eclipse-based IDE.
Ceylon enables the development of cross-platform modules
that execute portably in both virtual machine environments.
Alternatively, a Ceylon module may target one or the other
platform, in which case it may interoperate with native code
written for that platform.
In the box
This release includes:
- a complete language specification that defines the
syntax and semantics of Ceylon in language accessible to
the professional developer,
- a command line toolset including compilers for
Java and JavaScript, a documentation compiler, a test
runner, a WAR archive packager, and support for executing
modular programs on the JVM and Node.js,
- a powerful module architecture for code organization,
dependency management, and module isolation at runtime,
- the language module, our minimal,
cross-platform foundation of the Ceylon SDK, and
- a full-featured Eclipse-based integrated
development environment.
Language
Ceylon is a highly understandable object-oriented language
with static typing. The language features:
- an emphasis upon readability and a strong bias toward
omission or elimination of potentially-harmful or
potentially-ambiguous constructs and toward highly
disciplined use of static types,
- an extremely powerful and uncommonly elegant type system
combining subtype and parametric polymorphism with:
- first-class union and intersection types,
- both declaration-site and use-site variance, and
- the use of principal types for local type inference
and flow-sensitive typing,
- a unique treatment of function and tuple types,
enabling powerful abstractions, along with the most
elegant approach to
null of any modern language,
- first-class constructs for defining modules and
dependencies between modules,
- a very flexible syntax including comprehensions and
support for expressing tree-like structures,
-
fully-reified generic types, on both the JVM and
JavaScript virtual machines, and a unique typesafe
metamodel.
More information about these language features may be
found in the feature list and
quick introduction.
This release introduces the following new language features
and improvements:
- named constructors,
- support for serialization libraries in the metamodel,
- the
native annotation, which allows the use of
platform-dependent code in cross-platform modules
- improvements to flow-sensitive typing,
-
destructuring for tuples and entries,
-
let, switch, and if expressions,
- inline
object expressions,
- more powerful annotation constraints,
- type argument inference for function references,
- an improved algorithm for type argument inference in
invocation expressions,
- improvements to analysis of disjointness for sequence
types,
- new type abbreviations,
T[N] and T(*A),
- an abbreviated syntax for identifying the containing
`package`, `module`, `class`, or
`interface`,
- inline variable defininition in
switch
- the ability to directly
import members of a singleton
object,
-
relaxation of type constraint checking where
unnecessary to ensure soundness, and
- experimental support for type functions (higher-order
generics) and references to generic functions (higher-rank
polymorphism).
Language module
For Ceylon 1.2, the following new APIs were introduced to
the language module:
- the
map() and set() functions allow creation of
immutable Maps and Sets with no dependency to
ceylon.collection,
-
distinct, frequences(), group(), tabulate(), and
summarize() were added to Iterable,
-
getOrDefault(), defaultNullItems(), and coalescedMap
were added to Map,
-
Collection.permutations() was added,
-
formatFloat() was added,
- the
Contextual interface was added, a cross-platform
abstraction of thread-local values,
- some operations of
List were split out onto the new
SearchableList interface, and
-
arrayOfSize() was deperecated and replaced with the
constructor Array.ofSize().
Furthermore, some native implementation code has been
rewritten in Ceylon using native.
Enhancements to the Java compiler include:
- much improved interoperation with Maven, including support
for overriding module metadata with
overrides.xml, and
--flat-classpath and --auto-export-maven-dependencies,
- all compiled classes are now
Serializable and have
default constructors, allowing much smoother
interoperation with certain Java frameworks,
- improved interoperation with Java annotations, and
- basic support for interoperation with libraries written in
Scala.
The JavaScript compiler now supports type functions,
allowing the use of higher-order and higher-rank polymorphism
in Ceylon. These experimental features are not yet supported
by the Java compiler.
There are several new features and improvements to the
command line toolset:
- the
ceylon war command repackages a module as a Java EE
WAR archive,
- the
ceylon browse command opens module documentation in
the browser,
- multiple commands can be given simultaneously, for example
ceylon compile,doc,run com.redhat.hello,
-
ceylon help command and ceylon --help now page output
by default, and
- the
ceylon command architecture now supports writing
plugins in Ceylon.
IDE
Ceylon IDE now features the following improvements, along
with many bugfixes and a number of performance enhancements:
- a brand new debugger for Ceylon,
- extensive support for new language features including
constructors and
native,
- improvements to the powerful Change Parameter List
refactoring,
- the Inline refactoring can now inline a type alias,
-
filtering of packages from searches and completions,
- many new quick fixes and assists,
-
Paste Java as Ceylon,
- the popup Outline can now show inherited members,
- the redesigned Open Declaration dialog now shows
documentation,
-
keyboard shortcuts were added for certain quick assists,
- support for Eclipse's new dark theme,
- refactored preferences pages, with much greater
customizability, including
- two new alternative syntax highlighting themes, along
with an alternative icon set.
A number of important subsystems have been abstracted and
rewritten in Ceylon, to support the ongoing development of
the new IntelliJ-based IDE for Ceylon.
SDK
The platform modules, recompiled for 1.2.0, are
available in the shared community repository, Ceylon Herd.
This release introduces two new platform modules:
-
ceylon.transaction provides support for distributed
transaction processing, and
-
ceylon.regex provides regular expressions.
Along with several API enhancements and bugfixes, including:
-
ceylon.time now has functions for parsing ISO 8601
formatted dates, times, and datetimes,
-
ceylon.locale now supports formatting zoned times, and
parsing dates and times,
-
ceylon.interop.java now has javaClassFromDeclaration(),
-
ceylon.net now has redirect(), and its Uri is now
immutable, and
- the collection types in
ceylon.collection now offer
additional named constructors.
OpenShift cartridge
The Ceylon cartridge for OpenShift has been improved
and updated to support Ceylon 1.2.
Web IDE
You can try Ceylon using the redesigned Web IDE, now
rewritten in Ceylon, and featuring syntax highlighting,
interactive error reporting, autocompletion, online
documentation, and persistence and code sharing via Gist.
The Web IDE serves a dual purpose as a standard example
demonstrating the use of Ceylon for web application
development and deployment to the OpenShift cloud
platform.
Source code
The source code for Ceylon, its specification, and its website,
is freely available from GitHub.
Information about Ceylon's open source licenses is available
here.
Issues
Bugs and suggestions may be reported in GitHub's
issue tracker.
Migrating from Ceylon 1.1
Migration from Ceylon 1.1 is easy. To recompile a module for
1.2:
- First ensure that its dependencies have also been
recompiled.
- If it imports a Ceylon SDK platform module, upgrade the
version number specified by the module
import statement
from "1.1.0" to "1.2.0" .
- If it imports any platform-native module, annotate its
module declaration native("jvm") or native("js"),
depending upon the target platform. This step does not
apply to cross-platform modules.
- If, when recompiling, you encounter errors on
assert
statements, try removing the assertion (the improvements
to flow typing now make some type assertions redundant).
Acknowledgement
As always, we're deeply grateful to the community volunteers
who contributed a substantial part of the current Ceylon
codebase, working in their own spare time. The following
people have contributed to Ceylon:
Gavin King, Stéphane Épardaud, Tako Schotanus, Tom Bentley,
David Festal, Enrique Zamudio, Bastien Jansen,
Emmanuel Bernard, Aleš Justin, Tomáš Hradec, James Cobb,
Ross Tate, Max Rydahl Andersen, Mladen Turk,
Lucas Werkmeister, Roland Tepp, Diego Coronel, Matej Lazar,
John Vasileff, Toby Crawley, Julien Viet, Loic Rouchon,
Stephane Gallès, Ivo Kasiuk, Corbin Uselton, Paco Soberón,
Michael Musgrove, Daniel Rochetti, Henning Burdack,
Luke deGruchy, Rohit Mohan, Griffin DeJohn, Casey Dahlin,
Alexander Altman, Alexander Zolotko, Alex Szczuczko,
Andrés G. Aragoneses, Anh Nhan Nguyen, Brice Dutheil,
Carlos Augusto Mar, Charles Gould, Chris Gregory, klinger,
Martin Voelkle, Mr. Arkansas, Paŭlo Ebermann, Vorlent,
Akber Choudhry, Renato Athaydes, Flavio Oliveri,
Michael Brackx, Brent Douglas, Lukas Eder, Markus Rydh,
Julien Ponge, Pete Muir, Nicolas Leroux, Brett Cannon,
Geoffrey De Smet, Guillaume Lours, Gunnar Morling,
Jeff Parsons, Jesse Sightler, Oleg Kulikov, Raimund Klein,
Sergej Koščejev, Chris Marshall, Simon Thum, Maia Kozheva,
Shelby, Aslak Knutsen, Fabien Meurisse, Sjur Bakka,
Xavier Coulon, Ari Kast, Dan Allen, Deniz Türkoglu,
F. Meurisse, Jean-Charles Roger, Johannes Lehmann, allentc,
Nikolay Tsankov, Chris Horne, Gabriel Mirea, Georg Ragaller,
Harald Wellmann, klinger, Oliver Gondža, Stephen Crawley.
