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08-Jan-2016 08:44
Version 2.1.1 Released#

We have released version 2.1.1 of Orc, a minor update. This release makes no language changes. The release does improve the Orc Eclipse plug-in and extends the standard library slightly. In addition, significant work has gone into improving the underlying implementation.

There are multiple ways to run Orc:

1. Use our Try Orc ( ) feature to experiment with Orc in your Web browser.

2. Use the Orc plug-in for Eclipse, available as "Orc" on the Eclipse Marketplace. (In Eclipse, use the menu item Help > Eclipse Marketplace) If you already have the Orc plug-in for Eclipse installed, use the Check for Updates menu item to get the update.

3. Orc is also available as a standalone JAR which you can use to run programs on the command line. You can download the release archive from GitHub at .

Happy Orcing,

--The Orc Language Research Team

05-Jun-2015 23:52
Orc on GitHub#

With the shutdown of Google Code Project Hosting, we have migrated to GitHub. This, of course, means that we have changed our version control system to git.

All of the Orc source repository, release files, and issues (including history of each) is now available at

Be sure to "star" the orc-lang/orc repo on GitHub.

21-Sep-2013 23:56
Version 2.1.0 Released#

Orc 2.1 is a new revision of the Orc implementation. This release is backward compatible with all Orc 2.0 programs, however it does have a few language improvements and extensions. In addition, significant work has gone into improving the underlying implementation.

See our Downloads page for detailed instructions on how to download and use Orc within Eclipse, locally within your Web browser, or from the command line.


  • Support for virtual clocks.
  • Optional declaration-expression separator "#" added that disambiguates the end of a declaration.
  • InvokeExecutable class in the standard library allows Orc to spawn OS processes.
  • Sites added to the standard library: zipWith, listToJavaList, listToArray.
  • Support for Unicode escapes in Orc strings.


  • Updated Scala dependency to 2.10.
  • Fix blocking on strict site call arguments; if any argument halts the entire call will halt regardless of the state of other arguments.
  • Improved runtime error messages.
  • Documentation of the Orc standard library has been expanded and improved.
10-Sep-2012 09:41
Orc on Android#

An experimental port of Orc to the Android platform has been performed by by Ricardo Bernardino and João Barbosa of the University of Coimbra as part of a UT Austin|Portugal CoLab project. See the OrcAndroid page.

05-Mar-2010 17:12
Version 1.1.0 Released#

See our Downloads page for detailed instructions on how to download and use Orc within Eclipse, locally within your web browser, or from the command line.

This release is backwards compatible with Orc 1.0. Any Orc program that runs under Orc 1.0 with no command line switches will also run under Orc 1.1, with the same behavior.

Major updates:

  • The Orc implementation has been updated to Java 6, since Java 5 is now deprecated.
  • The execution model for Orc programs has changed substantially. The compiler no longer generates a directed acyclic graph from the OIL abstract syntax tree; instead it executes directly on that syntax tree.
  • A new definition, capsule, is now available. Orc capsules provides this facility for programmer to define active objects in Orc. The creation and execution of capsule is protected from the execution and termination of the rest of the program. capsule is documented in the user guide.
  • A new site, Site, is now available. It takes a single argument, which must be a closure, and returns a site which, when called, executes that closure as if it were a site.

Minor updates:

  • URLs may be used in include declarations. This is especially helpful when using a web-based interface, as it allows access to include files hosted on another server.
  • Unused function definitions are now trimmed from the program AST during compilation; this substantially decreases compile time and sometimes improves performance as well.
  • There is a new -noexecute switch which suppresses execution of a program, performing only compilation. Typically this is used in concert with -typecheck or -oilOut.
  • The Top type is now interchangeable with java.lang.Object; this is a minor weakening of the type theory, but in practice it is useful and causes no problems.
  • The signal value now has a unique type, Signal. This is analogous to the unit type in typed functional languages such as ML.
  • Calls to the Record site which use string literals for field names are now statically typable.
  • Type parameters may now be written inline in defs and lambdas.
  • The experimental isolated keyword has been removed entirely. Its functionality is mostly subsumed by the Site site.
  • The stub code for the atomic combinator has been removed entirely. A full implementation of atomic will be added to a future release of Orc.
  • The OAuth protocol used in OrcSites and Orchard has been updated to protocol version 1.0a.
  • In the Orc Eclipse plug-in:
    • The outline view distinguishes between function definition clauses and function signatures.
    • The New Orc file wizard is improved.
    • Orc program run configurations now have an Alternative Orc Runtime Engine tab, to allow programs to run with an Orc Runtime Engine other than the built-in one. This permits experimenting with, and debugging of, the Orc language runtime.
    • If not specified, the working directory of a program is now the directory containing the program.
    • JavaSE 6 (or newer) is now required.
  • The Orchard WAR/JAR bundling has been completely re-worked: now orchard.war bundles only Orc-specific JARS in its lib; "common" JARs, such as JAX-WS are external.
  • The Orchard "try Orc" demo has much friendlier error handling.
12-Apr-2009 19:46
Google Code, Subversion, and v0.9.8#

This weekend the project made some major administrative changes.

  • Most importantly, we changed project hosting from SourceForge to Google Code. All SourceForge services are now deactivated, including CVS and hosting of old releases. Old releases are available in source code form via version control; if there is demand for pre-packaged binaries of old releases, I can put them on Google Code.
  • We changed version control systems from CVS to Subversion. Google Code has the SVN repository information. For more details on the switch, see MigratingToSvn.
  • We changed our source code license to the "New" BSD license. The new license has more liberal terms than our previous license (which forbade commercial use) so this should not affect anybody already using our code.
  • We cleaned up our library dependencies to ensure we are complying with licensing terms for all bundled third-party libraries.
  • We released version 0.9.8, primarily to make the binaries available under the new license.
13-Mar-2009 01:04
CVS Outage#

Our project's SourceForge CVS repository has been inaccessible since sometime yesterday evening. According to service will not be restored until sometime Friday. Apologies for any inconvenience.

UPDATE Fri Mar 13 1am: CVS service appears to be restored now.

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« This page (revision-4) was last changed on 09-Jun-2016 15:41 by John Thywissen