!!Version 2.0.0 Released

Orc 2.0 is a new major revision of the Orc implementation. The core codebase has been rewritten in Scala, and the internal structure of the compiler and runtime have been altered and improved substantially.  

The user-level surface language has also changed. Orc 2.0 is not backwards-compatible with previous versions of Orc. Here are the detailed release notes on the user-visible changes to the language.  Guidance on how to modify programs written in the previous version of Orc to make them run under Orc 2.0 is on the [UpgradingYourProgramToOrc2.0] page.

See our [Downloads|https://orc.csres.utexas.edu/download.shtml] page for detailed instructions on how to download and use Orc within Eclipse, locally within your web browser, or from the command line.

!! Added
* Support for records: record expressions, record types, record patterns, and record extension using {{+}}
* Function clauses may have arbitrary guard conditions.
* New {{web}} library section, with sites {{Browse}}, {{HTTP}}, {{~ReadJSON}}, and {{~WriteJSON}}
* New {{xml}} library section, with XML manipulation sites.
* Enhanced parse error messages.
* Enhanced compiler and runtime error messages, with links into the Orc Wiki.
* The {{.oil}} compiled representation of Orc programs now has a standard public format, given by {{orc.csres.utexas.edu/oil.xsd}}.
* Orc compiler and runtime support JSR 223.
* Orc 2.0 has a full Reference Manual.
* Added site {{~IterableToStream}} to convert Java objects implementing {{Iterable}} to a more Orc-appropriate idiom.
* Any value with an {{apply}} member can be called; the call is forwarded to the {{apply}} member.
* Any value with an {{unapply}} member can be used in a call pattern; the match target is forwarded to the {{unapply}} member.

!! Modified
* {{def capsule}} is now {{def class}}.
* {{site}} is now {{import site}}.
* {{class}} is now {{import class}}.
* {{type}} is now {{import type}} for external types. Type aliases and datatypes remain unchanged.
* The three {{import}} declarations require the Java class name to be a quoted string.
* The comparison operators {{<}} and {{>}} are now {{<:}} and {{:>}}.
* {{if}} site is now {{Ift}}. {{Ift}} has a counterpart, {{Iff}}.
* {{IArray}} is now {{Table}}.
* {{Rtimer}} is now {{Rwait}}.
* {{Buffer}} is now {{Channel}}. {{~BoundedBuffer}} is now {{~BoundedChannel}}.
* "Nonblocking" sites, with the suffix '{{nb}}', are now "definite" sites, with the suffix '{{D}}'.
* Site names are now capitalized by convention. This has changed many sites in the standard library: {{Let}}, {{Print}}, {{Println}}, {{Error}}, {{Read}}, {{Write}}, {{Floor}}, {{Ceil}}, {{Random}}, {{URandom}}.
* Keywords are reserved.  (Previously one could, for example, define a function named "stop".)
* Orc identifiers may now use Unicode letters.
* Fixed bugs in {{Floor}} and {{Ceil}}. 
* Arrays no longer have any methods.  They have one field, {{length}}. For {{slice}}, use the new function {{sliceArray}}.
* Arrays no longer pattern match as lists. Use {{arrayToList}}.
* Descendants of {{Iterable}} no longer pattern match as lists. Use {{iterableToList}}.
* All Orc programs and includes are interpreted using the UTF-8 character encoding.

!! Removed
* Tracing facilities have been removed.
* Experimental support for Orc exception handling syntax has been removed.
* Special treatment of interaction between {{if then else}} and {{>>}} in parser has been removed.
* {{if then}} without {{else}} is no longer supported. Always use {{if then else}}.
* Equality ({{=x}}) pattern is gone. Use a guard on the clause instead.
* Special treatment of newlines has been removed.  Ambiguous syntax can be eliminated with the insertion of {{signal >>}}.
* Curried definition of functions, lambdas, and function types are no longer allowed. Expand these explicitly as chained lambdas instead.
* {{Record}} has been removed; use primitive records instead.
* {{Set}} and {{Map}} have been removed; use Scala or Java counterparts instead.
* {{cat}} has been removed, use {{+}} on strings instead.
* {{Clock}} has been removed, use {{Rclock}} instead.
* {{Ltimer}} and {{withLtimer}} have been removed.
* {{Apply}} has been removed.
* {{Thread}} has been removed.
* {{()}} as a synonym for {{signal}} has been removed.
* All uses of and dependencies on Kilim have been removed.