- Submodules are nested module declarations that can be loaded and run independently from the enclosing module. See also the overview of submodules.
- The futures visualizer is a graphical profiling tool for parallel programs using futures. The tool shows a detailed execution timeline depicting the migration of futures between threads, and gives detailed information about each runtime synchronization that occurred during program execution. In addition, would-be-future is a special type of future that always executes sequentially and records all potential barricades a regular future would encounter.
- Optimization Coach (formerly Performance Report) reports information about Racket's inlining optimizations. Optimization Coach can be launched in any language through the View menu.
- The new images/flomap library defines floating-point bitmaps and fast image processing operations on them. It is written in Typed Racket, so Typed Racket code may use it without the cost of contract checks.
- The new json library supports parsing and generating JSON. (Originally based on Dave Herman's planet library.)
- racket/string is extended with a set of simplified string manipulation functions that are more convenient than using regexps. regexp-match* and friends can now be used with new keyword arguments to return specific matched regexp group/s and gaps between matches.
- The new racket/generic library allows generic function definitions, which dispatch to methods added to a structure type via the new #:methods keyword.
- The class form supports declaring a method abstract. An abstract method prevents a class from being instantiated unless it is overridden.
- The contract library comes with support for interfaces, generics, prompts, continuation-marks, and structs.
- Most error messages use a new multi-line format that is more consistent with contract errors and accommodates more information.
- Typed Racket supports function definitions with keyword arguments; the startup time of Typed Racket programs has been sharply reduced.
- The new ffi/com library replaces MysterX; a compatibility mysterx library remains, but without ActiveX support. The new ffi/unsafe/com library offers a more primitive and direct way to use COM classes and methods.
- There is now a very complete completion code for zsh. It is not included in the distribution though; get it at http://goo.gl/DU8JK (This script and the bash completions will be included in the standard installers in future versions.)
DeprecationEffective this release:
- The tex2page and combinator-parser libraries have been moved from the Racket distribution to PLaneT:
(require (planet plt/tex2page)) (require (planet plt/combinator-parser))
- The following has been deprecated and will be removed in the January 2013 release:
the planet command-line tool; use raco planet instead.
- The following has been deprecated and will be removed in the August 2013 release:
the mzlib/class100 library; use racket/class instead.