Racket 6.2 发布了，在这个版本中我们对核心库进行了优化和减缩，并将代码迁移到 Github 上。 目前核心库的源码请看 https://github.com/plt/racket, 和扩展包的源码 https://github.com/racket/. Racket源自著名的专家型语言PLT Scheme，同时又是Lisp语言的一个分支。它适用于从脚本Script到应用程序开发的任务执行工具，包括图形用户界面，Web服务器等。支持编译器的虚拟机，创建独立的可执行程序的工具，Racket Web服务器，具有丰富而全面的功能库，适用于初学者和专家编程。 其他改进内容包括： core repo * The package manager supports a direct references to Git repositories via "git://[...]", "http://[...].git", and "https://[...].git" URLs. (Previously, only references to GitHub were supported.) * A `--clone` option for `raco pkg install` or `raco pkg update` facilitates Git-based package development. If a package X has a Git repository source, installing and updating the package pulls from the repository in a read-only mode. Using `raco pkg update --clone X` switches the local installation to a repository checkout that is suitable for modifying the package implementation, issuing pull requests, pushing changes, and so on. Using `raco pkg update --lookup X` switches the package back to the default installation mode. drracket * Its on-line check syntax works with graphical content. * Increased availability of DrRacket's blueboxes, including method and constructor information. * The "Open Require Path" menu item supports ".." in relative pathnames. data * Added data/enumerate, a library that supports efficient enumeration of data structures redex * Its redex-check facility uses data (in addition to random) enumeration to try to find counter-examples. * Its generate-term function accepts additional arguments to return the "i"-th member of a pattern using data/enumerate (meaning it efficiently supports very large values of "i"). * The examples collection includes Launchbury's 1993 big-step lazy semantics. htdp * 2htdp/image's polygon may be built out of bezier curves instead of just straight lines (see the docs for "pulled-point"). * 2htdp/abstraction is a teachpack for instructors and students who wish to use for/* loops, match, define-type and type-cases in ISL and ISL+. * 2htdp/universe programs can be exported using DrRacket's executable creation mechanism and they behave properly when run independently. typed-racket * Typed Racket in DrRacket displays tooltips that show the types of expressions. Tooltips are also displayed for type errors. * Typed Racket loads generated contracts only when needed. This reduces memory use and startup time for Typed Racket programs. * Typed Racket has improved support for prefab structures, future semaphores, and async channels. * Typed Racket understands when two different variables refer to the same thing, and updates types accordingly. This particularly improves the type checking of macros such as `match` Racket 6.2 发布，Lisp 语言分支下载地址
