Racket 6.8 发布，Lisp 语言分支

Racket 6.8 发布了，该版本包含如下改进内容：

• Racket sports a new logo, courtesy of Matthew Butterick.

• MacBook Pro laptops with touch bars are supported.

• Support for FreeBSD on PowerPC.

• Initial support for GTK3 on Wayland is available. GL contexts, GC blits, and dialog placement currently do not work.

• The macro stepper provides a command-line interface via the raco macro-stepper command.

• Typed Racket more efficiently represents and computes types and propositions, resulting in faster type checking for many programs. For more details, see this blog post by Andrew Kent .

• The bytecode optimizer can reduce more expressions of the form (equal? x y) to (eqv? x y) or (eq? x y) when the type of x or y is known.

• The bytecode optimizer avoids dropping stack frames in some reductions. This provides better stack traces for errors when errotrace is enabled.

• The bytecode compiler detects more optimization opportunities, including when variables always hold a boolean value. In particular in expressions like (or (symbol? x) (something)), the optimizations avoid the creation of an intermediate variable to store the result of (symbol? x).

• The syntax form preserves syntax properties on all template pieces.

• The scribble/html/extra module provides renderers for HTML elements that are part of the WHATWG HTML standard but not part of the scribble/html language by default (e.g., map, time, video).

• The DeinProgramm teaching languages support pattern matching using the match form.

• In the DeinProgramm languages, define-record-procedures supports specifying signatures as part of the form, instantly enabling properties quantifying over such records.

下载地址： https://download.racket-lang.org/

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。