Alef is a discontinued concurrent programming language, designed as part of the Plan 9 operating system by Phil Winterbottom of Bell Labs.
It implemented the channel-based concurrency model of Newsqueak in a compiled, C-like language.
[1][2] Rob Pike later explained Alef's demise by pointing to its lack of automatic memory management, despite Pike's and other people's urging Winterbottom to add garbage collection to the language;[3] also, in a February 2000 slideshow, Pike noted: "…although Alef was a fruitful language, it proved too difficult to maintain a variant language across multiple architectures, so we took what we learned from it and built the thread library for C."[4] Alef was superseded by two programming environments.
The Limbo programming language can be considered a direct successor of Alef and is the most commonly used language in the Inferno operating system.
[1] The piece illustrates the use of the tuple data type.