Alef (programming language)

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Alef
Paradigm(s) compiled, concurrent, structured
Designed by Phil Winterbottom
Appeared in 1992
Typing discipline Static, strong
Influenced by C, Newsqueak
Influenced Limbo, Rust, Go
OS Plan 9 from Bell Labs

Alef was a 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.

History[edit]

Alef appeared in the first and second editions of Plan 9, but was abandoned during development of the third edition.[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Alef was superseded by two programming environments.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. The Alef concurrency model was replicated in the third edition of Plan 9 in the form of the libthread library, which makes some of Alef's functionality available to C programs and allowed existing Alef programs (such as Acme) to be translated.[5]

Example[edit]

This example was taken from the Alef reference manual.[1] The piece illustrates the use of tuple data type.

 (int, byte*, byte) 
 func() 
 { 
  return (10, "hello", ’c’); 
 }
 void 
 main() 
 {
   int a; 
   byte* str; 
   byte c; 
   (a, str, c) = func(); 
 }

See also[edit]

References[edit]

  1. ^ a b Winterbottom, Phil (1995). "Alef Language Reference Manual". Plan 9 Programmer's Manual: Volume Two. Murray Hill: AT&T. 
  2. ^ "Preface to the Third (2000) Edition". Plan 9 Manual. Murray Hill: Bell Labs. June 2000. Retrieved 2012-10-29. 
  3. ^ Origins of Go concurrency style. Talk by Pike at OSCON's Emerging Languages Camp 2010.
  4. ^ Pike, Rob. "Rio: Design of a Concurrent Window System". Retrieved 8 March 2013. 
  5. ^ "thread(2)". Plan 9 Manual. Retrieved 2012-10-29.