title: Actor-Based Concurrent Language
text: # Actor-Based Concurrent Language
  
  Actor-Based Concurrent Language (ABCL) is a family of programming languages, developed in Japan in the 1980s and 1990s.
  
  ## ABCL/1
  
  ABCL/1 (Actor-Based Concurrent Language) is a prototype-based concurrent programming language for the ABCL MIMD system, created in 1986 by Akinori Yonezawa, of the Department of Information Science at the University of Tokyo.
  
  ABCL/1 uses asynchronous message passing among objects to achieve concurrency. It requires Common Lisp. Implementations in Kyoto Common Lisp (KCL) and Symbolics Lisp are available from the author.
  
  ### ABCL/c+
  
  An implementation of ABCL/c+ is available from the ACM.
  
  ### ABCL/R
  
  ABCL/R is an object-oriented reflective subset of ABCL/1, written by Professor Akinori Yonezawa of Tokyo Institute of Technology in 1988.
  
  **ABCL/R2**
  
  ABCL/R2 is a second generation version of ABCL/R, designed for the Hybrid Group Architecture. It was produced at the Tokyo Institute of Technology in 1992, and has almost all the functionality of ABCL/1. It is written in Common Lisp. As a reflective language, its programs can dynamically control their behavior, including scheduling policy, from within a user-process context.
  
  