Smalltalk

1 definition found

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  Smalltalk
       
           The pioneering {object-oriented programming} system
          developed in 1972 by the Software Concepts Group, led by {Alan
          Kay}, at {Xerox PARC} between 1971 and 1983.  It includes a
          language, a programming environment, and an extensive object


          library.
       
          Smalltalk took the concepts of {class} and {message} from
          {Simula-67} and made them all-pervasive.  Innovations included
          the {bitmap display}, windowing system, and use of a {mouse}.
       
          The {syntax} is very simple.  The fundamental construction is
          to send a message to an {object}:
       
          	object message
       
          or with extra parameters
       
          	object message: param1 secondArg: param2 .. nthArg: paramN
       
          where "secondArg:" etc. are considered to be part of the
          message name.
       
          Five pseudo-variables are defined: "self", "super", "nil",
          "true", "false".  "self" is the receiver of the current
          message.  "super" is used to delegate processing of a message
          to the {superclass} of the receiver.  "nil" is a reference to
          "nothing" (an instance of UndefinedObject).  All variables
          initially contain a reference to nil.  "true" and "false" are
          {Booleans}.
       
          In Smalltalk, any message can be sent to any object.  The
          recipient object itself decides (based on the message name,
          also called the "message selector") how to respond to the
          message.  Because of that, the {multiple inheritance} system
          included in the early versions of Smalltalk-80 appeared to be
          unused in practice.  All modern implementations have single
          inheritance, so each class can have at most one superclass.
       
          Early implementations were {interpreted} but all modern ones
          use {dynamic translation} (JIT).
       
          Early versions were Smalltalk-72, Smalltalk-74, Smalltalk-76
          (inheritance taken from Simula, and concurrency), and
          Smalltalk-78, {Smalltalk-80}.  Other versions include {Little
          Smalltalk}, {Smalltalk/V}, {Kamin's interpreters}.  Current
          versions are {VisualWorks}, {Squeak}, {VisualAge}, {Dolphin
          Smalltalk}, {Object Studio}, {GNU Smalltalk}.
       
          See also: {International Smalltalk Association}.
       
          {UIUC Smalltalk archive (http://st-www.cs.uiuc.edu/)}.
          {FAQ (http://XCF.Berkeley.EDU/pub/misc/smalltalk/FAQ/)}.
       
          {Usenet} newsgroup: {news:comp.lang.smalltalk}.
       
          ["The Smalltalk-76 Programming System Design and
          Implementation", D.H. Ingalls, 5th POPL, ACM 1978, pp. 9-16].
       
          (2001-09-11)