A Wisdom Archive on Planner Programming Language - Control Structures Are Patterns Of Passing Messages

However, computer memories were very small by current standards because they were expensive, being made of iron ferrite cores at that time. So Planner adopted the then common expedient of using backtracking control structures to economize on the use of computer memory. In this way, the computer only had to store one possibility at a time in exploring alternatives. One implementation decision in Micro Planner had unfortunate consequences. Lisp had adopted the programming pun of identifying NIL, the empty list with logical ...

Read more here: » Planner programming language: Encyclopedia II - Planner programming language - Control Structure Controversy

In computer science, the Actor model, first published in 1973 (Hewitt et al. 1973), is a mathematical model of concurrent computation. The Actor model treats “Actors” as the universal primitives of concurrent digital computation: in response to a message that it receives, an Actor can make local decisions, create more Actors, send more messages, and determine how to respond to the next message received. The Actor model has been used both as a framework within which to develop a theor ... Including:

• Actor model - History
• Actor model - Fundamental concepts
• Actor model - Formal systems
• Actor model - Applications
• Actor model - Models prior to the Actor model
• Actor model - Lambda calculus
• Actor model - Simula
• Actor model - Smalltalk
• Actor model - Petri nets
• Actor model - Message Passing Semantics
• Actor model - The unbounded nondeterminism controversy
• Actor model - Direct communication and asynchrony
• Actor model - Actor creation plus addresses in messages means variable topology
• Actor model - Inherently concurrent
• Actor model - No requirement on order of message arrival
• Actor model - Not sequentiality not buffering not synchrony and not fixed topology
• Actor model - Locality
• Actor model - Compositionality
• Actor model - Behaviors
• Actor model - Relationship to mathematical logic
• Actor model - Migration
• Actor model - Security
• Actor model - Synthesizing addresses of Actors
• Actor model - Why is the Actor model important now?
• Actor model - Actor researchers

Read more here: » Actor model: Encyclopedia - Actor model

The Actor model built on previous models of computation. Actor model - Lambda calculus. The lambda calculus of Alonzo Church can be viewed as the earliest message passing programming language. For example the lambda expression below implements a tree data structure when supplied with parameters for a leftSubTree and rightSubTree. When such a tree is given a parameter message "getLeft", it returns leftSubTree and likewise when given th ...

Read more here: » Actor model: Encyclopedia II - Actor model - Models prior to the Actor model