Action Notation 1


  Description
   The systematic informal description of action notation summarizes Action Notation, and gives further details. It is intended for reference.
  To make it self-contained, it starts by repeating most of the introduction to the concepts of actions, data, and yielders given in Semantic Entities.

  Actions
   Actions are essentially dynamic, computational entities. The performance of an action directly represents information processing behaviour and reflects the gradual, step-wise nature of computation. Items of data are, in contrast, essentially static, mathematical entities, representing pieces of information, e.g., particular numbers. Of course actions are `mathematical' too, in the sense that they are abstract, formally-defined entities, analogous to abstract machines defined in automata theory. A yielder represents an unevaluated item of data, whose value depends on the current information, i.e., the previously-computed and input values that are available to the performance of the enclosing action. For example, a yielder might always evaluate to the datum currently stored in a particular cell, which could change during the performance of an action.

  Action Notation