Literature/1975/Dijkstra

Semantics
At the moment G is encountered in a calculation, it is evaluated.
 * If G is true, execute S.
 * If G is false, look at the context to decide what to do (in any case, do not execute S).

Related works

 * (1976). A Discipline of Programming. Prentice-Hall Series in Automatic Computation. A systematic introduction to a version of the guarded command language with many worked examples.