Set Contexts can only contain rules that have an associated 'Tag', a string associated with the head to identify the rule's applicability more quickly. A package context is related to its parent context in that any patterns within the package also become patterns within the parent context, with an appropriate prefix (a definition foo=3*x becomes InnerPackageNameoo=3*x`). The other instances of Set Contexts arise from packages.

Its dictionary is modified whenever a Set is run on a variable that is not otherwise scopes. The main example is the primary execution environment. We group five kinds of contexts with distinct behavior and restrictions:Ī Set Context is that defined by some set of Set operations (the function more commonly written =). A context consists of a set of replacement rules (its dictionary), and a priority in which they should be evaluated. Evaluation ContextsĪt any point, code is executing within a context.

It builds on Mathematica's tutorial/Evaluation page by explaining the order in which different rules are applied and explaining which functions are treated specially by the evaluation engine. It is probably less ideally suited as an introduction to Mathematica execution. This is supposed to explain the evaluation order as unambiguously as possible.

Wolfram mathematica tutorial