Dynamic Environments

ToC

Allegro CL

ANSI Common Lisp

3 Evaluation and Compilation

3.1 Evaluation

3.1.1 Introduction to Environments

3.1.1.2 Dynamic Environments

A dynamic environment for evaluation is that part of an environment that contains bindings whose duration is bounded by points of establishment and disestablishment within the execution of the form that established the binding. A dynamic environment contains, among other things, the following:

bindings for dynamic variables.
information about active catch tags.
information about exit points established by unwind-protect.
information about active handlers and restarts.

The dynamic environment that is active at any given point in the execution of a program is referred to by definite reference as "the current dynamic environment," or sometimes as just "the dynamic environment."

Within a given namespace, a name is said to be bound in a dynamic environment if there is a binding associated with its name in the dynamic environment or, if not, there is a binding associated with its name in the global environment.