dynamic scope

In computer programming, scope is an enclosing context where values and expressions are associated. Various programming languages have various types of scopes. The type of scope determines what kind of entities it can contain and how it affects them -- or semantics. Scopes can:contain declarations or definitions of identifiers;contain statements and/or expressions which define an executable algorithm or part thereof;nest or be nested.
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<language> In a dynamically scoped language, e.g. most versions of Lisp, an identifier can be referred to, not only in the block where it is declared, but also in any function or procedure called from within that block, even if the called procedure is declared outside the block.
This can be implemented as a simple stack of (identifier, value) pairs, accessed by searching down from the top of stack for the most recent instance of a given identifier.
The opposite is lexical scope. A common implementation of dynamic scope is shallow binding.
(1996-07-11)