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In lexical scope (or lexical scoping; also called static scope or static scoping), if a variable name's scope is a certain function, then its scope is the program text of the function definition: within that text, the variable name exists, and is bound to the variable's value, but outside that text, the variable name does not exist.
Local variables may have a lexical or dynamic scope, though lexical (static) scoping is far more common.In lexical scoping (or lexical scope; also called static scoping or static scope), if a variable name's scope is a certain block, then its scope is the program text of the block definition: within that block's text, the variable name exists, and is bound to the variable's value, but outside ...
Dynamic binding (or late binding or virtual binding) is name binding performed as the program is running. [2] An example of a static binding is a direct C function call: the function referenced by the identifier cannot change at runtime. An example of dynamic binding is dynamic dispatch, as in a C++ virtual method call.
A somewhat common misconception is that dynamic typing implies dynamic name resolution. For example, Erlang is dynamically typed but has static name resolution. However, static typing does imply static name resolution. Static name resolution catches, at compile time, use of variables that are not in scope; preventing programmer errors.
The term closure is often used as a synonym for anonymous function, though strictly, an anonymous function is a function literal without a name, while a closure is an instance of a function, a value, whose non-local variables have been bound either to values or to storage locations (depending on the language; see the lexical environment section below).
In computer programming, a static variable is a variable that has been allocated "statically", meaning that its lifetime (or "extent") is the entire run of the program. This is in contrast to shorter-lived automatic variables, whose storage is stack allocated and deallocated on the call stack; and in contrast to dynamically allocated objects, whose storage is allocated and deallocated in heap ...
The term local variable is usually synonymous with automatic variable, since these are the same thing in many programming languages, but local is more general – most local variables are automatic local variables, but static local variables also exist, notably in C. For a static local variable, the allocation is static (the lifetime is the ...
Function bindings cannot be dynamically scoped using flet (which only provides lexically scoped function bindings), but function objects (a first-level object in Common Lisp) can be assigned to dynamically scoped variables, bound using let in dynamic scope, then called using funcall or APPLY.