In mathematical terms, an associative array is a function with finite domain Apply function apply is also the name of a special function in many languages, which takes a function and a list, and uses the list as the function's own argument list, as if the function were called with the elements of the list as the arguments. The former function is for expressions, while the latter is for statements a statement cannot be part of an expression
Because of this restriction, expressions such as list and dict comprehensions (and lambda expressions) cannot contain statements. Aside from specifying a function's binding, eval may also be used to evaluate an expression within a specific class definition binding or object instance binding, allowing classes to be extended with. Callable units provide a powerful programming tool
The ruby programming language interpreter offers an eval function similar to python or perl, and also allows a scope, or binding, to be specified
