Search results
Results from the WOW.Com Content Network
In C and C++, return exp; (where exp is an expression) is a statement that tells a function to return execution of the program to the calling function, and report the value of exp. If a function has the return type void, the return statement can be used without a value, in which case the program just breaks out of the current function and ...
This is conventional in languages (such as Python) that have a built-in tuple data type and special syntax for handling these: in Python, x, y = f() calls the function f returning a pair of values and assigns the elements of the pair to two variables. Secondary return values as in Common Lisp. All expressions have a primary value, but secondary ...
Since Python is a dynamically-typed language, Python values, not variables, carry type information. All variables in Python hold references to objects, and these references are passed to functions. Some people (including Guido van Rossum himself) have called this parameter-passing scheme "call by object reference".
The return statement, used to return a value from a function The import and from statements, used to import modules whose functions or variables can be used in the current program The match and case statements, an analog of the switch statement construct, that compares an expression against one or more cases as a control-of-flow measure.
For example, in the expression (f(x)-1)/(f(x)+1), the function f cannot be called only once with its value used two times since the two calls may return different results. Moreover, in the few languages which define the order of evaluation of the division operator's operands, the value of x must be fetched again before the second call, since ...
In a statement such as while ((ch = getchar ())!= EOF) {…}, the return value of a function is used to control a loop while assigning that same value to a variable. In other programming languages, Scheme for example, the return value of an assignment is undefined and such idioms are invalid.
Note that after calling (), we are left with a function that takes a single argument and returns another function, not a function that takes two arguments. In contrast, partial function application refers to the process of fixing a number of arguments to a function, producing another function of smaller arity.
In Common Lisp, the identifier of a function in the function namespace cannot be used as a reference to a first-class value. The special operator function must be used to retrieve the function as a value: (function foo) evaluates to a function object. #'foo exists as a shorthand notation.