 
 
Unary Function
|  |  | 
| Category: functors | Component type: concept | 
Description
A Unary Function is a kind of function object: an object that is called
as if it were an ordinary C++ function.  A Unary Function is called with a
single argument.
Refinement of
Assignable
Associated types
| Argument type | The type of the Unary Function's argument. | 
| Result type | The type returned when the Unary Function is called | 
Notation
| F | A type that is a model of Unary Function | 
| X | The argument type of F | 
| Result | The result type of F | 
| f | Object of type F | 
| x | Object of type X | 
Definitions
The domain of a Unary Function is the set of all permissible
values for its argument.
The range of a Unary Function is the set of all possible values
that it may return.
Valid expressions
| Name | Expression | Type requirements | Return type | 
| Function call | f(x) |  | Result | 
Expression semantics
| Name | Expression | Precondition | Semantics | Postcondition | 
| Function call | f(x) | x is in f's domain | Calls f with x as an argument, and returns a value of type Result [1] | The return value is in f's range | 
Complexity guarantees
Invariants
Models
Notes
[1]
Two different invocations of f may return different results, even
if f is called with the same arguments both times.
A Unary Function may refer to local state, perform I/O,
and so on.  The expression f(x) is permitted to change f's state.
See also
Function Object overview, Generator, Binary Function
Adaptable Unary Function
 
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