 

Category : functors   Component type: concept 
Description
A Unary Function is a kind of functors : 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
functors, Generator, BinaryFunction AdaptableUnaryFunction