FUNCTION (Member)
Declares or defines a member procedure returning a value
Syntax:
{ Type | Class | Union } typename
Function typename.fieldname ( [ parameters ] ) [ byref ] as datatype [ Export ]
declare [ static | const ] Function fieldname [calling convention specifier] [ alias external_name ] ( [ parameters ] ) [ byref ] as datatype [ Static ]
End { Type | Class | Union }Function typename.fieldname ( [ parameters ] ) [ byref ] as datatype [ Export ]
statements
End FunctionParameters:
typename
fieldname
fieldname
name of the procedure
external_name
name of field as seen when externally linked
parameters
the parameters to be passed to the procedure
calling convention specifier Description:
Function members are accessed with Operator . (Member access) or Operator -> (Pointer to member access) to call a member procedure that returns a value (a reference can also be returned by specifying byref as return_type). The procedure may optionally accept parameters either byval or byref. typename be overloaded without explicit use of the Overload keyword.
typename is the name of the type for which the Function method is declared and defined. Name resolution for typename follows the same rules as procedures when used in a Namespace.
A hidden this parameter having the same type as typename is passed to non-static member procedures. this is used to access the fields of the Type, Class, or Union.
To access duplicated symbols defined as global outside the Type, add one or preferably two dot(s) as prefix: .SomeSymbol or preferably ..SomeSymbol (or only ..SomeSymbol if inside a With..End With block).
A Static (Member) may be declared using the Static specifier. A Const (Member) may be declared using the Const specifier.
As for a normal Function, the return value of a Function member can be ignored in the calling code.
typename is the name of the type for which the Function method is declared and defined. Name resolution for typename follows the same rules as procedures when used in a Namespace.
A hidden this parameter having the same type as typename is passed to non-static member procedures. this is used to access the fields of the Type, Class, or Union.
To access duplicated symbols defined as global outside the Type, add one or preferably two dot(s) as prefix: .SomeSymbol or preferably ..SomeSymbol (or only ..SomeSymbol if inside a With..End With block).
A Static (Member) may be declared using the Static specifier. A Const (Member) may be declared using the Const specifier.
As for a normal Function, the return value of a Function member can be ignored in the calling code.
Examples:
#include "vbcompat.bi"
Type Date
value As Double
Declare Static Function Today() As Date
Declare Function Year() As Integer
Declare Function Month() As Integer
Declare Function Day() As Integer
End Type
Function Date.Today() As Date
Return Type(Now())
End Function
Function Date.Year() As Integer
Return ..Year(value)
End Function
Function Date.Month() As Integer
Return ..Month(value)
End Function
Function Date.Day() As Integer
Return ..Day(value)
End Function
Dim d As Date = Date.Today
Print "Year = "; d.Year
Print "Month = "; d.Month
Print "Day = "; d.Day
Type Date
value As Double
Declare Static Function Today() As Date
Declare Function Year() As Integer
Declare Function Month() As Integer
Declare Function Day() As Integer
End Type
Function Date.Today() As Date
Return Type(Now())
End Function
Function Date.Year() As Integer
Return ..Year(value)
End Function
Function Date.Month() As Integer
Return ..Month(value)
End Function
Function Date.Day() As Integer
Return ..Day(value)
End Function
Dim d As Date = Date.Today
Print "Year = "; d.Year
Print "Month = "; d.Month
Print "Day = "; d.Day
Dialect Differences:
- Only available in the -lang fb dialect.
See also:
Back to User Defined Types