Temporary Types
Creates a temporary copy of a user defined type
result = Type( initializers, ... )
A temporary copy of the type.
Used to create a temporary type. If typename is not explicitly given, it will be inferred from its usage if possible. Usage of the temporary copy may include assigning it to a variable, passing it as a parameter to a procedure, or returning it as a value from a procedure.
For a type without constructor, the temporary type syntax is allowed if all type data-fields are numeric primitives only and without any default initializers, but the compiler does a direct assignment instead of using a temporary copy if at same time the type is without destructor.
The Constructor for the type, if there is one, will be called when the temporary copy is created, and the Destructor for the type, if there is one, will be called immediately after its use. But when there is a constructor, the temporary type expression may be simply replaced by typename( initializers, ... ).
It can create not only a temporary copy of an user defined type, but also a temporary copy of predefined data-type as a variable-length string or any numeric data-type (all standard data-types excluding fixed-length strings).
It can also be used as an even shorter shortcut than With (see below) if you are changing all the records.
Syntax
result = Type( initializers, ... )
or
result = Type<typename>( initializers, ... )Parameters
Return Value
A temporary copy of the type.
Description
Used to create a temporary type. If typename is not explicitly given, it will be inferred from its usage if possible. Usage of the temporary copy may include assigning it to a variable, passing it as a parameter to a procedure, or returning it as a value from a procedure.
For a type without constructor, the temporary type syntax is allowed if all type data-fields are numeric primitives only and without any default initializers, but the compiler does a direct assignment instead of using a temporary copy if at same time the type is without destructor.
The Constructor for the type, if there is one, will be called when the temporary copy is created, and the Destructor for the type, if there is one, will be called immediately after its use. But when there is a constructor, the temporary type expression may be simply replaced by typename( initializers, ... ).
It can create not only a temporary copy of an user defined type, but also a temporary copy of predefined data-type as a variable-length string or any numeric data-type (all standard data-types excluding fixed-length strings).
It can also be used as an even shorter shortcut than With (see below) if you are changing all the records.
Example
Type Example
As Integer field1
As Integer field2
End Type
Dim ex As Example
'' Filling the type by setting each field
ex.field1 = 1
ex.field2 = 2
'' Filling the type by setting each field using WITH
With ex
.field1 = 1
.field2 = 2
End With
'' Fill the variable's fields with a temporary type
ex = Type( 1, 2 )
As Integer field1
As Integer field2
End Type
Dim ex As Example
'' Filling the type by setting each field
ex.field1 = 1
ex.field2 = 2
'' Filling the type by setting each field using WITH
With ex
.field1 = 1
.field2 = 2
End With
'' Fill the variable's fields with a temporary type
ex = Type( 1, 2 )
'' Passing a user-defined types to a procedure using a temporary type
'' where the type can be inferred.
Type S
As Single x, y
End Type
Sub test ( v As S )
Print "S", v.x, v.y
End Sub
test( Type( 1, 2 ) )
'' where the type can be inferred.
Type S
As Single x, y
End Type
Sub test ( v As S )
Print "S", v.x, v.y
End Sub
test( Type( 1, 2 ) )
'' Passing a user-defined type to a procedure using temporary types
'' where the type is ambiguous and the name of the type must be specified.
Type S
As Single x, y
End Type
Type T
As Integer x, y
End Type
Union U
As Integer x, y
End Union
'' Overloaded procedure test()
Sub test Overload ( v As S )
Print "S", v.x, v.y
End Sub
Sub test ( v As T )
Print "T", v.x, v.y
End Sub
Sub test ( v As U )
Print "U", v.x, v.y
End Sub
'' Won't work: ambiguous
'' test( type( 1, 2 ) )
'' Specify name of type instead
test( Type<S>( 1, 2 ) )
test( Type<T>( 1, 2 ) )
test( Type<U>( 1 ) )
'' where the type is ambiguous and the name of the type must be specified.
Type S
As Single x, y
End Type
Type T
As Integer x, y
End Type
Union U
As Integer x, y
End Union
'' Overloaded procedure test()
Sub test Overload ( v As S )
Print "S", v.x, v.y
End Sub
Sub test ( v As T )
Print "T", v.x, v.y
End Sub
Sub test ( v As U )
Print "U", v.x, v.y
End Sub
'' Won't work: ambiguous
'' test( type( 1, 2 ) )
'' Specify name of type instead
test( Type<S>( 1, 2 ) )
test( Type<T>( 1, 2 ) )
test( Type<U>( 1 ) )
Differences from QB
- New to FreeBASIC
See also