DescriptionStructure <name> [Extends <name>] ... EndStructure
Structure is useful to define user type, and access some OS memory areas. Structures can be used to enable faster and easier handling of data files. It is very useful as you can group into the same object the information which are common. Structures fields are accessed with the \ option. Structures can be nested. Statics arrays are supported inside structures.
Dynamic objects like arrays, lists and maps are supported inside structure and are automatically initialized when the object using the structure is created. To declare such field, use the following keywords: Array, List and Map.
The optional Extends parameter allows to extends another structure with new fields. All fields found in the extended structure will be available in the new structure and will be placed before the new fields. This is useful to do basic inheritance of structures.
SizeOf can be used with structures to get the size of the structure and OffsetOf can be used to retrieve the index of the specified field.
When using pointers in structures, the '*' has to be omitted when using the field, once more to ease API code porting. It can be seen as an oddity (and to be honest, it is) but it's like that since the very start of SpiderBasic and many, many sources rely on that so it won't be changed.
When using a lot of structure fields you can use the With : EndWith keywords to reduce the amount of code to type and ease its readability.
It's possible to perform a full structure copy by using the equal affectation between two structure element of the same type.
ClearStructure can be used to clear a structured memory area. It's for advanced use only, when pointers are involved.
Structure Person Name.s ForName.s Age.w EndStructure Dim MyFriends.Person(100) ; Here the position '0' of the array MyFriend() ; will contain one person and it's own information MyFriends(0)\Name = "Andersson" MyFriends(0)\Forname = "Richard" MyFriends(0)\Age = 32
Example: A more complex structure (Nested and static array)
Structure Window *NextWindow.Window ; Points to another window object x.w y.w Name.s ; 10 Names available (from 0 to 9) EndStructure
Example: Extended structure
Structure MyPoint x.l y.l EndStructure Structure MyColoredPoint Extends MyPoint color.l EndStructure ColoredPoint.MyColoredPoint\x = 10 ColoredPoint.MyColoredPoint\y = 20 ColoredPoint.MyColoredPoint\color = RGB(255, 0, 0)
Example: Structure copy
Structure MyPoint x.l y.l EndStructure LeftPoint.MyPoint\x = 10 LeftPoint\y = 20 RightPoint.MyPoint = LeftPoint Debug RightPoint\x Debug RightPoint\y
Example: Dynamic object
Structure Person Name$ Age.l List Friends$() EndStructure John.Person John\Name$ = "John" John\Age = 23 ; Now, add some friends to John ; AddElement(John\Friends$()) John\Friends$() = "Jim" AddElement(John\Friends$()) John\Friends$() = "Monica" ForEach John\Friends$() Debug John\Friends$() Next
Structure Person *Next.Person ; Here the '*' is mandatory to declare a pointer Name$ Age.b EndStructure Timo.Person\Name$ = "Timo" Timo\Age = 25 Fred.Person\Name$ = "Fred" Fred\Age = 25 Timo\Next = @Fred ; When using the pointer, the '*' is omitted Debug Timo\Next\Name$ ; Will print 'Fred'