Depth of Inheritance Tree (DIT)

Title short form	DIT
Categories	Maintainability
Definition	Number of inheritances until a function block is reached that does not extend any other function block
Further information	DIT = Depth of Inheritance Tree

Sample:

FUNCTION_BLOCK FB_Base

FUNCTION_BLOCK FB_Sub EXTENDS FB_Base

FUNCTION_BLOCK FB_SubSub EXTENDS FB_Sub

The metric Depth of Inheritance Tree is:

For FB_Base: 0, as it is itself a function block that does not extend any other function block.
For FB_Sub: 1, as one step is required to get to FB_Base.
For FB_SubSub: 2, as one step to FB_Sub and another to FB_Base is required.