Look Back Blocking


Look Back Blocking eliminates decisions where the specified attribute in the tail item of the destination region match the corresponding attribute in one or more items following the head item of the source region.


This function block has the following parameters:



Always Evaluate

Hard, Soft or Breakable. This parameter controls what happens when the extension eliminates all available decisions.



All decisions will remain eliminated. Enter a wait state after the logic script has completed.



Roll back any decisions eliminated by this extension.



The routing modules will first use the danger defined for each individual decision.

If no danger point can be found for the decision the site-wide danger point is used.



TRUE (1)

Roll back any decisions eliminated by this extension.




The decision remains eliminated.


Region to search. If blank, each decision's source region will be searched.

Last Location

Number of locations to look back.

Item Class Class of item to compare.

Attribute ID

Attribute of first item to compare.

Start Character Starting character of the attribute to be used.

Attribute Length

Specifies the number of characters in attribute to compare.

Enter zero in both the Start Character and Attribute Length fields to use all characters.

More information

Look Back Blocking example.

Look Back Blocking pseudo code.

Routing function blocks list.