Look Back Blocking (Ext. Attr.)

Description

Look Back Blocking eliminates decisions where the specified standard or extended 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.

Parameters

This function block has the following parameters:

Parameter	Description
Always Evaluate	Hard, Soft or Breakable. Controls what happens when the extension eliminates all items in the range source.
	Hard	All items will remain eliminated. Enter a wait state after the logic script has completed.
	Soft	Roll back any eliminations made by this extension.
	Breakable	Roll back any eliminations made by this extension that have a danger point value of TRUE (non zero). Routing modules will first use the danger defined for each individual decision. However, one of the following may occur instead.
		If:	Then:
		No danger point has been configured for the decision.	The site-wide danger point will be used.
		This function block is used in the decision output logic.	The site-wide danger point will be used.
		No danger point can be found for a decision.	The decision remains eliminated.
Region Id	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.
Item Class	Class of the item.
Attribute	Name of the standard or extended attribute to compare.
Attribute Start Byte	Starting character within the standard or extended attribute.
Attribute Length	Specifies the number of characters in the attribute to compare. Enter zero in both the Start Character and Attribute Length fields to use all characters.

Note: All the function blocks that deal with extended attributes can be provided INTERNALHOLD text to read the value of an internal hold.

Values are:

0	Internal Hold is not set.
1	Internal Hold is set.

However, you cannot use any of the extended attribute function blocks to modify system attributes.

More information

	Look Back Blocking example.
	Look Back Blocking pseudo code.
	Routing function blocks list.