The this: scheme is used to access local state in the execution context of the current DPML program.

Scheme
this:[name]	A local reference to some execution state or context for the currently executing DPML program.
this:exception	If an exception occurs the exception resource is identified by this:exception .
this:param:[name]	The this:param: scheme allows a program to access named parameter arguments in a uniform manner regardless of whether they are pass-by-value or pass-by-reference. (The choice of method is made by the client code and does not impact how an accessor is coded when using this scheme.) Argument values are accessed by requesting a resource using this:param: followed by the name of the parameter.
this:response	When a DPML program ends it returns the resource saved to the identifier this:response. Instructions in a DPML program may write to (using the target child element) or read from this:response .