Jess,
An area of somewhat unclear documentation about how "Basic Patterns" are
interpreted, and I want to be sure before passing information on to our
customers. I have the following rule, pay attention to the TRANS_STATE
slot:
(defrule FC
?cast <-
(FC
(SQL_OPERATION "UPDATE" | "INSERT")
(TRANS_STATE ?trans_state & "SI" | "MI" | "EI")
(TRANS_STATE_last ~?trans_state)
(CTRLJOB_ID ?id)
)
=>
(printout t "FC: " ?id crlf)
)
My procedural view would be the pattern is evaluated as:
(TRANS_STATE (?trans_state & "SI") | "MI" | "EI")
And if the match for "SI" fails, not sure what ?trans_state would be.
However from testing, it looks like the binding is a byproduct of the
first test and the statement is really evaluated like:
(TRANS_STATE ?trans_state & ("SI" | "MI" | "EI"))
But to write this results in a compile time error.
BTW the original customer written rule has the TRANS_STATE slot twice in
the pattern match. This fails as it seems the binding to ?trans_state
isn't done, and thus the test for ~?trans_state always returns true.
(defrule Orig
?cast <-
(FC
(SQL_OPERATION "UPDATE" | "INSERT")
(TRANS_STATE "SI" | "MI" | "EI")
(TRANS_STATE ?trans_state)
(TRANS_STATE_last ~?trans_state)
(CTRLJOB_ID ?id)
)
=>
(printout t "Orig: " ?id crlf)
)
Jon
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