DMNFTF — "Evaluation of the expressions in a decision table does not produce side-effects."

"Evaluation of the expressions in a decision table does not produce side-effects." Since those expressions can include calls to external Java code, this Ain't Necessarily So. Better to put this outside the scope of conforming implementations by saying something like: "Where expressions in a decision table are are expressed solely in FEEL, with no externally-defined functions, their evaluation does not produce side-effects. The behaviour of decision tables that call externally-defined functions with side-effects is undefined."

Expand on the definition and rationale for no side-effects. We say elsewhere that externally defined functions should not have side-effects - this is true in general and is not specific to decision tables.