Decision Table Hit Policies

The hit policy controls how many rules may match a given input and, if more than one matches, which output wins. Every decision table must declare a hit policy.

For background on how decision tables are structured in RASON, see Business Rules & Decision Tables.

U — Unique (the policy used in the Decision Tables example)

"hitPolicy": "U" is the strictest single-hit policy. Rules must not overlap — for any possible input, at most one rule can match. If two rules match the same input, the table is in error. Use Unique when your rules form a true partition of the input space and you want overlaps caught as errors.

All Hit Policies

Code	Name	Family	Behavior
U	Unique	Single-hit	Rules must not overlap; at most one rule may match. Overlap is a table error.
F	First	Single-hit	Rules may overlap; the first matching rule wins.
A	Any	Single-hit	Rules may overlap, but all matches must produce the same output. Disagreement is a table error.
P	Priority	Single-hit	Rules may overlap; the match with the highest-priority output wins.
C	Collect	Multiple-hit	All matching rules contribute their outputs, returned as a list.
C+	Collect / sum	Multiple-hit	Sums the outputs of all matching rules.
C<	Collect / min	Multiple-hit	Returns the smallest output among all matching rules.
C>	Collect / max	Multiple-hit	Returns the largest output among all matching rules.
C#	Collect / count	Multiple-hit	Returns the number of rules that matched.
R	Rule order	Multiple-hit	Returns outputs of all matching rules, in the order listed.
O	Output order	Multiple-hit	Returns outputs of all matching rules, ordered by decreasing output priority.