BreakRule.Forced

Allowed carries an int preference for a selectable penalty. Negative values favor a break and positive values discourage it under the selected cost model. Zero is neutral. Every representable int remains an Allowed value rather than becoming a hard rule at a numeric threshold.

Forced requires every successful paragraph plan to end a line at that boundary. A plan cannot cross it or omit it to improve cost. If the required line cannot be admitted, planning returns the applicable TypesetError instead of ignoring the constraint.

Forbidden makes that penalty unselectable. It is not represented by a large Allowed preference. Penalty validation and duplicate-boundary rules determine the treatment of caller-supplied penalties at the same position.

BreakKind records a category and BreakRule records a planning constraint. Selecting a kind does not turn an Allowed penalty into Forced or Forbidden. The selected cost model interprets the Allowed preference and preserves both hard rules.

Constructing a rule creates an enum value and has no I/O or mutation. Allowed requires an int payload. An argument of another type is rejected with TPZ5001.