I suggest to dynamically generate a default for the End-date field that adds 19 years to whatever the user has entered in the Start-date field (for dates at least prior to 9979-12-12.

Two potential ways to implement are:

(a) A default entry into the End-Date field, that lets the user change to some other date. This more work than it's worth. So maybe...
(b) A simple message-box could just appear beside the End-Date field that says: "When a rule specifies no End-Date, our conventional default is 'StartDate' + 19 years: 20XX-YY-ZZ. Rationale: https://founders.archives.gov/documents/Madison/01-12-02-0248

Background:

I find that when I am structuring sample rules with RuleMaker, almost always I have to arbitrarily guess at an end date, since most rule sources don't state any end dates. Often I write examples with a completely arbitrary date or I enter 9999-12-12 | 23:59:59 which are both shoddy work-arounds.

Finally though, we have a logical externally-sourced default end-date when the rule source does not specify one!

In this article the Craig recently pointed to https://www.networklawreview.org/computational-one/ ...I noticed the following:

"Every law ought to expire after nineteen years. Jefferson’s argument rested on the view that it is fundamentally unjust for people in the present to create laws for those in the future"

A quick search led me to this article https://chicagounbound.uchicago.edu/cgi/viewcontent.cgi?article=1064&context=public_law_and_legal_theory ...where I see the following elaboration:

Jefferson said, “[e]very constitution . . . and every law,” should “naturally expire[] at the end of 19 years.” (Jefferson elaborately calculated, on the basis of life expectancies at the time, that a majority of people 21 and older would die within 19 years, and concluded that that was the best measure of a generation’s life span. (Footnote: Letter of July 12, 1816, to Samuel Kercheval; see also Letter of Sept. 6, 1789.)

Then I found the full text of the original: https://founders.archives.gov/documents/Madison/01-12-02-0248

The length of that term may be estimated from the tables of mortality, corrected by the circumstances of climate, occupation &c. peculiar to the country of the contractors. Take, for instance, the table of M. de Buffon wherein he states 23,994 deaths, & the ages at which they happened.2 Suppose a society in which 23,994 persons are born every year, & live to the ages stated in this table. The conditions of that society will be as follows. 1st. It will consist constantly of 617,703. persons of all ages. Of those living at any one instant of time, one half will be dead in 24. years 8. months. 3dly. 10,675 will arrive every year at the age of 21. years complete. It will constantly have 348,417 persons of all ages above 21. years. 5ly. And the half of those of 21. years & upwards living at any one instant of time will be dead in 18. years 8. months, or say 19. years as the nearest integral number. Then 19. years is the term beyond which neither the representatives of a nation, nor even the whole nation itself assembled, can validly extend a debt.

I know that life expectancy in the 2020's is not the same as in the late 1700s (so the 19 should be extended), but also, I think the pace of change is faster in today's world (so the 19 seems to me useful to retain).

As an informal default, 19 seems about right to me.

It wont let me change the status but I would appreciate feedback!

Work like a charm. Thanks.