Intervals

Keep exact bounds

An interval keeps both endpoints in a single value, so uncertainty travels with the calculation. Interval arithmetic returns bounds rather than silently selecting one point.

Runnable RiXRun cell

a := 2:3; b := 4:5; a * b;

The product spans 8 through 15. These are exact endpoints; the value does not choose one number inside the range. Change an endpoint and predict how the bound changes.

Test betweenness

Three colon-separated values ask whether the middle one lies between the outer two. The first comparison is true and the second is false.

Runnable RiXRun cell

[2:7:10, 2:12:10];

See Number notation for more interval spellings and Recipe scaling for a calculation that carries a bound through a product.