In one embodiment, one or more computing systems executes a computer program defining (1) a bound value that references a bound variable and (2) a terminating bound value that references computation instructions for deriving a runtime value from at least the bound value of the bound variable. A computation orchestration layer of a programming framework initializes, according to the computer program, a subscription tracker that tracks subscription relationships between the bound variable and the terminating bound value. The computation orchestration layer uses, in response to receiving an indication of an update to the bound value of the bound variable, the subscription tracker to determine that the terminating bound value subscribes to updates to the bound value of the bound variable. The computation orchestration layer sends an update stream associated with the update to a callback function associated with the terminating bound value.