dot-propagate_domains: Propagate domains between steps

In cohortBuilder: Data Source Agnostic Filtering Tools

Propagate domains between steps

Description

Source-layer generic that recomputes the domains of a **target step** from that step's parent (the previous step). Override to implement dynamic domain narrowing.

Usage

.propagate_domains(source, data_object, step_id, cohort, ...)

## Default S3 method:
.propagate_domains(source, data_object, step_id, cohort, ...)

## S3 method for class 'tblist'
.propagate_domains(source, data_object, step_id, cohort, mode, ...)

Arguments

source	Source object.
data_object	Filtered data of the **parent** step (the input to the target step), used by 'mode = "data"'.
step_id	Target step id whose domains should be recomputed.
cohort	Cohort object (for accessing the parent step's filters and stored statistics).
...	Additional arguments.
mode	Propagation mode: '"filter"' (from upstream filter values, no data access), ‘"stats"' (from the parent’s post-step stored stats), or '"data"' (scan the parent's filtered data directly).

Details

The default is a no-op. Only called when 'propagate_domains != "none"' in the Cohort.

Contract: ‘step_id = N' recomputes the domains of step 'N'’s filters using step 'N - 1' as the source of truth. It is a no-op when 'N' has no parent (i.e. 'N == "1"') or when the target step is absent.

cohortBuilder documentation built on July 3, 2026, 9:07 a.m.