Child

type: module path: src/PuduLangValidator/Rules/Child.pudu

Purpose and Interface

setValidator applies a child validator to a nested value. setOptionalValidator skips None. forEachValidator applies a child validator to each array element.

Algorithm and edge cases

Child path translation uses [[src/PuduLangValidator/Selection]] to preserve wildcard indices across nested arrays.

Failures from children are copied in child order with a prefix: address.postcode or orders[2].total. Empty child property names resolve to the prefix itself. Collection indices are original indices. Child validators inherit selected rule sets, default-rule inclusion, and the property selection with their own prefix removed. Collection children at unselected indices are skipped.

Negative logic

No reflection, inheritance dispatch, or implicit child traversal.

Depth

MEDIUM — preserves nested failure locations across typed validator boundaries.

Grill Log

• Q: Validate absent optional child? A: Skip it. Rationale: absence is governed by an explicit presence rule. Rejected: fabricating child errors.
• Q: Should a child keep its original failure path? A: Prefix it. Rationale: callers need a location in the root model. Rejected: losing context.
• Q: How is the default set advertised for nested children? A: Collect named sets first, then append default once when any rule is unnamed. Rationale: the advertisement is order-free and each guard is observable. Rejected: a per-rule guard whose named-rule arm no nested run can observe.

Referenced by

[[src/PuduLangValidator/Rules/_MOC]]