Collection

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

Purpose and Interface

Adds notEmpty, empty, and countBetween checks for Array[V]. forEach builds a rule from a named array selector and an element predicate, reporting indexed paths. Filtering is expressed by a predicate passed to forEachWhere. forEachWhereIndexed accepts a custom indexer that names each included item in the failure path. ruleForEach starts a reusable ElementBuilder whose must, withMessage, withCode, whereItems, withIndex, and stopOnFirst operations compose multiple checks per element before buildEach freezes the rule.

Algorithm and edge cases

Element selection uses [[src/PuduLangValidator/Selection]] to match explicit and empty bracket indices at path boundaries.

Count bounds are rendered into failure messages when a check fails.

countBetween attaches From, To, and computed TotalCount arguments for caller messages.

Each element is visited in ascending index order. Filtering preserves original indices. A simple element predicate yields one failure; an element builder may yield several in check order, unless stopped after the first failure. Selected indexed paths skip other elements. The element message may use {CollectionIndex} and {PropertyPath}. A custom indexer supplies the bracket content, while {CollectionIndex} stays the numeric source position. An empty array produces no element failures.

Negative logic

No enumerable reflection or mutation during iteration.

Depth

MEDIUM — array checks and indexed failure construction.

Grill Log

• Q: Renumber filtered elements? A: Keep source indices. Rationale: paths should locate the actual item. Rejected: dense filtered numbering.
• Q: Implicit child validation? A: Require an explicit element predicate or child rule. Rationale: type and execution order stay visible. Rejected: reflection.

Referenced by

[[src/PuduLangValidator/Rules/_MOC]]