Files
purchases-ios/Sources/RulesEngine/CustomOperators/LengthOperator.swift
T
Antonio PallaresandCursor cac918ca14 Add rc.indexOf custom operator (#7555)
* Add rc.indexOf custom operator

Arrays get a position, which nothing else expressed: in answers whether
a value is present, never where it sits.

Strings report the position through LengthOperator.stringLength, the
same function behind rc.length, so both operators always measure in one
unit and a later change to that unit moves them together.

Co-authored-by: Cursor <cursoragent@cursor.com>

* Frame stringLength as the engine's single string measurement

Co-authored-by: Cursor <cursoragent@cursor.com>

* Trim rc.indexOf doc comment

Co-authored-by: Cursor <cursoragent@cursor.com>

* Move stringLength out of the rc.length operator

It is the engine's measurement, not that operator's, and rc.indexOf had
to reach across to another operator to state a position in the same
unit. Mirrors the same move in purchases-android.

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>
2026-09-01 09:58:31 +00:00

50 lines
1.8 KiB
Swift

//
// LengthOperator.swift
//
// Created by Antonio Pallares.
//
import Foundation
extension RulesEngine {
/// `rc.length` — element count for arrays, UTF-16 code-unit count for
/// strings (JS `String.length` parity).
enum LengthOperator {
/// `{"rc.length": value}` — returns a numeric length suitable for
/// arithmetic and comparisons.
///
/// - **String**: length in **UTF-16 code units**, not Swift grapheme
/// clusters — matches JS `String.length` and the same choice in
/// `AccessorOperators.opMissingSome` (`string.utf16.count`).
/// - **Array**: element count (`.count`).
/// - **Anything else**: throws `EvaluationError.typeMismatch`.
///
/// Non-string/non-array inputs throw rather than defaulting to `0`.
/// A silent zero would make `{"==": [{"rc.length": {"var": "note"}},
/// 0]}` quietly true for a key that is present but holds `null`.
///
/// Uses `Operators.firstArgEvaluated` spread semantics; extra arguments
/// are silently ignored. Literal array operands must be wrapped
/// (e.g. `{"rc.length": [[1, 2, 3]]}`), not passed as a multi-element
/// arg list.
static func opLength(args: Value, vars: Scope) throws -> Value {
let input = try Operators.firstArgEvaluated(args, vars: vars)
switch input {
case .string(let string):
return .int(Int64(RulesEngineUtils.stringLength(string)))
case .array(let items):
return .int(Int64(items.count))
default:
throw EvaluationError.typeMismatch(
message: "operator 'rc.length' expected string or array, got \(input)"
)
}
}
}
}