CSVCoder 1.0.0

[1.0.0] - 2026-05-15

First stable release.

Encoding

• CSVEncoder with configurable delimiter, quoting, header emission,
  nil handling, date strategy, number strategy, bool strategy, key
  encoding strategy, and nested-type encoding strategy.
• Sync entry points: encode(_:), encodeToString(_:), encode(_:to:URL).
• Streaming: encodeToStream(_:), encodeAsync(_:to:bufferSize:),
  encodeBatched(_:to:batchSize:bufferSize:).
• Parallel: encodeParallel(_:), encodeParallelBatched(_:to:batchSize:).
• Helpers: headers(for:sample:), encodeRow(_:), encodeToDictionary(_:).

Decoding

• CSVDecoder with configurable parsing mode (strict / lenient),
  trimming, expected field count, has-headers, key decoding strategy,
  column / index mapping, date strategy, number strategy, bool strategy,
  and nested-type decoding strategy.
• Sync entry points: decode([T].self, from: String / Data / URL).
• Streaming: decodeStream(_:from:), decodeBatched(_:from:batchSize:).
• Backpressure: decodeWithBackpressure(_:from:memoryConfig:),
  decodeBatchedWithBackpressure(_:from:memoryConfig:),
  decodeWithProgress(_:from:progressHandler:).
• Parallel: decodeParallel(_:from:parallelConfig:),
  decodeParallelBatched(_:from:parallelConfig:).

Macros

• @CSVRow generates CodingKeys (with CaseIterable),
  typealias CSVCodingKeys = CodingKeys, and conformances to
  CSVRowDecodable, CSVRowEncodable, and (when every stored property
  has a directly-supported type) CSVDirectDecodable.
• @CSVColumn("name") maps a property to a custom CSV header.
• Diagnostics for duplicate @CSVColumn names and orphan @CSVColumn
  on a struct without @CSVRow. Swift reserved-keyword property names
  are backtick-escaped automatically.

Direct-decode fast path

CSVDirectDecodable bypasses Codable's keyed-container indirection.
On Decode 1M rows (simple) (Apple M2 Pro, 5 iterations + 3 warmups)
the fast path measures 802 ms / ~1.25M rows/s versus 1638 ms /
~611K rows/s for the standard Codable path (≈2.04× speedup). Every
configuration option (trim, encoding, date/number strategies, nil
strategy, error locations) is honoured identically.

Strategies & locale support

• Key encoding / decoding strategies: snake_case, kebab-case,
  SCREAMING_SNAKE_CASE, PascalCase, and custom.
  convertToSnakeCase follows JSONEncoder._convertToSnakeCase —
  myURLProperty → my_url_property.
• Number decoding: standard, flexible (strips currency / unit
  suffixes, accepts US/EU formats, rejects fractional values for
  integer types), locale, parseStrategy, currency, localeAware.
• Date decoding: iso8601, formatted, flexible (~20 common formats),
  flexibleWithHint, localeAware, custom.
• Bool decoding: standard, flexible (oui/non, ja/nein, …), custom.
• Nested types: flatten(separator:), json(maxBytes: Int = 1 << 20),
  error.

Parsing

• RFC 4180-compliant parser with SIMD-accelerated structural scanning
  (64-byte vectors).
• Single CSVRowStreamProducer powers async, backpressure, and
  progress-reporting decode paths.
• Per-row metadata packed into one [CSVRowView.Field] allocation.
• Fused parse + validate + decode loop avoids materialising the full
  row list.
• Strict mode rejects unterminated quotes, quotes in unquoted fields,
  field-count mismatches, and invalid UTF-8.
• Lenient mode substitutes U+FFFD for invalid UTF-8 and still enforces
  expectedFieldCount when configured.

Errors

• CSVDecodingError and CSVEncodingError carry CSVLocation
  (row / column / coding path) with intelligent suggestions for
  typical mistakes.

Concurrency

• Swift 6.2 strict-concurrency clean; all public types are Sendable.
• BackpressureController cooperates with task cancellation via
  withTaskCancellationHandler.

Platforms

• iOS 18+, macOS 15+, watchOS 11+, tvOS 18+, visionOS 2+.
• Swift 6.2 toolchain.