diff --git a/Sources/PotentYAML/Cfyaml.swift b/Sources/PotentYAML/Cfyaml.swift
new file mode 100644
index 000000000..3382678a0
--- /dev/null
+++ b/Sources/PotentYAML/Cfyaml.swift
@@ -0,0 +1,138 @@
+//
+//  Cfyaml.swift
+//  PotentCodables
+//
+//  Copyright © 2021 Outfox, inc.
+//
+//
+//  Distributed under the MIT License, See LICENSE for details.
+//
+
+import Cfyaml
+
+
+enum Libfyaml {
+
+  internal static func createParser() -> OpaquePointer? {
+
+    guard let diag = createDiag(options: (FYET_ERROR, false, true)) else {
+      return nil
+    }
+    defer { fy_diag_unref(diag) }
+
+    var parseCfg = fy_parse_cfg(
+      search_path: nil,
+      flags: FYPCF_QUIET,
+      userdata: nil,
+      diag: diag
+    )
+
+    return fy_parser_create(&parseCfg)
+  }
+
+  internal typealias EmitterWriter = (String?) -> Void
+
+  internal typealias EmitterOutput = @convention(c) (
+    OpaquePointer?,
+    fy_emitter_write_type,
+    UnsafePointer<Int8>?,
+    Int32,
+    UnsafeMutableRawPointer?
+  ) -> Int32
+
+  internal static func createEmitter(
+    flags: fy_emitter_cfg_flags,
+    output: EmitterOutput,
+    writer: UnsafePointer<EmitterWriter>
+  ) -> OpaquePointer? {
+
+    guard let diag = createDiag(options: (FYET_ERROR, false, false)) else {
+      return nil
+    }
+    defer { fy_diag_unref(diag) }
+
+    var cfg = fy_emitter_cfg(
+      flags: flags,
+      output: output,
+      userdata: UnsafeMutableRawPointer(mutating: writer),
+      diag: diag
+    )
+
+    return fy_emitter_create(&cfg)
+  }
+
+  internal typealias DiagOptions = (level: fy_error_type, showSource: Bool, showPosition: Bool)
+
+  internal static func createDiag(options: DiagOptions) -> OpaquePointer? {
+
+    var diagCfg = fy_diag_cfg(
+      fp: nil,
+      output_fn: nil,
+      user: nil,
+      level: FYET_ERROR,
+      module_mask: UInt32.max,
+      colorize: false,
+      show_source: options.showSource,
+      show_position: options.showPosition,
+      show_type: false,
+      show_module: false,
+      source_width: Int32.max,
+      position_width: 4,
+      type_width: 0,
+      module_width: 0
+    )
+
+    guard let diag = fy_diag_create(&diagCfg) else {
+      return nil
+    }
+
+    fy_diag_set_collect_errors(diag, true)
+
+    return diag
+  }
+
+
+}
+
+extension fy_emitter_cfg_flags {
+
+  private static var indentMask = Self(UInt32(bitPattern: FYECF_INDENT_MASK))
+  private static var indentShift = Self(UInt32(bitPattern: FYECF_INDENT_SHIFT))
+
+  static func indent<R: RawRepresentable>(_ indent: R) -> Self where R.RawValue == UInt8 {
+    .indent(indent.rawValue)
+  }
+
+  static func indent(_ indent: UInt8) -> Self {
+    precondition(indent >= 0 && indent <= 9)
+    return (Self(UInt32(indent)) & .indentMask) << .indentShift
+  }
+
+  private static var widthMask = Self(UInt32(bitPattern: FYECF_WIDTH_MASK))
+  private static var widthShift = Self(UInt32(bitPattern: FYECF_WIDTH_SHIFT))
+
+  static func width<R: RawRepresentable>(_ width: R) -> Self where R.RawValue == UInt8 {
+    .width(width.rawValue)
+  }
+
+  static func width(_ width: UInt8) -> Self {
+    return (Self(UInt32(width)) & .widthMask) << .widthShift
+  }
+
+  static prefix func ~ (_ value: Self) -> Self {
+    return Self(~value.rawValue)
+  }
+
+  static func & (_ left: Self, _ right: Self) -> Self {
+    return Self(rawValue: left.rawValue & right.rawValue)
+  }
+
+  static func | (_ left: Self, _ right: Self) -> Self {
+    return Self(rawValue: left.rawValue | right.rawValue)
+  }
+
+  static func << (_ left: Self, _ right: Self) -> Self {
+    return Self(rawValue: left.rawValue << right.rawValue)
+  }
+
+}
diff --git a/Sources/PotentYAML/YAMLReader.swift b/Sources/PotentYAML/YAMLReader.swift
index 2971f9193..9a7a98d10 100644
--- a/Sources/PotentYAML/YAMLReader.swift
+++ b/Sources/PotentYAML/YAMLReader.swift
@@ -11,54 +11,28 @@
 import Cfyaml
 import Foundation
 
+
 internal enum YAMLReader {
 
   typealias Error = YAMLSerialization.Error
 
   static func read(data: Data) throws -> YAML.Sequence {
 
-    var diagCfg =
-      fy_diag_cfg(
-        fp: nil,
-        output_fn: nil,
-        user: nil,
-        level: FYET_ERROR,
-        module_mask: UInt32.max,
-        colorize: false,
-        show_source: false,
-        show_position: true,
-        show_type: false,
-        show_module: false,
-        source_width: Int32.max,
-        position_width: 4,
-        type_width: 0,
-        module_width: 0
-      )
-    let diag = fy_diag_create(&diagCfg)
-    fy_diag_set_collect_errors(diag, true)
-    defer { fy_diag_destroy(diag) }
-
-    var parseCfg = fy_parse_cfg(search_path: nil, flags: FYPCF_QUIET, userdata: nil, diag: diag)
-
-    guard let parser = fy_parser_create(&parseCfg).map({ Parser(rawParser: $0, rawDiag: diag) }) else {
+    guard let parser = Libfyaml.createParser().map(Parser.init) else {
       throw Error.unableToCreateParser
     }
-
     defer { parser.destroy() }
 
     return try data.withUnsafeBytes { (ptr: UnsafeRawBufferPointer) in
 
-      let bytes = ptr.bindMemory(to: Int8.self)
-
-      fy_parser_set_string(parser.rawParser, bytes.baseAddress, bytes.count)
+      parser.setInput(ptr.bindMemory(to: CChar.self))
 
-      _ = try parser.expect(eventType: FYET_STREAM_START)
+      try parser.expect(eventType: FYET_STREAM_START)
 
       return try stream(parser: parser)
     }
   }
 
-
   static func stream(parser: Parser) throws -> YAML.Sequence {
 
     var documents: YAML.Sequence = []
@@ -91,7 +65,7 @@ internal enum YAMLReader {
 
     let document = try value(event: root, parser: parser)
 
-    _ = try parser.expect(eventType: FYET_DOCUMENT_END)
+    try parser.expect(eventType: FYET_DOCUMENT_END)
 
     return document
   }
@@ -263,58 +237,72 @@ internal enum YAMLReader {
   struct Parser {
 
     struct Event {
-      let rawEvent: UnsafeMutablePointer<fy_event>
 
-      var type: fy_event_type { rawEvent.pointee.type }
+      let event: UnsafeMutablePointer<fy_event>
+
+      init(_ event: UnsafeMutablePointer<fy_event>) {
+        self.event = event
+      }
+
+      var type: fy_event_type { event.pointee.type }
 
       var anchor: String? {
-        guard let token = rawEvent.pointee.scalar.anchor else { return nil }
+        guard let token = event.pointee.scalar.anchor else { return nil }
         return String(token: token)
       }
 
       var tag: String? {
-        guard let token = rawEvent.pointee.scalar.tag else { return nil }
+        guard let token = event.pointee.scalar.tag else { return nil }
         return String(token: token)
       }
 
       var scalar: (String, fy_scalar_style)? {
-        guard let token = rawEvent.pointee.scalar.value else { return nil }
+        guard let token = event.pointee.scalar.value else { return nil }
         return String(token: token).map { ($0, fy_token_scalar_style(token)) }
       }
 
       var style: fy_node_style {
-        return fy_event_get_node_style(rawEvent)
+        return fy_event_get_node_style(event)
       }
 
     }
 
-    let rawParser: OpaquePointer
-    let rawDiag: OpaquePointer?
+    let parser: OpaquePointer
 
-    func nextIfPresent() -> Event? {
-      return fy_parser_parse(rawParser).map { Event(rawEvent: $0) }
+    func setInput(_ bytes: UnsafeBufferPointer<CChar>) {
+
+      fy_parser_set_string(parser, bytes.baseAddress, bytes.count)
+    }
+
+    private func nextIfPresent() -> Event? {
+
+      return fy_parser_parse(parser).map(Event.init)
     }
 
     func next() throws -> Event {
+
       guard let event = nextIfPresent() else {
         throw error(fallback: .unexpectedEOF)
       }
+
       return event
     }
 
-    func expect(eventType: fy_event_type) throws -> Event {
+    func expect(eventType: fy_event_type) throws {
 
       let event = try next()
+      defer { free(event: event) }
 
       if event.type != eventType {
         throw error(fallback: .unexpectedEvent)
       }
-
-      return event
     }
 
     func error(fallback: Error) -> Error {
-      guard let diag = rawDiag else { return fallback }
+
+      guard let diag = fy_parser_get_diag(parser) else {
+        return fallback
+      }
 
       var prev: UnsafeMutableRawPointer?
       if let error = fy_diag_errors_iterate(diag, &prev) {
@@ -327,11 +315,11 @@ internal enum YAMLReader {
     }
 
     func destroy() {
-      fy_parser_destroy(rawParser)
+      fy_parser_destroy(parser)
     }
 
     func free(event: Event) {
-      fy_parser_event_free(rawParser, event.rawEvent)
+      fy_parser_event_free(parser, event.event)
     }
 
   }
diff --git a/Sources/PotentYAML/YAMLSerialization.swift b/Sources/PotentYAML/YAMLSerialization.swift
index 0198318f4..1c2735343 100644
--- a/Sources/PotentYAML/YAMLSerialization.swift
+++ b/Sources/PotentYAML/YAMLSerialization.swift
@@ -22,7 +22,7 @@ public enum YAMLSerialization {
   /// possible
   public enum Error: Swift.Error {
     case unableToCreateEmitter
-    case emitError
+    case emitError(message: String)
     case unableToCreateParser
     case parserError(message: String, line: Int, column: Int)
     case unexpectedEOF
@@ -74,6 +74,7 @@ public enum YAMLSerialization {
     public static let sortedKeys = WritingOptions(rawValue: 1 << 0)
     public static let pretty = WritingOptions(rawValue: 1 << 1)
     public static let json = WritingOptions(rawValue: 1 << 3)
+    public static let explictDocumentMarkers = WritingOptions(rawValue: 1 << 4)
   }
 
   public static func data(from yaml: YAML,
@@ -102,12 +103,13 @@ public enum YAMLSerialization {
 
     var output = String()
 
-    try YAMLWriter.write([yaml],
-                         preferredStyles: (preferredCollectionStyle, preferredStringStyle),
-                         json: options.contains(.json),
-                         pretty: options.contains(.pretty),
-                         width: options.contains(.pretty) ? .normal : .infinite,
-                         sortedKeys: options.contains(.sortedKeys)) {
+    let writerOptions = YAMLWriter.Options(
+      writingOptions: options,
+      preferredCollectionStyle: preferredCollectionStyle,
+      preferredStringStyle: preferredStringStyle
+    )
+
+    try YAMLWriter.write([yaml], options: writerOptions) {
       guard let str = $0 else { return }
       output.append(str)
     }
@@ -116,3 +118,21 @@ public enum YAMLSerialization {
   }
 
 }
+
+extension YAMLWriter.Options {
+
+  init(
+    writingOptions: YAMLSerialization.WritingOptions,
+    preferredCollectionStyle: YAML.CollectionStyle,
+    preferredStringStyle: YAML.StringStyle
+  ) {
+    self.preferredCollectionStyle = preferredCollectionStyle
+    self.preferredStringStyle = preferredStringStyle
+    self.json = writingOptions.contains(.json)
+    self.pretty = writingOptions.contains(.pretty)
+    self.width = writingOptions.contains(.pretty) ? .normal : .infinite
+    self.sortedKeys = writingOptions.contains(.sortedKeys)
+    self.explicitDocumentMarkers = writingOptions.contains(.explictDocumentMarkers)
+  }
+
+}
diff --git a/Sources/PotentYAML/YAMLWriter.swift b/Sources/PotentYAML/YAMLWriter.swift
index fd14acf81..eb0e62d80 100644
--- a/Sources/PotentYAML/YAMLWriter.swift
+++ b/Sources/PotentYAML/YAMLWriter.swift
@@ -11,126 +11,105 @@
 import Cfyaml
 import Foundation
 
+
 internal struct YAMLWriter {
 
   typealias Error = YAMLSerialization.Error
 
-  typealias Writer = (String?) -> Void
+  enum Width: UInt8 {
+    case normal = 80
+    case wide = 120
+    case infinite = 0xff
+  }
+
+  struct Options {
 
-  enum Width {
-    case normal
-    case wide
-    case infinite
+    static let `default` = Options()
+
+    var preferredCollectionStyle: YAML.CollectionStyle = .any
+    var preferredStringStyle: YAML.StringStyle = .any
+    var json: Bool = false
+    var pretty: Bool = true
+    var width: Width = .normal
+    var sortedKeys: Bool = false
+    var explicitDocumentMarkers: Bool = false
   }
 
   let emitter: OpaquePointer
-  let sortedKeys: Bool
-  let preferredCollectionStyle: YAML.CollectionStyle
-  let preferredStringStyle: YAML.StringStyle
+  let options: Options
+
+  static func write(_ documents: YAML.Sequence, options: Options = .default) throws -> String {
+    var output = ""
+    try write(documents, options: options) { output += $0 ?? "" }
+    return output
+  }
 
   static func write(_ documents: YAML.Sequence,
-                    preferredStyles: (collection: YAML.CollectionStyle, string: YAML.StringStyle) = (.block, .plain),
-                    json: Bool = false,
-                    pretty: Bool = true,
-                    width: Width = .normal,
-                    sortedKeys: Bool = false,
-                    writer: @escaping Writer) throws {
-
-    func output(
-      emitter: OpaquePointer?,
-      writeType: fy_emitter_write_type,
-      str: UnsafePointer<Int8>?,
-      len: Int32,
-      userInfo: UnsafeMutableRawPointer?
-    ) -> Int32 {
-      guard let writer = userInfo?.assumingMemoryBound(to: Writer.self).pointee else {
-        fatalError()
-      }
-      guard let str = str else {
-        writer(nil)
-        return 0
-      }
-      let strPtr = UnsafeMutableRawPointer(mutating: str)
-      writer(String(bytesNoCopy: strPtr, length: Int(len), encoding: .utf8, freeWhenDone: false))
-      return len
-    }
+                    options: Options = Options(),
+                    writer: @escaping Libfyaml.EmitterWriter) throws {
 
     try withUnsafePointer(to: writer) { writerPtr in
 
-      var flags =
-        switch (pretty, json) {
-        case (true, true): FYECF_MODE_JSON.rawValue
-        case (true, false): FYECF_MODE_PRETTY.rawValue
-        case (false, true): FYECF_MODE_JSON_ONELINE.rawValue
-        default: FYECF_DEFAULT.rawValue
-        }
-
-      switch width {
-      case .normal:
-        flags |= FYECF_WIDTH_80.rawValue
-      case .wide:
-        flags |= FYECF_WIDTH_132.rawValue
-      case .infinite:
-        flags |= FYECF_WIDTH_INF.rawValue
+      var flags: fy_emitter_cfg_flags
+      switch (options.pretty, options.json, options.width) {
+      case (true, true, let width):
+        flags = FYECF_MODE_JSON | .width(width)
+      case (true, false, let width):
+        flags = FYECF_MODE_PRETTY | .width(width)
+      case (false, true, let width):
+        flags = FYECF_MODE_JSON_ONELINE | .width(width)
+      case (false, false, let width):
+        flags = FYECF_MODE_ORIGINAL | FYECF_INDENT_DEFAULT | .width(width)
       }
 
-      var emitterCfg = fy_emitter_cfg(
-        flags: fy_emitter_cfg_flags(rawValue: flags),
-        output: output,
-        userdata: UnsafeMutableRawPointer(mutating: writerPtr),
-        diag: nil
-      )
-
-      guard let emitter = fy_emitter_create(&emitterCfg) else {
+      guard let emitter = Libfyaml.createEmitter(flags: flags, output: emitOutput, writer: writerPtr) else {
         throw Error.unableToCreateEmitter
       }
       defer { fy_emitter_destroy(emitter) }
 
-      let writer = YAMLWriter(
-        emitter: emitter,
-        sortedKeys: sortedKeys,
-        preferredCollectionStyle: preferredStyles.collection,
-        preferredStringStyle: preferredStyles.string
-      )
-
-      return try writer.emit(documents: documents)
+      return try YAMLWriter(emitter: emitter, options: options)
+        .emit(documents: documents)
     }
   }
 
   private func emit(documents: [YAML]) throws {
 
-    emit(type: FYET_STREAM_START)
+    let implicitDocumentMarkers = !options.explicitDocumentMarkers && documents.count == 1 ? 1 : 0
+
+    try emit(type: FYET_STREAM_START)
 
     for document in documents {
-      emit(type: FYET_DOCUMENT_START, args: 0, 0, 0)
+      try emit(type: FYET_DOCUMENT_START, args: implicitDocumentMarkers, 0, 0)
 
       try emit(value: document)
 
-      emit(type: FYET_DOCUMENT_END)
+      try emit(type: FYET_DOCUMENT_END, args: implicitDocumentMarkers)
     }
 
-    emit(type: FYET_STREAM_END)
+    try emit(type: FYET_STREAM_END)
+
+    try failIfError()
   }
 
   private func emit(value: YAML) throws {
 
     switch value {
     case .null(anchor: let anchor):
-      emit(scalar: "null", style: FYSS_PLAIN, anchor: anchor, tag: nil)
+      try emit(scalar: "null", style: FYSS_PLAIN, anchor: anchor, tag: nil)
 
     case .string(let string, style: let style, tag: let tag, anchor: let anchor):
-      let stringStyle = style != .any ? style : preferredStringStyle
+      let stringStyle = style != .any ? style : options.preferredStringStyle
       let scalarStyle =  fy_scalar_style(rawValue: stringStyle.rawValue)
-      emit(scalar: string, style: scalarStyle, anchor: anchor, tag: tag?.rawValue)
+      try emit(scalar: string, style: scalarStyle, anchor: anchor, tag: tag?.rawValue)
 
     case .integer(let integer, anchor: let anchor):
-      emit(scalar: integer.value, style: FYSS_PLAIN, anchor: anchor, tag: nil)
+      try emit(scalar: integer.value, style: FYSS_PLAIN, anchor: anchor, tag: nil)
 
     case .float(let float, anchor: let anchor):
-      emit(scalar: float.value, style: FYSS_PLAIN, anchor: anchor, tag: nil)
+      try emit(scalar: float.value, style: FYSS_PLAIN, anchor: anchor, tag: nil)
 
     case .bool(let bool, anchor: let anchor):
-      emit(scalar: bool ? "true" : "false", style: FYSS_PLAIN, anchor: anchor, tag: nil)
+      try emit(scalar: bool ? "true" : "false", style: FYSS_PLAIN, anchor: anchor, tag: nil)
 
     case .sequence(let sequence, style: let style, tag: let tag, anchor: let anchor):
       try emit(sequence: sequence, style: style, anchor: anchor, tag: tag)
@@ -139,20 +118,20 @@ internal struct YAMLWriter {
       try emit(mapping: mapping, style: style, anchor: anchor, tag: tag)
 
     case .alias(let alias):
-      emit(alias: alias)
+      try emit(alias: alias)
 
     }
   }
 
   private func emit(mapping: YAML.Mapping, style: YAML.CollectionStyle, anchor: String?, tag: YAML.Tag?) throws {
-    emit(
+    try emit(
       type: FYET_MAPPING_START,
-      args: style.nodeStyle(preferred: preferredCollectionStyle).rawValue,
+      args: style.nodeStyle(preferred: options.preferredCollectionStyle).rawValue,
       anchor.varArg,
       (tag?.rawValue).varArg
     )
     var mapping = mapping
-    if sortedKeys {
+    if options.sortedKeys {
       mapping = mapping.sorted {
         $0.key.description < $1.key.description
       }
@@ -161,61 +140,93 @@ internal struct YAMLWriter {
       try emit(value: entry.key)
       try emit(value: entry.value)
     }
-    emit(type: FYET_MAPPING_END)
+    try emit(type: FYET_MAPPING_END)
   }
 
   private func emit(sequence: [YAML], style: YAML.CollectionStyle, anchor: String?, tag: YAML.Tag?) throws {
-    emit(
+    try emit(
       type: FYET_SEQUENCE_START,
-      args: style.nodeStyle(preferred: preferredCollectionStyle).rawValue,
+      args: style.nodeStyle(preferred: options.preferredCollectionStyle).rawValue,
       anchor.varArg,
       (tag?.rawValue).varArg
     )
     try sequence.forEach { element in
       try emit(value: element)
     }
-    emit(type: FYET_SEQUENCE_END)
+    try emit(type: FYET_SEQUENCE_END)
   }
 
-  private func emit(
-    scalar: String,
-    style: fy_scalar_style,
-    anchor: String?,
-    tag: String?
-  ) {
-    scalar.withCString { scalarPtr in
-      anchor.withCString { anchorPtr in
-        tag.withCString { tagPtr in
-          emit(type: FYET_SCALAR, args: style.rawValue, scalarPtr, FY_NT, anchorPtr, tagPtr)
+  private func emit(scalar: String, style: fy_scalar_style, anchor: String?, tag: String?) throws {
+    try scalar.withCString { scalarPtr in
+      try anchor.withCString { anchorPtr in
+        try tag.withCString { tagPtr in
+          try emit(type: FYET_SCALAR, args: style.rawValue, scalarPtr, FY_NT, anchorPtr, tagPtr)
         }
       }
     }
   }
 
-  private func emit(
-    alias: String
-  ) {
-    alias.withCString { aliasPtr in
-      emit(type: FYET_ALIAS, args: aliasPtr)
+  private func emit(alias: String) throws {
+    try alias.withCString { aliasPtr in
+      try emit(type: FYET_ALIAS, args: aliasPtr)
     }
   }
 
-  private func emit(type: fy_event_type, args: CVarArg...) {
-    withVaList(args) { valist in
-      let event = fy_emit_event_vcreate(emitter, type, valist)
-      fy_emit_event(emitter, event)
+  private func emit(type: fy_event_type, args: CVarArg...) throws {
+    let res = withVaList(args) { valist in
+      fy_emit_vevent(emitter, type, valist)
+    }
+    if res == -1 {
+      throw error()
     }
   }
 
+  private func failIfError() throws {
+
+    guard fy_diag_got_error(fy_emitter_get_diag(emitter)) else {
+      return
+    }
+
+    throw error()
+  }
+
+  private func error() -> Error {
+    if let diag = fy_emitter_get_diag(emitter) {
+
+      var prev: UnsafeMutableRawPointer?
+      if let error = fy_diag_errors_iterate(diag, &prev) {
+
+        return Error.emitError(message: String(cString: error.pointee.msg))
+      }
+    }
+
+    return .emitError(message: "Unknown emitter error")
+  }
+
+  private static let emitOutput: Libfyaml.EmitterOutput = { _, _, str, len, userInfo in
+
+    guard let writer = userInfo?.assumingMemoryBound(to: Libfyaml.EmitterWriter.self).pointee else {
+      fatalError()
+    }
+
+    guard let str = str else {
+      writer(nil)
+      return 0
+    }
+
+    let strPtr = UnsafeMutableRawPointer(mutating: str)
+    writer(String(bytesNoCopy: strPtr, length: Int(len), encoding: .utf8, freeWhenDone: false))
+    return len
+  }
 }
 
+
 extension Optional where Wrapped: CVarArg {
 
   var varArg: CVarArg { self ?? unsafeBitCast(0, to: OpaquePointer.self) }
 
 }
 
-
 extension Optional where Wrapped == String {
 
   func withCString<Result>(_ body: (UnsafePointer<Int8>) throws -> Result) rethrows -> Result {
@@ -229,6 +240,7 @@ extension Optional where Wrapped == String {
 
 }
 
+
 extension YAML.CollectionStyle {
 
   func nodeStyle(preferred: Self) -> fy_node_style {
diff --git a/Tests/YAMLAnyValueTests.swift b/Tests/YAMLAnyValueTests.swift
index 01fad6ff2..7d3d32111 100644
--- a/Tests/YAMLAnyValueTests.swift
+++ b/Tests/YAMLAnyValueTests.swift
@@ -104,7 +104,6 @@ class YAMLAnyValueTests: XCTestCase {
 
     let yaml =
     """
-    ---
     nil: null
     bool: true
     string: Hello World!
@@ -147,7 +146,6 @@ class YAMLAnyValueTests: XCTestCase {
       1: b
       4: c
       3: d
-    ...
 
     """
 
diff --git a/Tests/YAMLEncoderTests.swift b/Tests/YAMLEncoderTests.swift
index b9ad72ffd..c7b784cef 100644
--- a/Tests/YAMLEncoderTests.swift
+++ b/Tests/YAMLEncoderTests.swift
@@ -25,9 +25,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     camelCased: Hello World!
-    ...
 
     """
 
@@ -45,9 +43,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     snake_cased: Hello World!
-    ...
 
     """
 
@@ -65,9 +61,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     kebab-cased: Hello World!
-    ...
 
     """
 
@@ -88,10 +82,8 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: 5
     string: Hello World!
-    ...
 
     """
 
@@ -109,11 +101,9 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     a: 2
     b: 3
     c: 1
-    ...
 
     """
 
@@ -133,10 +123,8 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: 5
     string: Hello World!
-    ...
 
     """
 
@@ -154,11 +142,9 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     a: 2
     b: 3
     c: 1
-    ...
 
     """
 
@@ -184,7 +170,6 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     b: 5
     d: Hello World!
     a: true
@@ -196,7 +181,6 @@ class YAMLEncoderTests: XCTestCase {
         b: 5
         d: Hello World!
         a: true
-    ...
 
     """
 
@@ -217,9 +201,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     date: \(parsedDate.iso8601EncodedString())
-    ...
 
     """
 
@@ -240,9 +222,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     date: \(date.timeIntervalSince1970)
-    ...
 
     """
 
@@ -263,9 +243,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     date: \(date.timeIntervalSince1970 * 1000.0)
-    ...
 
     """
 
@@ -286,9 +264,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     date: \(date.timeIntervalSinceReferenceDate)
-    ...
 
     """
 
@@ -312,9 +288,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     date: \(formatter.string(from: date))
-    ...
 
     """
 
@@ -338,9 +312,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     date: \(date.timeIntervalSinceReferenceDate)
-    ...
 
     """
 
@@ -367,9 +339,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     date: {}
-    ...
 
     """
 
@@ -392,9 +362,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     data: \(data.base64EncodedString())
-    ...
 
     """
 
@@ -415,10 +383,8 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     data:
     \(data.map { "- \($0)" }.joined(separator: "\n"))
-    ...
 
     """
 
@@ -439,9 +405,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     data: \(data.hexEncodedString())
-    ...
 
     """
 
@@ -465,9 +429,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     data: {}
-    ...
 
     """
 
@@ -489,9 +451,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     bigInt: \(bigInt)
-    ...
 
     """
 
@@ -509,9 +469,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     bigInt: \(bigInt)
-    ...
 
     """
 
@@ -529,9 +487,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     bigUInt: \(bigUInt)
-    ...
 
     """
 
@@ -549,9 +505,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     dec: \(dec)
-    ...
 
     """
 
@@ -569,9 +523,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     dec: \(dec)
-    ...
 
     """
 
@@ -589,9 +541,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     dec: .nan
-    ...
 
     """
 
@@ -609,9 +559,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     double: \(double)
-    ...
 
     """
 
@@ -629,9 +577,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     double: \(double)
-    ...
 
     """
 
@@ -649,9 +595,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     double: .nan
-    ...
 
     """
 
@@ -669,9 +613,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     double: +.inf
-    ...
 
     """
 
@@ -689,9 +631,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     double: -.inf
-    ...
 
     """
 
@@ -709,9 +649,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: \(float)
-    ...
 
     """
 
@@ -729,9 +667,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: \(float)
-    ...
 
     """
 
@@ -749,9 +685,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: .nan
-    ...
 
     """
 
@@ -769,9 +703,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: +.inf
-    ...
 
     """
 
@@ -789,9 +721,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: -.inf
-    ...
 
     """
 
@@ -809,9 +739,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: \(float)
-    ...
 
     """
 
@@ -829,9 +757,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: \(float)
-    ...
 
     """
 
@@ -849,9 +775,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: .nan
-    ...
 
     """
 
@@ -869,9 +793,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: +.inf
-    ...
 
     """
 
@@ -889,9 +811,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     float: -.inf
-    ...
 
     """
 
@@ -909,9 +829,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -929,9 +847,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -949,9 +865,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -969,9 +883,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -989,9 +901,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -1009,9 +919,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -1029,9 +937,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -1049,9 +955,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -1069,9 +973,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -1089,9 +991,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     int: \(int)
-    ...
 
     """
 
@@ -1109,9 +1009,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     uint: \(uint)
-    ...
 
     """
 
@@ -1129,9 +1027,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     uint: \(uint)
-    ...
 
     """
 
@@ -1149,9 +1045,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     uint: \(uint)
-    ...
 
     """
 
@@ -1169,9 +1063,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     uint: \(uint)
-    ...
 
     """
 
@@ -1189,9 +1081,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     uint: \(uint)
-    ...
 
     """
 
@@ -1209,9 +1099,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     url: \(url.absoluteString)
-    ...
 
     """
 
@@ -1229,9 +1117,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     uuid: \(uuid.uuidString)
-    ...
 
     """
 
@@ -1252,9 +1138,7 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     null: null
-    ...
 
     """
 
@@ -1268,12 +1152,10 @@ class YAMLEncoderTests: XCTestCase {
 
     let yaml =
     """
-    ---
     b: 1
     z: 2
     n: 3
     f: 4
-    ...
 
     """
 
diff --git a/Tests/YAMLErrorTests.swift b/Tests/YAMLErrorTests.swift
new file mode 100644
index 000000000..e62464621
--- /dev/null
+++ b/Tests/YAMLErrorTests.swift
@@ -0,0 +1,98 @@
+//
+//  YAMLErrorTests.swift
+//  PotentCodables
+//
+//  Copyright © 2019 Outfox, inc.
+//
+//
+//  Distributed under the MIT License, See LICENSE for details.
+//
+
+import Foundation
+import PotentYAML
+import XCTest
+
+
+/// Tests covering *fixed* errors in libfyaml or its usage.
+///
+class YAMLErrorTests: XCTestCase {
+  public func testSimpleScalarNotOnDocMarkerLinePretty() throws {
+
+    let scalarYaml1: YAML = "simple"
+    XCTAssertEqual(
+      try YAMLSerialization.string(from: scalarYaml1, options: [.pretty]),
+      #"""
+      ---
+      simple
+      ...
+
+      """#
+    )
+  }
+
+  public func testSimpleScalarNotOnDocMarkerLineExplicit() throws {
+
+    let scalarYaml1: YAML = "simple"
+    XCTAssertEqual(
+      try YAMLSerialization.string(from: scalarYaml1, options: [.explictDocumentMarkers]),
+      #"""
+      ---
+      simple
+      ...
+
+      """#
+    )
+  }
+
+  public func testSimpleScalarNoDocMarkers() throws {
+
+    let scalarYaml1: YAML = "simple"
+    XCTAssertEqual(
+      try YAMLSerialization.string(from: scalarYaml1, options: []),
+      #"""
+      simple
+
+      """#
+    )
+  }
+
+  public func testOutputWhitespaceOnlyString() throws {
+
+    let scalarYaml1: YAML = .string(.init(repeating: " ", count: 1))
+    XCTAssertEqual(
+      try YAMLSerialization.string(from: scalarYaml1),
+      #"""
+      " "
+
+      """#
+    )
+
+    let scalarYaml2: YAML = .string(.init(repeating: " ", count: 2))
+    XCTAssertEqual(
+      try YAMLSerialization.string(from: scalarYaml2),
+      #"""
+      "  "
+
+      """#
+    )
+
+    let scalarYaml3: YAML = .string(.init(repeating: " ", count: 3))
+    XCTAssertEqual(
+      try YAMLSerialization.string(from: scalarYaml3),
+      #"""
+      "   "
+
+      """#
+    )
+
+    let scalarYaml9: YAML = .string(.init(repeating: " ", count: 9))
+    XCTAssertEqual(
+      try YAMLSerialization.string(from: scalarYaml9),
+      #"""
+      "         "
+
+      """#
+    )
+  }
+
+}
diff --git a/Tests/YAMLOrderTests.swift b/Tests/YAMLOrderTests.swift
index 695fe1e24..8bcca0732 100644
--- a/Tests/YAMLOrderTests.swift
+++ b/Tests/YAMLOrderTests.swift
@@ -28,11 +28,9 @@ class YAMLOrderTests: XCTestCase {
     XCTAssertEqual(
       yaml.description,
       """
-      ---
       c: 1
       a: 2
       b: 3
-      ...
 
       """
     )
@@ -49,11 +47,9 @@ class YAMLOrderTests: XCTestCase {
     XCTAssertEqual(
       yaml.description,
       """
-      ---
       a: 2
       b: 3
       c: 1
-      ...
 
       """
     )
@@ -93,11 +89,9 @@ class YAMLOrderTests: XCTestCase {
     XCTAssertEqual(
       yaml.description,
       """
-      ---
       c: 1
       a: 2
       b: 3
-      ...
 
       """
     )
diff --git a/Tests/YAMLTests.swift b/Tests/YAMLTests.swift
index 2815c863e..916c5d51a 100644
--- a/Tests/YAMLTests.swift
+++ b/Tests/YAMLTests.swift
@@ -165,11 +165,9 @@ class YAMLTests: XCTestCase {
     XCTAssertEqual(
       yaml,
       """
-      ---
       c: 1
       a: 2
       b: 3
-      ...
 
       """
     )
@@ -186,11 +184,9 @@ class YAMLTests: XCTestCase {
     XCTAssertEqual(
       yaml,
       """
-      ---
       a: 2
       b: 3
       c: 1
-      ...
 
       """
     )
@@ -214,7 +210,7 @@ class YAMLTests: XCTestCase {
 
       """
 
-    XCTAssertEqual(object, try YAMLSerialization.yaml(from: yaml.data(using: .utf8)!))
+    XCTAssertEqual(object, try YAMLSerialization.yaml(from: yaml))
   }
 
   func testDescriptionOrder() throws {
@@ -228,11 +224,9 @@ class YAMLTests: XCTestCase {
     XCTAssertEqual(
       yaml.description,
       """
-      ---
       c: 1
       a: 2
       b: 3
-      ...
 
       """
     )
@@ -280,9 +274,7 @@ class YAMLTests: XCTestCase {
     XCTAssertEqual(
       try YAMLSerialization.string(from: ["plain": "This should be output plain"]),
       #"""
-      ---
       plain: This should be output plain
-      ...
 
       """#
     )
@@ -291,9 +283,7 @@ class YAMLTests: XCTestCase {
       try YAMLSerialization.string(from: ["dquoted": "This should be output dquoted"],
                                    preferredStringStyle: .doubleQuoted),
       #"""
-      ---
       "dquoted": "This should be output dquoted"
-      ...
 
       """#
     )
@@ -302,9 +292,7 @@ class YAMLTests: XCTestCase {
       try YAMLSerialization.string(from: ["squoted": "This should be output squoted"],
                                    preferredStringStyle: .singleQuoted),
       #"""
-      ---
       'squoted': 'This should be output squoted'
-      ...
 
       """#
     )
@@ -313,9 +301,7 @@ class YAMLTests: XCTestCase {
       try YAMLSerialization.string(from: [.string("plain", style: .plain): "This should be output squoted"],
                                    preferredStringStyle: .singleQuoted),
       #"""
-      ---
       plain: 'This should be output squoted'
-      ...
 
       """#
     )
@@ -327,9 +313,7 @@ class YAMLTests: XCTestCase {
     XCTAssertEqual(
       try YAMLSerialization.string(from: ["block": "This should be output block"]),
       #"""
-      ---
       block: This should be output block
-      ...
 
       """#
     )
@@ -338,11 +322,9 @@ class YAMLTests: XCTestCase {
       try YAMLSerialization.string(from: ["flow": "This should be output flow"],
                                    preferredCollectionStyle: .flow),
       #"""
-      ---
       {
         'flow': 'This should be output flow'
       }
-      ...
 
       """#
     )
@@ -352,9 +334,7 @@ class YAMLTests: XCTestCase {
         .string(from: .mapping([.init(key: "block", value: "This should be output block")], style: .block),
                 preferredCollectionStyle: .flow),
       #"""
-      ---
       block: This should be output block
-      ...
 
       """#
     )
diff --git a/Tests/YAMLWriterTests.swift b/Tests/YAMLWriterTests.swift
index 2d2d5c06e..e42b7b1bf 100644
--- a/Tests/YAMLWriterTests.swift
+++ b/Tests/YAMLWriterTests.swift
@@ -15,33 +15,200 @@ import XCTest
 
 class YAMLWriterTests: XCTestCase {
 
-  func testWriteMultipleDocuments() throws {
+  func testWriteScalarCompact() throws {
+
+    let options = YAMLWriter.Options(pretty: false)
+
+    XCTAssertEqual(
+      try YAMLWriter.write(["simple"], options: options),
+      """
+      simple
+
+      """
+    )
+
+  }
+
+  func testWriteScalarExplicitDocumentMarkers() throws {
 
-    var output = ""
-    try YAMLWriter.write([.bool(true), .integer(123)]) { output += $0 ?? "" }
+    let options = YAMLWriter.Options(pretty: false, explicitDocumentMarkers: true)
 
     XCTAssertEqual(
-      output,
+      try YAMLWriter.write(["simple"], options: options),
       """
-      --- true
+      ---
+      simple
       ...
-      --- 123
+
+      """
+    )
+
+  }
+
+  func testWriteScalarPretty() throws {
+
+    let options = YAMLWriter.Options(pretty: true)
+
+    XCTAssertEqual(
+      try YAMLWriter.write(["simple"], options: options),
+      """
+      ---
+      simple
       ...
 
       """
     )
+
   }
 
-  func testWriteAliases() throws {
+  func testWriteStringPreferPlain() throws {
+
+    let options = YAMLWriter.Options(preferredStringStyle: .plain, pretty: false)
+
+    XCTAssertEqual(
+      try YAMLWriter.write(["simple\nstring"], options: options),
+      """
+      simple
+
+      string
+
+      """
+    )
+
+  }
+
+  func testWriteStringPreferSingleQuoted() throws {
+
+    let options = YAMLWriter.Options(preferredStringStyle: .singleQuoted, pretty: false)
+
+    XCTAssertEqual(
+      try YAMLWriter.write(["simple\nstring"], options: options),
+      """
+      'simple
+
+      string'
+
+      """
+    )
+
+  }
+
+  func testWriteStringPreferDoubleQuoted() throws {
+
+    let options = YAMLWriter.Options(preferredStringStyle: .doubleQuoted, pretty: false)
+
+    XCTAssertEqual(
+      try YAMLWriter.write(["simple\nstring"], options: options),
+      """
+      "simple\\nstring"
+
+      """
+    )
+
+  }
+
+  func testWriteStringPreferLiteral() throws {
+
+    let options = YAMLWriter.Options(preferredStringStyle: .literal, pretty: false)
+
+    XCTAssertEqual(
+      try YAMLWriter.write(["simple\nstring"], options: options),
+      """
+      |-
+        simple
+        string
+
+      """
+    )
+
+  }
+
+  func testWriteStringPreferFolded() throws {
+
+    let options = YAMLWriter.Options(preferredStringStyle: .folded, pretty: false)
+
+    XCTAssertEqual(
+      try YAMLWriter.write(["simple\nstring"], options: options),
+      """
+      >-
+        simple
+        \
+
+        string
+
+      """
+    )
+
+  }
+
+  func testWriteWidthNormal() throws {
+
+    let yamlVal: YAML =
+      "Long Text 123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 1234567890"
+
+    let options = YAMLWriter.Options(width: .normal)
+    let yamlStr = try YAMLWriter.write([yamlVal], options: options)
 
     XCTAssertEqual(
-      try YAMLSerialization.string(from: .alias("num")),
+      yamlStr,
       """
-      --- *num
+      ---
+      Long Text 123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789
+      1234567890
       ...
 
       """
     )
+
+    XCTAssertEqual(try YAMLReader.read(data: Data(yamlStr.utf8)).first, yamlVal)
+  }
+
+  func testWriteWidthNormalInBlock() throws {
+
+    let yamlVal: YAML = [
+      "a": "Long Text 123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 1234567890"
+    ]
+
+    let options = YAMLWriter.Options(preferredCollectionStyle: .block, width: .normal)
+    let yamlStr = try YAMLWriter.write([yamlVal], options: options)
+
+    XCTAssertEqual(
+      yamlStr,
+      """
+      a: Long Text 123456789 123456789 123456789 123456789 123456789 123456789 123456789
+        123456789 1234567890
+
+      """
+    )
+
+    XCTAssertEqual(try YAMLReader.read(data: Data(yamlStr.utf8)).first, yamlVal)
+  }
+
+  func testWriteMultipleDocuments() throws {
+
+    XCTAssertEqual(
+      try YAMLWriter.write([.bool(true), .integer(123)]),
+      """
+      ---
+      true
+      ...
+      ---
+      123
+      ...
+
+      """
+    )
+  }
+
+  func testWriteAliases() throws {
+
+    XCTAssertEqual(
+      try YAMLWriter.write([.alias("num")]),
+      """
+      *num
+
+      """
+    )
   }
 
 }