# YAML Test Matrix

--- &test-G7JE
  Title: Multiline implicit keys
  Tags: [ error, mapping ]

a\nb: 1
c
 d: 1

+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

Line  Col Char Byte Token|Content
   1    0    0    0 +DOC |
   1    0    0    0 +NODE|
   1    0    0    0 +MAP |
   1    0    0    0 +PAIR|
   1    0    0    0 +NODE|
   1    0    0    0 +VAL |
   1    0    0    0 =TEXT|a\x5cnb
   1    4    4    4 -VAL |
   1    4    4    4 -NODE|
   1    4    4    4 =SYNX|:
   1    5    5    5 =WSPC|.
   1    6    6    6 +NODE|
   1    6    6    6 +VAL |
   1    6    6    6 =TEXT|1
   1    7    7    7 -VAL |
   1    7    7    7 -NODE|
   1    7    7    7 =EOL |\x0a
   2    0    8    8 -PAIR|
   2    0    8    8 -MAP |
   2    0    8    8 -NODE|
   2    0    8    8 -DOC |
   2    0    8    8 =ERR |Unexpected.'c'

{
   "a\\nb" : 1,
   "c d" : 1
}

{
  'a\\nb' => 1,
  'c d' => 1
}

stdin:2:1: error: invalid multiline plain key
c
^
 d: 1
~~
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

stdin:2:1: error: invalid multiline plain key
c
^
 d: 1
~~

Parse error: could not find expected ':'
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

-:3:3: (12B): ERROR: ': ' is not a valid token in plain flow (unquoted) scalars
-:3:3:  d: 1  (size=5)
         ^~~  (cols 3-6)

Exception:
yaml-cpp: error at line 3, column 3: illegal map value
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

Unhandled exception. YamlDotNet.Core.SyntaxErrorException: (Line: 3, Col: 3, Idx: 12) - (Line: 3, Col: 3, Idx: 12): While scanning a multiline plain scalar, found invalid mapping.
   at YamlDotNet.Core.Parser.ParseBlockMappingKey(Boolean isFirst)
   at YamlDotNet.Core.Parser.StateMachine()
   at YamlDotNet.Core.Parser.MoveNext()
   at YamlDotNet.RepresentationModel.LibYamlEventStream.WriteTo(TextWriter textWriter)
   at Program.Main(String[] commandLineArguments)
Aborted (core dumped)
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

Unhandled exception. YamlDotNet.Core.SyntaxErrorException: (Line: 3, Col: 3, Idx: 12) - (Line: 3, Col: 3, Idx: 12): While scanning a multiline plain scalar, found invalid mapping.
   at YamlDotNet.Core.Parser.ParseBlockMappingKey(Boolean isFirst)
   at YamlDotNet.Core.Parser.StateMachine()
   at YamlDotNet.Core.Parser.MoveNext()
   at YamlDotNet.Core.ParserExtensions.TryConsume[T](IParser parser, T& event)
   at YamlDotNet.Serialization.NodeDeserializers.ScalarNodeDeserializer.YamlDotNet.Serialization.INodeDeserializer.Deserialize(IParser parser, Type expectedType, Func`3 nestedObjectDeserializer, Object& value)
   at YamlDotNet.Serialization.ValueDeserializers.NodeValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.ValueDeserializers.AliasValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.ValueDeserializers.NodeValueDeserializer.<>c__DisplayClass3_0.<DeserializeValue>b__0(IParser r, Type t)
   at YamlDotNet.Serialization.NodeDeserializers.DictionaryNodeDeserializer.DeserializeHelper(Type tKey, Type tValue, IParser parser, Func`3 nestedObjectDeserializer, IDictionary result)
   at YamlDotNet.Serialization.NodeDeserializers.DictionaryNodeDeserializer.YamlDotNet.Serialization.INodeDeserializer.Deserialize(IParser parser, Type expectedType, Func`3 nestedObjectDeserializer, Object& value)
   at YamlDotNet.Serialization.ValueDeserializers.NodeValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.ValueDeserializers.AliasValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.Deserializer.Deserialize(IParser parser, Type type)
   at YamlDotNet.Serialization.Deserializer.Deserialize(TextReader input, Type type)
   at YamlDotNet.Serialization.Deserializer.Deserialize(TextReader input)
   at Program.Main(String[] commandLineArguments)
Aborted (core dumped)

yaml: line 3: could not find expected ':'

Parsing error near byte offset Pos {posByteOffset = 8, posCharOffset = 8, posLine = 2, posColumn = 0} (Unexpected 'c')
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1
-MAP
-DOC

hsyaml-parser: user error (Unexpected 'c')

/node/node_modules/js-yaml/lib/loader.js:187
  throw generateError(state, message);
  ^
YAMLException: can not read a block mapping entry; a multiline key may not be an implicit key (3:3)

 1 | a\nb: 1
 2 | c
 3 |  d: 1
-------^
    at generateError (/node/node_modules/js-yaml/lib/loader.js:183:10)
    at throwError (/node/node_modules/js-yaml/lib/loader.js:187:9)
    at readBlockMapping (/node/node_modules/js-yaml/lib/loader.js:1145:9)
    at composeNode (/node/node_modules/js-yaml/lib/loader.js:1441:12)
    at readDocument (/node/node_modules/js-yaml/lib/loader.js:1625:3)
    at loadDocuments (/node/node_modules/js-yaml/lib/loader.js:1688:5)
    at Object.loadAll (/node/node_modules/js-yaml/lib/loader.js:1701:19)
    at Object.<anonymous> (/yaml/bin/js-jsyaml-json:7:13)
    at Module._compile (node:internal/modules/cjs/loader:1358:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1416:10) {
  reason: 'can not read a block mapping entry; a multiline key may not be an implicit key',
  mark: {
    name: null,
    buffer: 'a\\nb: 1\nc\n d: 1\n',
    position: 12,
    line: 2,
    column: 2,
    snippet: ' 1 | a\\nb: 1\n 2 | c\n 3 |  d: 1\n-------^'
  }
}

Node.js v20.13.1

Implicit keys need to be on a single line at line 2, column 1:

a\nb: 1
c
^
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

/yaml/bin/js-yaml-json:9
    if (doc.errors.length !== 0) throw doc.errors[0]
                                 ^

YAMLParseError: Implicit keys need to be on a single line at line 2, column 1:

a\nb: 1
c
^

    at Composer.onError (/node/node_modules/yaml/dist/compose/composer.js:69:34)
    at Object.resolveBlockMap (/node/node_modules/yaml/dist/compose/resolve-block-map.js:48:17)
    at resolveCollection (/node/node_modules/yaml/dist/compose/compose-collection.js:13:27)
    at Object.composeCollection (/node/node_modules/yaml/dist/compose/compose-collection.js:47:16)
    at Object.composeNode (/node/node_modules/yaml/dist/compose/compose-node.js:31:38)
    at Object.composeDoc (/node/node_modules/yaml/dist/compose/compose-doc.js:34:23)
    at Composer.next (/node/node_modules/yaml/dist/compose/composer.js:149:40)
    at next (<anonymous>)
    at Composer.compose (/node/node_modules/yaml/dist/compose/composer.js:131:25)
    at compose.next (<anonymous>) {
  code: 'MULTILINE_IMPLICIT_KEY',
  pos: [ 8, 12 ],
  linePos: [ { line: 2, col: 1 }, { line: 3, col: 3 } ]
}

Node.js v20.13.1

luajit: 1:7: could not find expected ':'
stack traceback:
	[C]: in function 'error'
	/usr/local/share/lua/5.1/lyaml/init.lua:306: in function 'error'
	/usr/local/share/lua/5.1/lyaml/init.lua:325: in function 'parse'
	/usr/local/share/lua/5.1/lyaml/init.lua:443: in function 'load_node'
	/usr/local/share/lua/5.1/lyaml/init.lua:340: in function 'load_node'
	/usr/local/share/lua/5.1/lyaml/init.lua:497: in function 'load'
	/yaml/bin/lua-lyaml-json:6: in main chunk
	[C]: at 0x55985c21ded0

/tmp/NimYAML-0.16.0/yaml/stream.nim(134) nimyaml_event
/tmp/NimYAML-0.16.0/yaml/stream.nim(106) next
Error: unhandled exception: Unexpected token (expected ':'): Indentation [YamlStreamError]
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1
=VAL :c

Line      : 2
Column    : 1
Expected  : ALIAS COLON DOC_END DOC_START EOL PLAIN QUESTION QUOTED
Got       : PLAIN_MULTI
Where     : /perl5/lib/perl5/YAML/PP/Parser.pm line 392
YAML      : "c d: 1\n"
  at /yaml/bin/perl-pp-event line 46.
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

Line      : 2
Column    : 1
Expected  : ALIAS COLON DOC_END DOC_START EOL PLAIN QUESTION QUOTED
Got       : PLAIN_MULTI
Where     : /perl5/lib/perl5/YAML/PP/Parser.pm line 392
YAML      : "c d: 1\n"
  at /perl5/lib/perl5/YAML/PP/Loader.pm line 94.

Line      : 2
Column    : 1
Expected  : ALIAS COLON DOC_END DOC_START EOL PLAIN QUESTION QUOTED
Got       : PLAIN_MULTI
Where     : /perl5/lib/perl5/YAML/PP/Parser.pm line 392
YAML      : "c d: 1\n"
  at /perl5/lib/perl5/YAML/PP/Loader.pm line 94.

YAML::PP::LibYAML Error: The problem:

    could not find expected ':'

was found at , line: 3, column: 3
while scanning a simple key at line: 2, column: 1

YAML::PP::LibYAML Error: The problem:

    could not find expected ':'

was found at , line: 3, column: 3
while scanning a simple key at line: 2, column: 1

Parser finished before end of input at /perl5/lib/perl5/YAML/Parser.pm line 4056, <> line 1.

YAML::Tiny failed to classify line 'c' at /yaml/bin/perl-tiny-json line 12.

YAML::Tiny failed to classify line 'c' at /yaml/bin/perl-tiny-perl line 15.

YAML::XS::Load Error: The problem:

    could not find expected ':'

was found at document: 1, line: 3, column: 3
while scanning a simple key at line: 2, column: 1

YAML::XS::Load Error: The problem:

    could not find expected ':'

was found at document: 1, line: 3, column: 3
while scanning a simple key at line: 2, column: 1

YAML Error: Invalid element in map
   Code: YAML_LOAD_ERR_BAD_MAP_ELEMENT
   Line: 2
   Document: 1
 at /perl5/lib/perl5/YAML/Loader.pm line 360.

YAML Error: Invalid element in map
   Code: YAML_LOAD_ERR_BAD_MAP_ELEMENT
   Line: 2
   Document: 1
 at /perl5/lib/perl5/YAML/Loader.pm line 360.

Traceback (most recent call last):
  File "/yaml/bin/py-pyyaml-event", line 7, in <module>
    for event in yaml.parse(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/yaml/__init__.py", line 75, in parse
    while loader.check_event():
          ^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 428, in parse_block_mapping_key
    if self.check_token(KeyToken):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 115, in check_token
    while self.need_more_tokens():
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 152, in need_more_tokens
    self.stale_possible_simple_keys()
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 291, in stale_possible_simple_keys
    raise ScannerError("while scanning a simple key", key.mark,
yaml.scanner.ScannerError: while scanning a simple key
  in "<unicode string>", line 2, column 1:
    c
    ^
could not find expected ':'
  in "<unicode string>", line 3, column 3:
     d: 1
      ^
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

Traceback (most recent call last):
  File "/yaml/bin/py-pyyaml-json", line 19, in <module>
    for doc in yaml.load_all(sys.stdin.read(), Loader=yaml.FullLoader):
  File "/python/lib/python3.12/site-packages/yaml/__init__.py", line 130, in load_all
    yield loader.get_data()
          ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/constructor.py", line 45, in get_data
    return self.construct_document(self.get_node())
                                   ^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 27, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 55, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 127, in compose_mapping_node
    while not self.check_event(MappingEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 428, in parse_block_mapping_key
    if self.check_token(KeyToken):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 115, in check_token
    while self.need_more_tokens():
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 152, in need_more_tokens
    self.stale_possible_simple_keys()
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 291, in stale_possible_simple_keys
    raise ScannerError("while scanning a simple key", key.mark,
yaml.scanner.ScannerError: while scanning a simple key
  in "<unicode string>", line 2, column 1:
    c
    ^
could not find expected ':'
  in "<unicode string>", line 3, column 3:
     d: 1
      ^

Traceback (most recent call last):
  File "/yaml/bin/py-pyyaml-py", line 36, in <module>
    for doc in yaml.load_all(sys.stdin.read(), Loader=yaml.FullLoader):
  File "/python/lib/python3.12/site-packages/yaml/__init__.py", line 130, in load_all
    yield loader.get_data()
          ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/constructor.py", line 45, in get_data
    return self.construct_document(self.get_node())
                                   ^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 27, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 55, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 127, in compose_mapping_node
    while not self.check_event(MappingEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 428, in parse_block_mapping_key
    if self.check_token(KeyToken):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 115, in check_token
    while self.need_more_tokens():
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 152, in need_more_tokens
    self.stale_possible_simple_keys()
  File "/python/lib/python3.12/site-packages/yaml/scanner.py", line 291, in stale_possible_simple_keys
    raise ScannerError("while scanning a simple key", key.mark,
yaml.scanner.ScannerError: while scanning a simple key
  in "<unicode string>", line 2, column 1:
    c
    ^
could not find expected ':'
  in "<unicode string>", line 3, column 3:
     d: 1
      ^

Traceback (most recent call last):
  File "/yaml/bin/py-ruamel-event", line 9, in <module>
    for event in yaml.parse(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/ruamel/yaml/main.py", line 371, in parse
    while parser.check_event():
          ^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 141, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 600, in parse_block_mapping_key
    if self.scanner.check_token(KeyToken):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 169, in check_token
    while self.need_more_tokens():
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 203, in need_more_tokens
    self.stale_possible_simple_keys()
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 348, in stale_possible_simple_keys
    raise ScannerError(
ruamel.yaml.scanner.ScannerError: while scanning a simple key
  in "<unicode string>", line 2, column 1:
    c
    ^ (line: 2)
could not find expected ':'
  in "<unicode string>", line 3, column 3:
     d: 1
      ^ (line: 3)
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1

Traceback (most recent call last):
  File "/yaml/bin/py-ruamel-json", line 21, in <module>
    for doc in yaml.load_all(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/ruamel/yaml/main.py", line 476, in load_all
    yield constructor.get_data()
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 110, in get_data
    return self.construct_document(self.composer.get_node())
                                   ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 63, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 94, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 130, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 204, in compose_mapping_node
    while not self.parser.check_event(MappingEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 141, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 600, in parse_block_mapping_key
    if self.scanner.check_token(KeyToken):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 169, in check_token
    while self.need_more_tokens():
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 203, in need_more_tokens
    self.stale_possible_simple_keys()
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 348, in stale_possible_simple_keys
    raise ScannerError(
ruamel.yaml.scanner.ScannerError: while scanning a simple key
  in "<unicode string>", line 2, column 1:
    c
    ^ (line: 2)
could not find expected ':'
  in "<unicode string>", line 3, column 3:
     d: 1
      ^ (line: 3)

Traceback (most recent call last):
  File "/yaml/bin/py-ruamel-py", line 38, in <module>
    for doc in yaml.load_all(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/ruamel/yaml/main.py", line 476, in load_all
    yield constructor.get_data()
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 110, in get_data
    return self.construct_document(self.composer.get_node())
                                   ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 63, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 94, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 130, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 204, in compose_mapping_node
    while not self.parser.check_event(MappingEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 141, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 600, in parse_block_mapping_key
    if self.scanner.check_token(KeyToken):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 169, in check_token
    while self.need_more_tokens():
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 203, in need_more_tokens
    self.stale_possible_simple_keys()
  File "/python/lib/python3.12/site-packages/ruamel/yaml/scanner.py", line 348, in stale_possible_simple_keys
    raise ScannerError(
ruamel.yaml.scanner.ScannerError: while scanning a simple key
  in "<unicode string>", line 2, column 1:
    c
    ^ (line: 2)
could not find expected ':'
  in "<unicode string>", line 3, column 3:
     d: 1
      ^ (line: 3)

/ruby/gems/psych/lib/psych.rb:458:in `parse': (<unknown>): could not find expected ':' while scanning a simple key at line 2 column 1 (Psych::SyntaxError)
	from /ruby/gems/psych/lib/psych.rb:458:in `parse_stream'
	from /ruby/gems/psych/lib/psych.rb:632:in `load_stream'
	from /yaml/bin/ruby-psych-json:6:in `<main>'

Error: ScanError { mark: Marker { index: 8, line: 2, col: 0 }, info: "while parsing a block mapping, did not find expected key" }
+STR
+DOC
+MAP
=VAL :a\\nb
=VAL :1