(boolean_scalar) @boolean
(null_scalar) @constant.builtin

[
  (double_quote_scalar)
  (single_quote_scalar)
  (block_scalar)
  (string_scalar)
] @string

(escape_sequence) @string.escape

[
  (integer_scalar)
  (float_scalar)
] @number

(comment) @comment

[
  (anchor_name)
  (alias_name)
  (tag) 
] @type

key: (flow_node (plain_scalar (string_scalar) @property)) 

[
 ","
 "-"
 ":"
 ">"
 "?"
 "|"
] @punctuation.delimiter

[
 "["
 "]"
 "{"
 "}"
] @punctuation.bracket

[
 "*"
 "&"
 "---"
 "..."
] @punctuation.special