Nim/lib/pure/json.nim

#
#
#            Nim's Runtime Library
#        (c) Copyright 2015 Andreas Rumpf, Dominik Picheta
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

## This module implements a simple high performance `JSON`:idx:
## parser. JSON (JavaScript Object Notation) is a lightweight
## data-interchange format that is easy for humans to read and write
## (unlike XML). It is easy for machines to parse and generate.
## JSON is based on a subset of the JavaScript Programming Language,
## Standard ECMA-262 3rd Edition - December 1999.
##
## Overview
## ========
##
## Parsing JSON
## ------------
##
## JSON often arrives into your program (via an API or a file) as a ``string``.
## The first step is to change it from its serialized form into a nested object
## structure called a ``JsonNode``.
##
## The ``parseJson`` procedure takes a string containing JSON and returns a
## ``JsonNode`` object. This is an object variant and it is either a
## ``JObject``, ``JArray``, ``JString``, ``JInt``, ``JFloat``, ``JBool`` or
## ``JNull``. You check the kind of this object variant by using the ``kind``
## accessor.
##
## For a ``JsonNode`` who's kind is ``JObject``, you can access its fields using
## the ``[]`` operator. The following example shows how to do this:
##
## .. code-block:: Nim
##   import json
##
##   let jsonNode = parseJson("""{"key": 3.14}""")
##
##   doAssert jsonNode.kind == JObject
##   doAssert jsonNode["key"].kind == JFloat
##
## Reading values
## --------------
##
## Once you have a ``JsonNode``, retrieving the values can then be achieved
## by using one of the helper procedures, which include:
##
## * ``getInt``
## * ``getFloat``
## * ``getStr``
## * ``getBool``
##
## To retrieve the value of ``"key"`` you can do the following:
##
## .. code-block:: Nim
##   import json
##
##   let jsonNode = parseJson("""{"key": 3.14}""")
##
##   doAssert jsonNode["key"].getFloat() == 3.14
##
## **Important:** The ``[]`` operator will raise an exception when the
## specified field does not exist.
##
## Handling optional keys
## ----------------------
##
## By using the ``{}`` operator instead of ``[]``, it will return ``nil``
## when the field is not found. The ``get``-family of procedures will return a
## type's default value when called on ``nil``.
##
## .. code-block:: Nim
##   import json
##
##   let jsonNode = parseJson("{}")
##
##   doAssert jsonNode{"nope"}.getInt() == 0
##   doAssert jsonNode{"nope"}.getFloat() == 0
##   doAssert jsonNode{"nope"}.getStr() == ""
##   doAssert jsonNode{"nope"}.getBool() == false
##
## Using default values
## --------------------
##
## The ``get``-family helpers also accept an additional parameter which allow
## you to fallback to a default value should the key's values be ``null``:
##
## .. code-block:: Nim
##   import json
##
##   let jsonNode = parseJson("""{"key": 3.14, "key2": null}""")
##
##   doAssert jsonNode["key"].getFloat(6.28) == 3.14
##   doAssert jsonNode["key2"].getFloat(3.14) == 3.14
##   doAssert jsonNode{"nope"}.getFloat(3.14) == 3.14 # note the {}
##
## Unmarshalling
## -------------
##
## In addition to reading dynamic data, Nim can also unmarshal JSON directly
## into a type with the ``to`` macro.
##
## .. code-block:: Nim
##   import json
##
##   type
##     User = object
##       name: string
##       age: int
##
##   let userJson = parseJson("""{ "name": "Nim", "age": 12 }""")
##   let user = to(userJson, User)
##
## Creating JSON
## =============
##
## This module can also be used to comfortably create JSON using the ``%*``
## operator:
##
## .. code-block:: nim
##   import json
##
##   var hisName = "John"
##   let herAge = 31
##   var j = %*
##     [
##       { "name": hisName, "age": 30 },
##       { "name": "Susan", "age": herAge }
##     ]
##
##   var j2 = %* {"name": "Isaac", "books": ["Robot Dreams"]}
##   j2["details"] = %* {"age":35, "pi":3.1415}
##   echo j2

runnableExamples:
  ## Note: for JObject, key ordering is preserved, unlike in some languages,
  ## this is convenient for some use cases. Example:
  type Foo = object
    a1, a2, a0, a3, a4: int
  doAssert $(%* Foo()) == """{"a1":0,"a2":0,"a0":0,"a3":0,"a4":0}"""

import
  hashes, tables, strutils, lexbase, streams, macros, parsejson,
  options

export
  tables.`$`

export
  parsejson.JsonEventKind, parsejson.JsonError, JsonParser, JsonKindError,
  open, close, str, getInt, getFloat, kind, getColumn, getLine, getFilename,
  errorMsg, errorMsgExpected, next, JsonParsingError, raiseParseErr

type
  JsonNodeKind* = enum ## possible JSON node types
    JNull,
    JBool,
    JInt,
    JFloat,
    JString,
    JObject,
    JArray

  JsonNode* = ref JsonNodeObj ## JSON node
  JsonNodeObj* {.acyclic.} = object
    case kind*: JsonNodeKind
    of JString:
      str*: string
    of JInt:
      num*: BiggestInt
    of JFloat:
      fnum*: float
    of JBool:
      bval*: bool
    of JNull:
      nil
    of JObject:
      fields*: OrderedTable[string, JsonNode]
    of JArray:
      elems*: seq[JsonNode]

proc newJString*(s: string): JsonNode =
  ## Creates a new `JString JsonNode`.
  result = JsonNode(kind: JString, str: s)

proc newJStringMove(s: string): JsonNode =
  result = JsonNode(kind: JString)
  shallowCopy(result.str, s)

proc newJInt*(n: BiggestInt): JsonNode =
  ## Creates a new `JInt JsonNode`.
  result = JsonNode(kind: JInt, num: n)

proc newJFloat*(n: float): JsonNode =
  ## Creates a new `JFloat JsonNode`.
  result = JsonNode(kind: JFloat, fnum: n)

proc newJBool*(b: bool): JsonNode =
  ## Creates a new `JBool JsonNode`.
  result = JsonNode(kind: JBool, bval: b)

proc newJNull*(): JsonNode =
  ## Creates a new `JNull JsonNode`.
  result = JsonNode(kind: JNull)

proc newJObject*(): JsonNode =
  ## Creates a new `JObject JsonNode`
  result = JsonNode(kind: JObject, fields: initOrderedTable[string, JsonNode](4))

proc newJArray*(): JsonNode =
  ## Creates a new `JArray JsonNode`
  result = JsonNode(kind: JArray, elems: @[])

proc getStr*(n: JsonNode, default: string = ""): string =
  ## Retrieves the string value of a `JString JsonNode`.
  ##
  ## Returns ``default`` if ``n`` is not a ``JString``, or if ``n`` is nil.
  if n.isNil or n.kind != JString: return default
  else: return n.str

proc getInt*(n: JsonNode, default: int = 0): int =
  ## Retrieves the int value of a `JInt JsonNode`.
  ##
  ## Returns ``default`` if ``n`` is not a ``JInt``, or if ``n`` is nil.
  if n.isNil or n.kind != JInt: return default
  else: return int(n.num)

proc getBiggestInt*(n: JsonNode, default: BiggestInt = 0): BiggestInt =
  ## Retrieves the BiggestInt value of a `JInt JsonNode`.
  ##
  ## Returns ``default`` if ``n`` is not a ``JInt``, or if ``n`` is nil.
  if n.isNil or n.kind != JInt: return default
  else: return n.num

proc getFloat*(n: JsonNode, default: float = 0.0): float =
  ## Retrieves the float value of a `JFloat JsonNode`.
  ##
  ## Returns ``default`` if ``n`` is not a ``JFloat`` or ``JInt``, or if ``n`` is nil.
  if n.isNil: return default
  case n.kind
  of JFloat: return n.fnum
  of JInt: return float(n.num)
  else: return default

proc getBool*(n: JsonNode, default: bool = false): bool =
  ## Retrieves the bool value of a `JBool JsonNode`.
  ##
  ## Returns ``default`` if ``n`` is not a ``JBool``, or if ``n`` is nil.
  if n.isNil or n.kind != JBool: return default
  else: return n.bval

proc getFields*(n: JsonNode,
    default = initOrderedTable[string, JsonNode](4)):
        OrderedTable[string, JsonNode] =
  ## Retrieves the key, value pairs of a `JObject JsonNode`.
  ##
  ## Returns ``default`` if ``n`` is not a ``JObject``, or if ``n`` is nil.
  if n.isNil or n.kind != JObject: return default
  else: return n.fields

proc getElems*(n: JsonNode, default: seq[JsonNode] = @[]): seq[JsonNode] =
  ## Retrieves the array of a `JArray JsonNode`.
  ##
  ## Returns ``default`` if ``n`` is not a ``JArray``, or if ``n`` is nil.
  if n.isNil or n.kind != JArray: return default
  else: return n.elems

proc add*(father, child: JsonNode) =
  ## Adds `child` to a JArray node `father`.
  assert father.kind == JArray
  father.elems.add(child)

proc add*(obj: JsonNode, key: string, val: JsonNode) =
  ## Sets a field from a `JObject`.
  assert obj.kind == JObject
  obj.fields[key] = val

proc `%`*(s: string): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JString JsonNode`.
  result = JsonNode(kind: JString, str: s)

proc `%`*(n: uint): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JInt JsonNode`.
  result = JsonNode(kind: JInt, num: BiggestInt(n))

proc `%`*(n: int): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JInt JsonNode`.
  result = JsonNode(kind: JInt, num: n)

proc `%`*(n: BiggestUInt): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JInt JsonNode`.
  result = JsonNode(kind: JInt, num: BiggestInt(n))

proc `%`*(n: BiggestInt): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JInt JsonNode`.
  result = JsonNode(kind: JInt, num: n)

proc `%`*(n: float): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JFloat JsonNode`.
  result = JsonNode(kind: JFloat, fnum: n)

proc `%`*(b: bool): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JBool JsonNode`.
  result = JsonNode(kind: JBool, bval: b)

proc `%`*(keyVals: openArray[tuple[key: string, val: JsonNode]]): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JObject JsonNode`
  if keyVals.len == 0: return newJArray()
  result = newJObject()
  for key, val in items(keyVals): result.fields[key] = val

template `%`*(j: JsonNode): JsonNode = j

proc `%`*[T](elements: openArray[T]): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JArray JsonNode`
  result = newJArray()
  for elem in elements: result.add(%elem)

proc `%`*[T](table: Table[string, T]|OrderedTable[string, T]): JsonNode =
  ## Generic constructor for JSON data. Creates a new ``JObject JsonNode``.
  result = newJObject()
  for k, v in table: result[k] = %v

proc `%`*[T](opt: Option[T]): JsonNode =
  ## Generic constructor for JSON data. Creates a new ``JNull JsonNode``
  ## if ``opt`` is empty, otherwise it delegates to the underlying value.
  if opt.isSome: %opt.get else: newJNull()

when false:
  # For 'consistency' we could do this, but that only pushes people further
  # into that evil comfort zone where they can use Nim without understanding it
  # causing problems later on.
  proc `%`*(elements: set[bool]): JsonNode =
    ## Generic constructor for JSON data. Creates a new `JObject JsonNode`.
    ## This can only be used with the empty set ``{}`` and is supported
    ## to prevent the gotcha ``%*{}`` which used to produce an empty
    ## JSON array.
    result = newJObject()
    assert false notin elements, "usage error: only empty sets allowed"
    assert true notin elements, "usage error: only empty sets allowed"

proc `[]=`*(obj: JsonNode, key: string, val: JsonNode) {.inline.} =
  ## Sets a field from a `JObject`.
  assert(obj.kind == JObject)
  obj.fields[key] = val

proc `%`*[T: object](o: T): JsonNode =
  ## Construct JsonNode from tuples and objects.
  result = newJObject()
  for k, v in o.fieldPairs: result[k] = %v

proc `%`*(o: ref object): JsonNode =
  ## Generic constructor for JSON data. Creates a new `JObject JsonNode`
  if o.isNil:
    result = newJNull()
  else:
    result = %(o[])

proc `%`*(o: enum): JsonNode =
  ## Construct a JsonNode that represents the specified enum value as a
  ## string. Creates a new ``JString JsonNode``.
  result = %($o)

proc toJson(x: NimNode): NimNode {.compileTime.} =
  case x.kind
  of nnkBracket: # array
    if x.len == 0: return newCall(bindSym"newJArray")
    result = newNimNode(nnkBracket)
    for i in 0 ..< x.len:
      result.add(toJson(x[i]))
    result = newCall(bindSym("%", brOpen), result)
  of nnkTableConstr: # object
    if x.len == 0: return newCall(bindSym"newJObject")
    result = newNimNode(nnkTableConstr)
    for i in 0 ..< x.len:
      x[i].expectKind nnkExprColonExpr
      result.add newTree(nnkExprColonExpr, x[i][0], toJson(x[i][1]))
    result = newCall(bindSym("%", brOpen), result)
  of nnkCurly: # empty object
    x.expectLen(0)
    result = newCall(bindSym"newJObject")
  of nnkNilLit:
    result = newCall(bindSym"newJNull")
  of nnkPar:
    if x.len == 1: result = toJson(x[0])
    else: result = newCall(bindSym("%", brOpen), x)
  else:
    result = newCall(bindSym("%", brOpen), x)

macro `%*`*(x: untyped): untyped =
  ## Convert an expression to a JsonNode directly, without having to specify
  ## `%` for every element.
  result = toJson(x)

proc `==`*(a, b: JsonNode): bool =
  ## Check two nodes for equality
  if a.isNil:
    if b.isNil: return true
    return false
  elif b.isNil or a.kind != b.kind:
    return false
  else:
    case a.kind
    of JString:
      result = a.str == b.str
    of JInt:
      result = a.num == b.num
    of JFloat:
      result = a.fnum == b.fnum
    of JBool:
      result = a.bval == b.bval
    of JNull:
      result = true
    of JArray:
      result = a.elems == b.elems
    of JObject:
      # we cannot use OrderedTable's equality here as
      # the order does not matter for equality here.
      if a.fields.len != b.fields.len: return false
      for key, val in a.fields:
        if not b.fields.hasKey(key): return false
        if b.fields[key] != val: return false
      result = true

proc hash*(n: OrderedTable[string, JsonNode]): Hash {.noSideEffect.}

proc hash*(n: JsonNode): Hash =
  ## Compute the hash for a JSON node
  case n.kind
  of JArray:
    result = hash(n.elems)
  of JObject:
    result = hash(n.fields)
  of JInt:
    result = hash(n.num)
  of JFloat:
    result = hash(n.fnum)
  of JBool:
    result = hash(n.bval.int)
  of JString:
    result = hash(n.str)
  of JNull:
    result = Hash(0)

proc hash*(n: OrderedTable[string, JsonNode]): Hash =
  for key, val in n:
    result = result xor (hash(key) !& hash(val))
  result = !$result

proc len*(n: JsonNode): int =
  ## If `n` is a `JArray`, it returns the number of elements.
  ## If `n` is a `JObject`, it returns the number of pairs.
  ## Else it returns 0.
  case n.kind
  of JArray: result = n.elems.len
  of JObject: result = n.fields.len
  else: discard

proc `[]`*(node: JsonNode, name: string): JsonNode {.inline.} =
  ## Gets a field from a `JObject`, which must not be nil.
  ## If the value at `name` does not exist, raises KeyError.
  assert(not isNil(node))
  assert(node.kind == JObject)
  when defined(nimJsonGet):
    if not node.fields.hasKey(name): return nil
  result = node.fields[name]

proc `[]`*(node: JsonNode, index: int): JsonNode {.inline.} =
  ## Gets the node at `index` in an Array. Result is undefined if `index`
  ## is out of bounds, but as long as array bound checks are enabled it will
  ## result in an exception.
  assert(not isNil(node))
  assert(node.kind == JArray)
  return node.elems[index]

proc hasKey*(node: JsonNode, key: string): bool =
  ## Checks if `key` exists in `node`.
  assert(node.kind == JObject)
  result = node.fields.hasKey(key)

proc contains*(node: JsonNode, key: string): bool =
  ## Checks if `key` exists in `node`.
  assert(node.kind == JObject)
  node.fields.hasKey(key)

proc contains*(node: JsonNode, val: JsonNode): bool =
  ## Checks if `val` exists in array `node`.
  assert(node.kind == JArray)
  find(node.elems, val) >= 0

proc `{}`*(node: JsonNode, keys: varargs[string]): JsonNode =
  ## Traverses the node and gets the given value. If any of the
  ## keys do not exist, returns ``nil``. Also returns ``nil`` if one of the
  ## intermediate data structures is not an object.
  ##
  ## This proc can be used to create tree structures on the
  ## fly (sometimes called `autovivification`:idx:):
  ##
  ## .. code-block:: nim
  ##   myjson{"parent", "child", "grandchild"} = newJInt(1)
  ##
  result = node
  for key in keys:
    if isNil(result) or result.kind != JObject:
      return nil
    result = result.fields.getOrDefault(key)

proc `{}`*(node: JsonNode, index: varargs[int]): JsonNode =
  ## Traverses the node and gets the given value. If any of the
  ## indexes do not exist, returns ``nil``. Also returns ``nil`` if one of the
  ## intermediate data structures is not an array.
  result = node
  for i in index:
    if isNil(result) or result.kind != JArray or i >= node.len:
      return nil
    result = result.elems[i]

proc getOrDefault*(node: JsonNode, key: string): JsonNode =
  ## Gets a field from a `node`. If `node` is nil or not an object or
  ## value at `key` does not exist, returns nil
  if not isNil(node) and node.kind == JObject:
    result = node.fields.getOrDefault(key)

template simpleGetOrDefault*{`{}`(node, [key])}(node: JsonNode,
    key: string): JsonNode = node.getOrDefault(key)

proc `{}=`*(node: JsonNode, keys: varargs[string], value: JsonNode) =
  ## Traverses the node and tries to set the value at the given location
  ## to ``value``. If any of the keys are missing, they are added.
  var node = node
  for i in 0..(keys.len-2):
    if not node.hasKey(keys[i]):
      node[keys[i]] = newJObject()
    node = node[keys[i]]
  node[keys[keys.len-1]] = value

proc delete*(obj: JsonNode, key: string) =
  ## Deletes ``obj[key]``.
  assert(obj.kind == JObject)
  if not obj.fields.hasKey(key):
    raise newException(KeyError, "key not in object")
  obj.fields.del(key)

proc copy*(p: JsonNode): JsonNode =
  ## Performs a deep copy of `a`.
  case p.kind
  of JString:
    result = newJString(p.str)
  of JInt:
    result = newJInt(p.num)
  of JFloat:
    result = newJFloat(p.fnum)
  of JBool:
    result = newJBool(p.bval)
  of JNull:
    result = newJNull()
  of JObject:
    result = newJObject()
    for key, val in pairs(p.fields):
      result.fields[key] = copy(val)
  of JArray:
    result = newJArray()
    for i in items(p.elems):
      result.elems.add(copy(i))

# ------------- pretty printing ----------------------------------------------

proc indent(s: var string, i: int) =
  s.add(spaces(i))

proc newIndent(curr, indent: int, ml: bool): int =
  if ml: return curr + indent
  else: return indent

proc nl(s: var string, ml: bool) =
  s.add(if ml: "\n" else: " ")

proc escapeJsonUnquoted*(s: string; result: var string) =
  ## Converts a string `s` to its JSON representation without quotes.
  ## Appends to ``result``.
  for c in s:
    case c
    of '\L': result.add("\\n")
    of '\b': result.add("\\b")
    of '\f': result.add("\\f")
    of '\t': result.add("\\t")
    of '\v': result.add("\\v")
    of '\r': result.add("\\r")
    of '"': result.add("\\\"")
    of '\0'..'\7': result.add("\\u000" & $ord(c))
    of '\14'..'\31': result.add("\\u00" & toHex(ord(c), 2))
    of '\\': result.add("\\\\")
    else: result.add(c)

proc escapeJsonUnquoted*(s: string): string =
  ## Converts a string `s` to its JSON representation without quotes.
  result = newStringOfCap(s.len + s.len shr 3)
  escapeJsonUnquoted(s, result)

proc escapeJson*(s: string; result: var string) =
  ## Converts a string `s` to its JSON representation with quotes.
  ## Appends to ``result``.
  result.add("\"")
  escapeJsonUnquoted(s, result)
  result.add("\"")

proc escapeJson*(s: string): string =
  ## Converts a string `s` to its JSON representation with quotes.
  result = newStringOfCap(s.len + s.len shr 3)
  escapeJson(s, result)

proc toPretty(result: var string, node: JsonNode, indent = 2, ml = true,
              lstArr = false, currIndent = 0) =
  case node.kind
  of JObject:
    if lstArr: result.indent(currIndent) # Indentation
    if node.fields.len > 0:
      result.add("{")
      result.nl(ml) # New line
      var i = 0
      for key, val in pairs(node.fields):
        if i > 0:
          result.add(",")
          result.nl(ml) # New Line
        inc i
        # Need to indent more than {
        result.indent(newIndent(currIndent, indent, ml))
        escapeJson(key, result)
        result.add(": ")
        toPretty(result, val, indent, ml, false,
                 newIndent(currIndent, indent, ml))
      result.nl(ml)
      result.indent(currIndent) # indent the same as {
      result.add("}")
    else:
      result.add("{}")
  of JString:
    if lstArr: result.indent(currIndent)
    escapeJson(node.str, result)
  of JInt:
    if lstArr: result.indent(currIndent)
    when defined(js): result.add($node.num)
    else: result.addInt(node.num)
  of JFloat:
    if lstArr: result.indent(currIndent)
    # Fixme: implement new system.add ops for the JS target
    when defined(js): result.add($node.fnum)
    else: result.addFloat(node.fnum)
  of JBool:
    if lstArr: result.indent(currIndent)
    result.add(if node.bval: "true" else: "false")
  of JArray:
    if lstArr: result.indent(currIndent)
    if len(node.elems) != 0:
      result.add("[")
      result.nl(ml)
      for i in 0..len(node.elems)-1:
        if i > 0:
          result.add(",")
          result.nl(ml) # New Line
        toPretty(result, node.elems[i], indent, ml,
            true, newIndent(currIndent, indent, ml))
      result.nl(ml)
      result.indent(currIndent)
      result.add("]")
    else: result.add("[]")
  of JNull:
    if lstArr: result.indent(currIndent)
    result.add("null")

proc pretty*(node: JsonNode, indent = 2): string =
  ## Returns a JSON Representation of `node`, with indentation and
  ## on multiple lines.
  ##
  ## Similar to prettyprint in Python.
  runnableExamples:
    let j = %* {"name": "Isaac", "books": ["Robot Dreams"],
                "details": {"age": 35, "pi": 3.1415}}
    doAssert pretty(j) == """
{
  "name": "Isaac",
  "books": [
    "Robot Dreams"
  ],
  "details": {
    "age": 35,
    "pi": 3.1415
  }
}"""
  result = ""
  toPretty(result, node, indent)

proc toUgly*(result: var string, node: JsonNode) =
  ## Converts `node` to its JSON Representation, without
  ## regard for human readability. Meant to improve ``$`` string
  ## conversion performance.
  ##
  ## JSON representation is stored in the passed `result`
  ##
  ## This provides higher efficiency than the ``pretty`` procedure as it
  ## does **not** attempt to format the resulting JSON to make it human readable.
  var comma = false
  case node.kind:
  of JArray:
    result.add "["
    for child in node.elems:
      if comma: result.add ","
      else: comma = true
      result.toUgly child
    result.add "]"
  of JObject:
    result.add "{"
    for key, value in pairs(node.fields):
      if comma: result.add ","
      else: comma = true
      key.escapeJson(result)
      result.add ":"
      result.toUgly value
    result.add "}"
  of JString:
    node.str.escapeJson(result)
  of JInt:
    when defined(js): result.add($node.num)
    else: result.addInt(node.num)
  of JFloat:
    when defined(js): result.add($node.fnum)
    else: result.addFloat(node.fnum)
  of JBool:
    result.add(if node.bval: "true" else: "false")
  of JNull:
    result.add "null"

proc `$`*(node: JsonNode): string =
  ## Converts `node` to its JSON Representation on one line.
  result = newStringOfCap(node.len shl 1)
  toUgly(result, node)

iterator items*(node: JsonNode): JsonNode =
  ## Iterator for the items of `node`. `node` has to be a JArray.
  assert node.kind == JArray
  for i in items(node.elems):
    yield i

iterator mitems*(node: var JsonNode): var JsonNode =
  ## Iterator for the items of `node`. `node` has to be a JArray. Items can be
  ## modified.
  assert node.kind == JArray
  for i in mitems(node.elems):
    yield i

iterator pairs*(node: JsonNode): tuple[key: string, val: JsonNode] =
  ## Iterator for the child elements of `node`. `node` has to be a JObject.
  assert node.kind == JObject
  for key, val in pairs(node.fields):
    yield (key, val)

iterator keys*(node: JsonNode): string =
  ## Iterator for the keys in `node`. `node` has to be a JObject.
  assert node.kind == JObject
  for key in node.fields.keys:
    yield key

iterator mpairs*(node: var JsonNode): tuple[key: string, val: var JsonNode] =
  ## Iterator for the child elements of `node`. `node` has to be a JObject.
  ## Values can be modified
  assert node.kind == JObject
  for key, val in mpairs(node.fields):
    yield (key, val)

proc parseJson(p: var JsonParser): JsonNode =
  ## Parses JSON from a JSON Parser `p`.
  case p.tok
  of tkString:
    # we capture 'p.a' here, so we need to give it a fresh buffer afterwards:
    result = newJStringMove(p.a)
    p.a = ""
    discard getTok(p)
  of tkInt:
    result = newJInt(parseBiggestInt(p.a))
    discard getTok(p)
  of tkFloat:
    result = newJFloat(parseFloat(p.a))
    discard getTok(p)
  of tkTrue:
    result = newJBool(true)
    discard getTok(p)
  of tkFalse:
    result = newJBool(false)
    discard getTok(p)
  of tkNull:
    result = newJNull()
    discard getTok(p)
  of tkCurlyLe:
    result = newJObject()
    discard getTok(p)
    while p.tok != tkCurlyRi:
      if p.tok != tkString:
        raiseParseErr(p, "string literal as key")
      var key = p.a
      discard getTok(p)
      eat(p, tkColon)
      var val = parseJson(p)
      result[key] = val
      if p.tok != tkComma: break
      discard getTok(p)
    eat(p, tkCurlyRi)
  of tkBracketLe:
    result = newJArray()
    discard getTok(p)
    while p.tok != tkBracketRi:
      result.add(parseJson(p))
      if p.tok != tkComma: break
      discard getTok(p)
    eat(p, tkBracketRi)
  of tkError, tkCurlyRi, tkBracketRi, tkColon, tkComma, tkEof:
    raiseParseErr(p, "{")

iterator parseJsonFragments*(s: Stream, filename: string = ""): JsonNode =
  ## Parses from a stream `s` into `JsonNodes`. `filename` is only needed
  ## for nice error messages.
  ## The JSON fragments are separated by whitespace. This can be substantially
  ## faster than the comparable loop
  ## ``for x in splitWhitespace(s): yield parseJson(x)``.
  ## This closes the stream `s` after it's done.
  var p: JsonParser
  p.open(s, filename)
  try:
    discard getTok(p) # read first token
    while p.tok != tkEof:
      yield p.parseJson()
  finally:
    p.close()

proc parseJson*(s: Stream, filename: string = ""): JsonNode =
  ## Parses from a stream `s` into a `JsonNode`. `filename` is only needed
  ## for nice error messages.
  ## If `s` contains extra data, it will raise `JsonParsingError`.
  ## This closes the stream `s` after it's done.
  var p: JsonParser
  p.open(s, filename)
  try:
    discard getTok(p) # read first token
    result = p.parseJson()
    eat(p, tkEof) # check if there is no extra data
  finally:
    p.close()

when defined(js):
  from math import `mod`
  type
    JSObject = object

  proc parseNativeJson(x: cstring): JSObject {.importc: "JSON.parse".}

  proc getVarType(x: JSObject): JsonNodeKind =
    result = JNull
    proc getProtoName(y: JSObject): cstring
      {.importc: "Object.prototype.toString.call".}
    case $getProtoName(x) # TODO: Implicit returns fail here.
    of "[object Array]": return JArray
    of "[object Object]": return JObject
    of "[object Number]":
      if cast[float](x) mod 1.0 == 0:
        return JInt
      else:
        return JFloat
    of "[object Boolean]": return JBool
    of "[object Null]": return JNull
    of "[object String]": return JString
    else: assert false

  proc len(x: JSObject): int =
    assert x.getVarType == JArray
    asm """
      `result` = `x`.length;
    """

  proc `[]`(x: JSObject, y: string): JSObject =
    assert x.getVarType == JObject
    asm """
      `result` = `x`[`y`];
    """

  proc `[]`(x: JSObject, y: int): JSObject =
    assert x.getVarType == JArray
    asm """
      `result` = `x`[`y`];
    """

  proc convertObject(x: JSObject): JsonNode =
    case getVarType(x)
    of JArray:
      result = newJArray()
      for i in 0 ..< x.len:
        result.add(x[i].convertObject())
    of JObject:
      result = newJObject()
      asm """for (var property in `x`) {
        if (`x`.hasOwnProperty(property)) {
      """
      var nimProperty: cstring
      var nimValue: JSObject
      asm "`nimProperty` = property; `nimValue` = `x`[property];"
      result[$nimProperty] = nimValue.convertObject()
      asm "}}"
    of JInt:
      result = newJInt(cast[int](x))
    of JFloat:
      result = newJFloat(cast[float](x))
    of JString:
      result = newJString($cast[cstring](x))
    of JBool:
      result = newJBool(cast[bool](x))
    of JNull:
      result = newJNull()

  proc parseJson*(buffer: string): JsonNode =
    when nimvm:
      return parseJson(newStringStream(buffer), "input")
    else:
      return parseNativeJson(buffer).convertObject()

else:
  proc parseJson*(buffer: string): JsonNode =
    ## Parses JSON from `buffer`.
    ## If `buffer` contains extra data, it will raise `JsonParsingError`.
    result = parseJson(newStringStream(buffer), "input")

  proc parseFile*(filename: string): JsonNode =
    ## Parses `file` into a `JsonNode`.
    ## If `file` contains extra data, it will raise `JsonParsingError`.
    var stream = newFileStream(filename, fmRead)
    if stream == nil:
      raise newException(IOError, "cannot read from file: " & filename)
    result = parseJson(stream, filename)

# -- Json deserialiser. --

template verifyJsonKind(node: JsonNode, kinds: set[JsonNodeKind],
                        ast: string) =
  if node == nil:
    raise newException(KeyError, "key not found: " & ast)
  elif  node.kind notin kinds:
    let msg = "Incorrect JSON kind. Wanted '$1' in '$2' but got '$3'." % [
      $kinds,
      ast,
      $node.kind
    ]
    raise newException(JsonKindError, msg)

when defined(nimFixedForwardGeneric):

  macro isRefSkipDistinct(arg: typed): untyped =
    var impl = getTypeImpl(arg)
    if impl.kind == nnkBracketExpr and impl[0].eqIdent("typeDesc"):
      impl = getTypeImpl(impl[1])
    while impl.kind == nnkDistinctTy:
      impl = getTypeImpl(impl[0])
    result = newLit(impl.kind == nnkRefTy)

  # The following forward declarations don't work in older versions of Nim

  # forward declare all initFromJson

  proc initFromJson(dst: var string; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson(dst: var bool; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson(dst: var JsonNode; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T: SomeInteger](dst: var T; jsonNode: JsonNode, jsonPath: var string)
  proc initFromJson[T: SomeFloat](dst: var T; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T: enum](dst: var T; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T](dst: var seq[T]; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[S,T](dst: var array[S,T]; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T](dst: var Table[string,T];jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T](dst: var OrderedTable[string,T];jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T](dst: var ref T; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T](dst: var Option[T]; jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T: distinct](dst: var T;jsonNode: JsonNode; jsonPath: var string)
  proc initFromJson[T: object|tuple](dst: var T; jsonNode: JsonNode; jsonPath: var string)

  # initFromJson definitions

  proc initFromJson(dst: var string; jsonNode: JsonNode; jsonPath: var string) =
    verifyJsonKind(jsonNode, {JString, JNull}, jsonPath)
    # since strings don't have a nil state anymore, this mapping of
    # JNull to the default string is questionable. `none(string)` and
    # `some("")` have the same potentional json value `JNull`.
    if jsonNode.kind == JNull:
      dst = ""
    else:
      dst = jsonNode.str

  proc initFromJson(dst: var bool; jsonNode: JsonNode; jsonPath: var string) =
    verifyJsonKind(jsonNode, {JBool}, jsonPath)
    dst = jsonNode.bval

  proc initFromJson(dst: var JsonNode; jsonNode: JsonNode; jsonPath: var string) =
    dst = jsonNode.copy

  proc initFromJson[T: SomeInteger](dst: var T; jsonNode: JsonNode, jsonPath: var string) =
    verifyJsonKind(jsonNode, {JInt}, jsonPath)
    dst = T(jsonNode.num)

  proc initFromJson[T: SomeFloat](dst: var T; jsonNode: JsonNode; jsonPath: var string) =
    verifyJsonKind(jsonNode, {JInt, JFloat}, jsonPath)
    if jsonNode.kind == JFloat:
      dst = T(jsonNode.fnum)
    else:
      dst = T(jsonNode.num)

  proc initFromJson[T: enum](dst: var T; jsonNode: JsonNode; jsonPath: var string) =
    verifyJsonKind(jsonNode, {JString}, jsonPath)
    dst = parseEnum[T](jsonNode.getStr)

  proc initFromJson[T](dst: var seq[T]; jsonNode: JsonNode; jsonPath: var string) =
    verifyJsonKind(jsonNode, {JArray}, jsonPath)
    dst.setLen jsonNode.len
    let orignalJsonPathLen = jsonPath.len
    for i in 0 ..< jsonNode.len:
      jsonPath.add '['
      jsonPath.addInt i
      jsonPath.add ']'
      initFromJson(dst[i], jsonNode[i], jsonPath)
      jsonPath.setLen orignalJsonPathLen

  proc initFromJson[S,T](dst: var array[S,T]; jsonNode: JsonNode; jsonPath: var string) =
    verifyJsonKind(jsonNode, {JArray}, jsonPath)
    let originalJsonPathLen = jsonPath.len
    for i in 0 ..< jsonNode.len:
      jsonPath.add '['
      jsonPath.addInt i
      jsonPath.add ']'
      initFromJson(dst[i], jsonNode[i], jsonPath)
      jsonPath.setLen originalJsonPathLen

  proc initFromJson[T](dst: var Table[string,T];jsonNode: JsonNode; jsonPath: var string) =
    dst = initTable[string, T]()
    verifyJsonKind(jsonNode, {JObject}, jsonPath)
    let originalJsonPathLen = jsonPath.len
    for key in keys(jsonNode.fields):
      jsonPath.add '.'
      jsonPath.add key
      initFromJson(mgetOrPut(dst, key, default(T)), jsonNode[key], jsonPath)
      jsonPath.setLen originalJsonPathLen

  proc initFromJson[T](dst: var OrderedTable[string,T];jsonNode: JsonNode; jsonPath: var string) =
    dst = initOrderedTable[string,T]()
    verifyJsonKind(jsonNode, {JObject}, jsonPath)
    let originalJsonPathLen = jsonPath.len
    for key in keys(jsonNode.fields):
      jsonPath.add '.'
      jsonPath.add key
      initFromJson(mgetOrPut(dst, key, default(T)), jsonNode[key], jsonPath)
      jsonPath.setLen originalJsonPathLen

  proc initFromJson[T](dst: var ref T; jsonNode: JsonNode; jsonPath: var string) =
    verifyJsonKind(jsonNode, {JObject, JNull}, jsonPath)
    if jsonNode.kind == JNull:
      dst = nil
    else:
      dst = new(T)
      initFromJson(dst[], jsonNode, jsonPath)

  proc initFromJson[T](dst: var Option[T]; jsonNode: JsonNode; jsonPath: var string) =
    if jsonNode != nil and jsonNode.kind != JNull:
      dst = some(default(T))
      initFromJson(dst.get, jsonNode, jsonPath)

  macro assignDistinctImpl[T : distinct](dst: var T;jsonNode: JsonNode; jsonPath: var string) =
    let typInst = getTypeInst(dst)
    let typImpl = getTypeImpl(dst)
    let baseTyp = typImpl[0]

    result = quote do:
      when nimvm:
        # workaround #12282
        var tmp: `baseTyp`
        initFromJson( tmp, `jsonNode`, `jsonPath`)
        `dst` = `typInst`(tmp)
      else:
        initFromJson( `baseTyp`(`dst`), `jsonNode`, `jsonPath`)

  proc initFromJson[T : distinct](dst: var T; jsonNode: JsonNode; jsonPath: var string) =
    assignDistinctImpl(dst, jsonNode, jsonPath)

  proc detectIncompatibleType(typeExpr, lineinfoNode: NimNode): void =
    if typeExpr.kind == nnkTupleConstr:
      error("Use a named tuple instead of: " & typeExpr.repr, lineinfoNode)

  proc foldObjectBody(dst, typeNode, tmpSym, jsonNode, jsonPath, originalJsonPathLen: NimNode): void {.compileTime.} =
    case typeNode.kind
    of nnkEmpty:
      discard
    of nnkRecList, nnkTupleTy:
      for it in typeNode:
        foldObjectBody(dst, it, tmpSym, jsonNode, jsonPath, originalJsonPathLen)

    of nnkIdentDefs:
      typeNode.expectLen 3
      let fieldSym = typeNode[0]
      let fieldNameLit = newLit(fieldSym.strVal)
      let fieldPathLit = newLit("." & fieldSym.strVal)
      let fieldType = typeNode[1]

      # Detecting incompatiple tuple types in `assignObjectImpl` only
      # would be much cleaner, but the ast for tuple types does not
      # contain usable type information.
      detectIncompatibleType(fieldType, fieldSym)

      dst.add quote do:
        jsonPath.add `fieldPathLit`
        when nimvm:
          when isRefSkipDistinct(`tmpSym`.`fieldSym`):
            # workaround #12489
            var tmp: `fieldType`
            initFromJson(tmp, getOrDefault(`jsonNode`,`fieldNameLit`), `jsonPath`)
            `tmpSym`.`fieldSym` = tmp
          else:
            initFromJson(`tmpSym`.`fieldSym`, getOrDefault(`jsonNode`,`fieldNameLit`), `jsonPath`)
        else:
          initFromJson(`tmpSym`.`fieldSym`, getOrDefault(`jsonNode`,`fieldNameLit`), `jsonPath`)
        jsonPath.setLen `originalJsonPathLen`

    of nnkRecCase:
      let kindSym = typeNode[0][0]
      let kindNameLit = newLit(kindSym.strVal)
      let kindPathLit = newLit("." & kindSym.strVal)
      let kindType = typeNode[0][1]
      let kindOffsetLit = newLit(uint(getOffset(kindSym)))
      dst.add quote do:
        var kindTmp: `kindType`
        jsonPath.add `kindPathLit`
        initFromJson(kindTmp, `jsonNode`[`kindNameLit`], `jsonPath`)
        jsonPath.setLen `originalJsonPathLen`
        when defined js:
          `tmpSym`.`kindSym` = kindTmp
        else:
          when nimvm:
            `tmpSym`.`kindSym` = kindTmp
          else:
            # fuck it, assign kind field anyway
            ((cast[ptr `kindType`](cast[uint](`tmpSym`.addr) + `kindOffsetLit`))[]) = kindTmp
      dst.add nnkCaseStmt.newTree(nnkDotExpr.newTree(tmpSym, kindSym))
      for i in 1 ..< typeNode.len:
        foldObjectBody(dst, typeNode[i], tmpSym, jsonNode, jsonPath, originalJsonPathLen)

    of nnkOfBranch, nnkElse:
      let ofBranch = newNimNode(typeNode.kind)
      for i in 0 ..< typeNode.len-1:
        ofBranch.add copyNimTree(typeNode[i])
      let dstInner = newNimNode(nnkStmtListExpr)
      foldObjectBody(dstInner, typeNode[^1], tmpSym, jsonNode, jsonPath, originalJsonPathLen)
      # resOuter now contains the inner stmtList
      ofBranch.add dstInner
      dst[^1].expectKind nnkCaseStmt
      dst[^1].add ofBranch

    of nnkObjectTy:
      typeNode[0].expectKind nnkEmpty
      typeNode[1].expectKind {nnkEmpty, nnkOfInherit}
      if typeNode[1].kind == nnkOfInherit:
        let base = typeNode[1][0]
        var impl = getTypeImpl(base)
        while impl.kind in {nnkRefTy, nnkPtrTy}:
          impl = getTypeImpl(impl[0])
        foldObjectBody(dst, impl, tmpSym, jsonNode, jsonPath, originalJsonPathLen)
      let body = typeNode[2]
      foldObjectBody(dst, body, tmpSym, jsonNode, jsonPath, originalJsonPathLen)

    else:
      error("unhandled kind: " & $typeNode.kind, typeNode)


  macro assignObjectImpl[T](dst: var T; jsonNode: JsonNode; jsonPath: var string) =
    let typeSym = getTypeInst(dst)
    let originalJsonPathLen = genSym(nskLet, "originalJsonPathLen")
    result = newStmtList()
    result.add quote do:
      let `originalJsonPathLen` = len(`jsonPath`)
    if typeSym.kind in {nnkTupleTy, nnkTupleConstr}:
      # both, `dst` and `typeSym` don't have good lineinfo. But nothing
      # else is available here.
      detectIncompatibleType(typeSym, dst)
      foldObjectBody(result, typeSym, dst, jsonNode, jsonPath, originalJsonPathLen)
    else:
      foldObjectBody(result, typeSym.getTypeImpl, dst, jsonNode, jsonPath, originalJsonPathLen)

  proc initFromJson[T : object|tuple](dst: var T; jsonNode: JsonNode; jsonPath: var string) =
    assignObjectImpl(dst, jsonNode, jsonPath)

  proc to*[T](node: JsonNode, t: typedesc[T]): T =
    ## `Unmarshals`:idx: the specified node into the object type specified.
    ##
    ## Known limitations:
    ##
    ##   * Heterogeneous arrays are not supported.
    ##   * Sets in object variants are not supported.
    ##   * Not nil annotations are not supported.
    ##
    ## Example:
    ##
    ## .. code-block:: Nim
    ##     let jsonNode = parseJson("""
    ##        {
    ##          "person": {
    ##            "name": "Nimmer",
    ##            "age": 21
    ##          },
    ##          "list": [1, 2, 3, 4]
    ##        }
    ##     """)
    ##
    ##     type
    ##       Person = object
    ##         name: string
    ##         age: int
    ##
    ##       Data = object
    ##         person: Person
    ##         list: seq[int]
    ##
    ##     var data = to(jsonNode, Data)
    ##     doAssert data.person.name == "Nimmer"
    ##     doAssert data.person.age == 21
    ##     doAssert data.list == @[1, 2, 3, 4]

    var jsonPath = ""
    initFromJson(result, node, jsonPath)

when false:
  import os
  var s = newFileStream(paramStr(1), fmRead)
  if s == nil: quit("cannot open the file" & paramStr(1))
  var x: JsonParser
  open(x, s, paramStr(1))
  while true:
    next(x)
    case x.kind
    of jsonError:
      Echo(x.errorMsg())
      break
    of jsonEof: break
    of jsonString, jsonInt, jsonFloat: echo(x.str)
    of jsonTrue: echo("!TRUE")
    of jsonFalse: echo("!FALSE")
    of jsonNull: echo("!NULL")
    of jsonObjectStart: echo("{")
    of jsonObjectEnd: echo("}")
    of jsonArrayStart: echo("[")
    of jsonArrayEnd: echo("]")

  close(x)

# { "json": 5 }
# To get that we shall use, obj["json"]

when isMainModule:
  # Note: Macro tests are in tests/stdlib/tjsonmacro.nim

  let testJson = parseJson"""{ "a": [1, 2, 3, 4], "b": "asd", "c": "\ud83c\udf83", "d": "\u00E6"}"""
  # nil passthrough
  doAssert(testJson{"doesnt_exist"}{"anything"}.isNil)
  testJson{["e", "f"]} = %true
  doAssert(testJson["e"]["f"].bval)

  # make sure UTF-16 decoding works.
  doAssert(testJson["c"].str == "🎃")
  doAssert(testJson["d"].str == "æ")

  # make sure no memory leek when parsing invalid string
  let startMemory = getOccupiedMem()
  for i in 0 .. 10000:
    try:
      discard parseJson"""{ invalid"""
    except:
      discard
  # memory diff should less than 4M
  doAssert(abs(getOccupiedMem() - startMemory) < 4 * 1024 * 1024)


  # test `$`
  let stringified = $testJson
  let parsedAgain = parseJson(stringified)
  doAssert(parsedAgain["b"].str == "asd")

  parsedAgain["abc"] = %5
  doAssert parsedAgain["abc"].num == 5

  # Bounds checking
  when compileOption("boundChecks"):
    try:
      let a = testJson["a"][9]
      doAssert(false, "IndexError not thrown")
    except IndexError:
      discard
    try:
      let a = testJson["a"][-1]
      doAssert(false, "IndexError not thrown")
    except IndexError:
      discard
    try:
      doAssert(testJson["a"][0].num == 1, "Index doesn't correspond to its value")
    except:
      doAssert(false, "IndexError thrown for valid index")

  doAssert(testJson{"b"}.getStr() == "asd", "Couldn't fetch a singly nested key with {}")
  doAssert(isNil(testJson{"nonexistent"}), "Non-existent keys should return nil")
  doAssert(isNil(testJson{"a", "b"}), "Indexing through a list should return nil")
  doAssert(isNil(testJson{"a", "b"}), "Indexing through a list should return nil")
  doAssert(testJson{"a"} == parseJson"[1, 2, 3, 4]", "Didn't return a non-JObject when there was one to be found")
  doAssert(isNil(parseJson("[1, 2, 3]"){"foo"}), "Indexing directly into a list should return nil")

  # Generator:
  var j = %* [{"name": "John", "age": 30}, {"name": "Susan", "age": 31}]
  doAssert j == %[%{"name": %"John", "age": %30}, %{"name": %"Susan", "age": %31}]

  var j2 = %*
    [
      {
        "name": "John",
        "age": 30
      },
      {
        "name": "Susan",
        "age": 31
      }
    ]
  doAssert j2 == %[%{"name": %"John", "age": %30}, %{"name": %"Susan", "age": %31}]

  var name = "John"
  let herAge = 30
  const hisAge = 31

  var j3 = %*
    [ {"name": "John"
      , "age": herAge
      }
    , {"name": "Susan"
      , "age": hisAge
      }
    ]
  doAssert j3 == %[%{"name": %"John", "age": %30}, %{"name": %"Susan", "age": %31}]

  var j4 = %*{"test": nil}
  doAssert j4 == %{"test": newJNull()}

  let seqOfNodes = @[%1, %2]
  let jSeqOfNodes = %seqOfNodes
  doAssert(jSeqOfNodes[1].num == 2)

  type MyObj = object
    a, b: int
    s: string
    f32: float32
    f64: float64
    next: ref MyObj
  var m: MyObj
  m.s = "hi"
  m.a = 5
  let jMyObj = %m
  doAssert(jMyObj["a"].num == 5)
  doAssert(jMyObj["s"].str == "hi")

  # Test loading of file.
  when not defined(js):
    var parsed = parseFile("tests/testdata/jsontest.json")

    try:
      discard parsed["key2"][12123]
      doAssert(false)
    except IndexError: doAssert(true)

    var parsed2 = parseFile("tests/testdata/jsontest2.json")
    doAssert(parsed2{"repository", "description"}.str ==
        "IRC Library for Haskell", "Couldn't fetch via multiply nested key using {}")

  doAssert escapeJsonUnquoted("\10Foo🎃barÄ") == "\\nFoo🎃barÄ"
  doAssert escapeJsonUnquoted("\0\7\20") == "\\u0000\\u0007\\u0014" # for #7887
  doAssert escapeJson("\10Foo🎃barÄ") == "\"\\nFoo🎃barÄ\""
  doAssert escapeJson("\0\7\20") == "\"\\u0000\\u0007\\u0014\"" # for #7887

  # Test with extra data
  when not defined(js):
    try:
      discard parseJson("123 456")
      doAssert(false)
    except JsonParsingError:
      doAssert getCurrentExceptionMsg().contains(errorMessages[errEofExpected])

    try:
      discard parseFile("tests/testdata/jsonwithextradata.json")
      doAssert(false)
    except JsonParsingError:
      doAssert getCurrentExceptionMsg().contains(errorMessages[errEofExpected])

  # bug #6438
  doAssert($ %*[] == "[]")
  doAssert($ %*{} == "{}")

  doAssert(not compiles(%{"error": "No messages"}))

  # bug #9111
  block:
    type
      Bar = string
      Foo = object
        a: int
        b: Bar

    let
      js = """{"a": 123, "b": "abc"}""".parseJson
      foo = js.to Foo

    doAssert(foo.b == "abc")

  # Generate constructors for range[T] types
  block:
    type
      Q1 = range[0'u8 .. 50'u8]
      Q2 = range[0'u16 .. 50'u16]
      Q3 = range[0'u32 .. 50'u32]
      Q4 = range[0'i8 .. 50'i8]
      Q5 = range[0'i16 .. 50'i16]
      Q6 = range[0'i32 .. 50'i32]
      Q7 = range[0'f32 .. 50'f32]
      Q8 = range[0'f64 .. 50'f64]
      Q9 = range[0 .. 50]

      X = object
        m1: Q1
        m2: Q2
        m3: Q3
        m4: Q4
        m5: Q5
        m6: Q6
        m7: Q7
        m8: Q8
        m9: Q9

    let obj = X(
      m1: Q1(42),
      m2: Q2(42),
      m3: Q3(42),
      m4: Q4(42),
      m5: Q5(42),
      m6: Q6(42),
      m7: Q7(42),
      m8: Q8(42),
      m9: Q9(42)
    )

    doAssert(obj == to(%obj, type(obj)))

    when not defined(js):
      const fragments = """[1,2,3] {"hi":3} 12 [] """
      var res = ""
      for x in parseJsonFragments(newStringStream(fragments)):
        res.add($x)
        res.add " "
      doAssert res == fragments


  # test isRefSkipDistinct
  type
    MyRef = ref object
    MyObject = object
    MyDistinct = distinct MyRef
    MyOtherDistinct = distinct MyRef

  var x0: ref int
  var x1: MyRef
  var x2: MyObject
  var x3: MyDistinct
  var x4: MyOtherDistinct

  doAssert isRefSkipDistinct(x0)
  doAssert isRefSkipDistinct(x1)
  doAssert not isRefSkipDistinct(x2)
  doAssert isRefSkipDistinct(x3)
  doAssert isRefSkipDistinct(x4)


  doAssert isRefSkipDistinct(ref int)
  doAssert isRefSkipDistinct(MyRef)
  doAssert not isRefSkipDistinct(MyObject)
  doAssert isRefSkipDistinct(MyDistinct)
  doAssert isRefSkipDistinct(MyOtherDistinct)