# See the License for the specific language governing permissions and
# limitations under the License.
-# Static interface to get Nit objects from a Json string.
+# Static interface to read Nit objects from JSON strings
#
-# `String::json_to_nit_object` returns an equivalent Nit object from
-# the Json source. This object can then be type checked by the usual
-# languages features (`isa` and `as`).
+# `Text::parse_json` returns a simple Nit object from the JSON source.
+# This object can then be type checked as usual with `isa` and `as`.
module static
-import standard
-private import json_parser
-private import json_lexer
-
-# Something that can be translated to JSON.
-interface Jsonable
- # Encode `self` in JSON.
- fun to_json: String is abstract
-end
+import parser_base
+intrude import error
redef class Text
- super Jsonable
- # Encode `self` in JSON.
+ # Removes JSON-escaping if necessary in a JSON string
+ #
+ # assert "\\\"string\\uD83D\\uDE02\\\"".unescape_json == "\"string😂\""
+ fun unescape_json: Text do
+ if not json_need_escape then return self
+ return self.json_to_nit_string
+ end
+
+ # Does `self` need treatment from JSON to Nit ?
#
- # assert "\t\"http://example.com\"\r\n\0\\".to_json ==
- # "\"\\t\\\"http:\\/\\/example.com\\\"\\r\\n\\u0000\\\\\""
- redef fun to_json do
- var buffer = new FlatBuffer
- buffer.add '\"'
- for i in [0..self.length[ do
+ # i.e. is there at least one `\` character in it ?
+ #
+ # assert not "string".json_need_escape
+ # assert "\\\"string\\\"".json_need_escape
+ private fun json_need_escape: Bool do return has('\\')
+
+ # Escapes `self` from a JSON string to a Nit string
+ #
+ # assert "\\\"string\\\"".json_to_nit_string == "\"string\""
+ # assert "\\nEscape\\t\\n".json_to_nit_string == "\nEscape\t\n"
+ # assert "\\u0041zu\\uD800\\uDFD3".json_to_nit_string == "Azu𐏓"
+ private fun json_to_nit_string: String do
+ var res = new FlatBuffer.with_capacity(byte_length)
+ var i = 0
+ var ln = self.length
+ while i < ln do
var char = self[i]
if char == '\\' then
- buffer.append "\\\\"
- else if char == '\"' then
- buffer.append "\\\""
- else if char == '\/' then
- buffer.append "\\/"
- else if char < 16.ascii then
- if char == '\n' then
- buffer.append "\\n"
- else if char == '\r' then
- buffer.append "\\r"
- else if char == '\t' then
- buffer.append "\\t"
- else if char == 0x0C.ascii then
- buffer.append "\\f"
- else if char == 0x08.ascii then
- buffer.append "\\b"
- else
- buffer.append "\\u000{char.ascii.to_hex}"
+ i += 1
+ char = self[i]
+ if char == 'b' then
+ char = 0x08.code_point
+ else if char == 'f' then
+ char = 0x0C.code_point
+ else if char == 'n' then
+ char = '\n'
+ else if char == 'r' then
+ char = '\r'
+ else if char == 't' then
+ char = '\t'
+ else if char == 'u' then
+ var u16_esc = from_utf16_digit(i + 1)
+ char = u16_esc.code_point
+ if char.is_surrogate and i + 10 < ln then
+ if self[i + 5] == '\\' and self[i + 6] == 'u' then
+ u16_esc <<= 16
+ u16_esc += from_utf16_digit(i + 7)
+ char = u16_esc.to_u32.from_utf16_surr.code_point
+ i += 6
+ else
+ char = 0xFFFD.code_point
+ end
+ end
+ i += 4
end
- else if char < ' ' then
- buffer.append "\\u00{char.ascii.to_hex}"
- else
- buffer.add char
+ # `"`, `/` or `\` => Keep `char` as-is.
end
+ res.add char
+ i += 1
end
- buffer.add '\"'
- return buffer.write_to_string
- end
-
- fun json_to_nit_object: nullable Object
- do
- var lexer = new Lexer_json(to_s)
- var parser = new Parser_json
- var tokens = lexer.lex
- parser.tokens.add_all(tokens)
- var root_node = parser.parse
- if root_node isa NStart then
- return root_node.n_0.to_nit_object
- else if root_node isa NLexerError then
- var pos = root_node.position
- print "Json lexer error: {root_node.message} at {pos or else "<unknown>"} for {root_node}"
- return null
- else if root_node isa NParserError then
- var pos = root_node.position
- print "Json parsing error: {root_node.message} at {pos or else "<unknown>"} for {root_node}"
- return null
- else abort
+ return res.to_s
end
-end
-redef class Buffer
-
- # Append the JSON representation of `jsonable` to `self`.
+ # Parse `self` as JSON.
#
- # Append `"null"` for `null`.
- private fun append_json_of(jsonable: nullable Jsonable) do
- if jsonable isa Jsonable then
- append jsonable.to_json
- else
- append "null"
- end
- end
-end
-
-redef class Int
- super Jsonable
-
- # Encode `self` in JSON.
+ # If `self` is not a valid JSON document or contains an unsupported escape
+ # sequence, return a `JSONParseError`.
#
- # assert 0.to_json == "0"
- # assert (-42).to_json == "-42"
- redef fun to_json do return self.to_s
-end
-
-redef class Float
- super Jsonable
-
- # Encode `self` in JSON.
+ # Example with `JsonObject`:
#
- # Note: Because this method use `to_s`, it may lose precision.
+ # var obj = "\{\"foo\": \{\"bar\": true, \"goo\": [1, 2, 3]\}\}".parse_json
+ # assert obj isa JsonObject
+ # assert obj["foo"] isa JsonObject
+ # assert obj["foo"].as(JsonObject)["bar"] == true
#
- # ~~~
- # # Will not work as expected.
- # # assert (-0.0).to_json == "-0.0"
+ # Example with `JsonArray`:
#
- # assert (.5).to_json == "0.5"
- # assert (0.0).to_json == "0.0"
- # ~~~
- redef fun to_json do return self.to_s
-end
-
-redef class Bool
- super Jsonable
-
- # Encode `self` in JSON.
+ # var arr = "[1, 2, 3]".parse_json
+ # assert arr isa JsonArray
+ # assert arr.length == 3
+ # assert arr.first == 1
+ # assert arr.last == 3
+ #
+ # Example with `String`:
#
- # assert true.to_json == "true"
- # assert false.to_json == "false"
- redef fun to_json do return self.to_s
+ # var str = "\"foo, bar, baz\"".parse_json
+ # assert str isa String
+ # assert str == "foo, bar, baz"
+ #
+ # Example of a syntax error:
+ #
+ # var error = "\{foo: \"bar\"\}".parse_json
+ # assert error isa JsonParseError
+ # assert error.to_s == "Bad key format Error: bad JSON entity"
+ fun parse_json: nullable Serializable do return (new JSONStringParser(self.to_s)).parse_entity
end
-# A map that can be translated into a JSON object.
-interface JsonMapRead[K: String, V: nullable Jsonable]
- super MapRead[K, V]
- super Jsonable
-
- # Encode `self` in JSON.
- #
- # var obj = new JsonObject
- # obj["foo"] = "bar"
- # assert obj.to_json == "\{\"foo\":\"bar\"\}"
- # obj = new JsonObject
- # obj["baz"] = null
- # assert obj.to_json == "\{\"baz\":null\}"
- redef fun to_json do
- var buffer = new FlatBuffer
- buffer.append "\{"
- var it = iterator
- if it.is_ok then
- append_json_entry(it, buffer)
- while it.is_ok do
- buffer.append ","
- append_json_entry(it, buffer)
- end
+redef class FlatText
+ redef fun json_need_escape do
+ var its = items
+ for i in [first_byte .. last_byte] do
+ if its[i] == 0x5C then return true
end
- it.finish
- buffer.append "\}"
- return buffer.write_to_string
+ return false
end
+end
- private fun append_json_entry(iterator: MapIterator[String, nullable Jsonable],
- buffer: Buffer) do
- buffer.append iterator.key.to_json
- buffer.append ":"
- buffer.append_json_of(iterator.item)
- iterator.next
+redef class Char
+ # Is `self` a valid number start ?
+ private fun is_json_num_start: Bool do
+ if self == '-' then return true
+ if self.is_numeric then return true
+ return false
end
-end
-# A JSON Object.
-class JsonObject
- super JsonMapRead[String, nullable Jsonable]
- super HashMap[String, nullable Jsonable]
+ # Is `self` a valid JSON separator ?
+ private fun is_json_separator: Bool do
+ if self == ':' then return true
+ if self == ',' then return true
+ if self == '{' then return true
+ if self == '}' then return true
+ if self == '[' then return true
+ if self == ']' then return true
+ if self == '"' then return true
+ if self.is_whitespace then return true
+ return false
+ end
end
-# A sequence that can be translated into a JSON array.
-class JsonSequenceRead[E: nullable Jsonable]
- super Jsonable
- super SequenceRead[E]
+# A simple ad-hoc JSON parser
+#
+# To parse a simple JSON document, read it as a String and give it to `parse_entity`
+# NOTE: if your document contains several non-nested entities, use `parse_entity` for each
+# JSON entity to parse
+class JSONStringParser
+ super StringProcessor
- # Encode `self` in JSON.
+ # Parses a JSON Entity
#
- # var arr = new JsonArray.with_items("foo", null)
- # assert arr.to_json == "[\"foo\",null]"
- # arr.pop
- # assert arr.to_json =="[\"foo\"]"
- # arr.pop
- # assert arr.to_json =="[]"
- redef fun to_json do
- var buffer = new FlatBuffer
- buffer.append "["
- var it = iterator
- if it.is_ok then
- append_json_entry(it, buffer)
- while it.is_ok do
- buffer.append ","
- append_json_entry(it, buffer)
+ # ~~~nit
+ # var p = new JSONStringParser("""{"numbers": [1,23,3], "string": "string"}""")
+ # assert p.parse_entity isa JsonObject
+ # ~~~
+ fun parse_entity: nullable Serializable do
+ var srclen = len
+ ignore_whitespaces
+ if pos >= srclen then return make_parse_error("Empty JSON")
+ var c = src[pos]
+ if c == '[' then
+ pos += 1
+ return parse_json_array
+ else if c == '"' then
+ var s = parse_json_string
+ return s
+ else if c == '{' then
+ pos += 1
+ return parse_json_object
+ else if c == 'f' then
+ if pos + 4 >= srclen then make_parse_error("Error: bad JSON entity")
+ if src[pos + 1] == 'a' and src[pos + 2] == 'l' and src[pos + 3] == 's' and src[pos + 4] == 'e' then
+ pos += 5
+ return false
end
+ return make_parse_error("Error: bad JSON entity")
+ else if c == 't' then
+ if pos + 3 >= srclen then make_parse_error("Error: bad JSON entity")
+ if src[pos + 1] == 'r' and src[pos + 2] == 'u' and src[pos + 3] == 'e' then
+ pos += 4
+ return true
+ end
+ return make_parse_error("Error: bad JSON entity")
+ else if c == 'n' then
+ if pos + 3 >= srclen then make_parse_error("Error: bad JSON entity")
+ if src[pos + 1] == 'u' and src[pos + 2] == 'l' and src[pos + 3] == 'l' then
+ pos += 4
+ return null
+ end
+ return make_parse_error("Error: bad JSON entity")
end
- it.finish
- buffer.append "]"
- return buffer.write_to_string
+ if not c.is_json_num_start then return make_parse_error("Bad JSON character")
+ return parse_json_number
end
- private fun append_json_entry(iterator: Iterator[nullable Jsonable],
- buffer: Buffer) do
- buffer.append_json_of(iterator.item)
- iterator.next
+ # Parses a JSON Array
+ fun parse_json_array: Serializable do
+ var max = len
+ if pos >= max then return make_parse_error("Incomplete JSON array")
+ var arr = new JsonArray
+ var c = src[pos]
+ while not c == ']' do
+ ignore_whitespaces
+ if pos >= max then return make_parse_error("Incomplete JSON array")
+ if src[pos] == ']' then break
+ var ent = parse_entity
+ #print "Parsed an entity {ent} for a JSON array"
+ if ent isa JsonParseError then return ent
+ arr.add ent
+ ignore_whitespaces
+ if pos >= max then return make_parse_error("Incomplete JSON array")
+ c = src[pos]
+ if c == ']' then break
+ if c != ',' then return make_parse_error("Bad array separator {c}")
+ pos += 1
+ end
+ pos += 1
+ return arr
end
-end
-
-# A JSON array.
-class JsonArray
- super JsonSequenceRead[nullable Jsonable]
- super Array[nullable Jsonable]
-end
-
-################################################################################
-# Redef parser
-redef class Nvalue
- fun to_nit_object: nullable Object is abstract
-end
-
-redef class Nvalue_number
- redef fun to_nit_object
- do
- var text = n_number.text
- if text.chars.has('.') or text.chars.has('e') or text.chars.has('E') then return text.to_f
- return text.to_i
+ # Parses a JSON Object
+ fun parse_json_object: Serializable do
+ var max = len
+ if pos >= max then return make_parse_error("Incomplete JSON object")
+ var obj = new JsonObject
+ var c = src[pos]
+ while not c == '}' do
+ ignore_whitespaces
+ if pos >= max then return make_parse_error("Malformed JSON object")
+ if src[pos] == '}' then break
+ var key = parse_entity
+ #print "Parsed key {key} for JSON object"
+ if not key isa String then return make_parse_error("Bad key format {key or else "null"}")
+ ignore_whitespaces
+ if pos >= max then return make_parse_error("Incomplete JSON object")
+ if not src[pos] == ':' then return make_parse_error("Bad key/value separator {src[pos]}")
+ pos += 1
+ ignore_whitespaces
+ var value = parse_entity
+ #print "Parsed value {value} for JSON object"
+ if value isa JsonParseError then return value
+ obj[key] = value
+ ignore_whitespaces
+ if pos >= max then return make_parse_error("Incomplete JSON object")
+ c = src[pos]
+ if c == '}' then break
+ if c != ',' then return make_parse_error("Bad object separator {src[pos]}")
+ pos += 1
+ end
+ pos += 1
+ return obj
end
-end
-
-redef class Nvalue_string
- redef fun to_nit_object do return n_string.to_nit_string
-end
-redef class Nvalue_true
- redef fun to_nit_object do return true
-end
-
-redef class Nvalue_false
- redef fun to_nit_object do return false
-end
+ # Creates a `JsonParseError` with the right message and location
+ protected fun make_parse_error(message: String): JsonParseError do
+ var err = new JsonParseError(message)
+ err.location = hot_location
+ return err
+ end
-redef class Nvalue_null
- redef fun to_nit_object do return null
-end
+ # Parses an Int or Float
+ fun parse_json_number: Serializable do
+ var max = len
+ var p = pos
+ var c = src[p]
+ var is_neg = false
+ if c == '-' then
+ is_neg = true
+ p += 1
+ if p >= max then return make_parse_error("Bad JSON number")
+ c = src[p]
+ end
+ var val = 0
+ while c.is_numeric do
+ val *= 10
+ val += c.to_i
+ p += 1
+ if p >= max then break
+ c = src[p]
+ end
+ if c == '.' then
+ p += 1
+ if p >= max then return make_parse_error("Bad JSON number")
+ c = src[p]
+ var fl = val.to_f
+ var frac = 0.1
+ while c.is_numeric do
+ fl += c.to_i.to_f * frac
+ frac /= 10.0
+ p += 1
+ if p >= max then break
+ c = src[p]
+ end
+ if c == 'e' or c == 'E' then
+ p += 1
+ var exp = 0
+ if p >= max then return make_parse_error("Malformed JSON number")
+ c = src[p]
+ while c.is_numeric do
+ exp *= 10
+ exp += c.to_i
+ p += 1
+ if p >= max then break
+ c = src[p]
+ end
+ fl *= (10 ** exp).to_f
+ end
+ if p < max and not c.is_json_separator then return make_parse_error("Malformed JSON number")
+ pos = p
+ if is_neg then return -fl
+ return fl
+ end
+ if c == 'e' or c == 'E' then
+ p += 1
+ if p >= max then return make_parse_error("Bad JSON number")
+ var exp = src[p].to_i
+ c = src[p]
+ while c.is_numeric do
+ exp *= 10
+ exp += c.to_i
+ p += 1
+ if p >= max then break
+ c = src[p]
+ end
+ val *= (10 ** exp)
+ end
+ if p < max and not src[p].is_json_separator then return make_parse_error("Malformed JSON number")
+ pos = p
+ if is_neg then return -val
+ return val
+ end
-redef class Nstring
- fun to_nit_string: String do
- var res = new FlatBuffer
- var i = 1
- while i < text.length - 1 do
- var char = text[i]
- if char == '\\' then
- i += 1
- char = text[i]
- if char == 'b' then
- char = 0x08.ascii
- else if char == 'f' then
- char = 0x0C.ascii
- else if char == 'n' then
- char = '\n'
- else if char == 'r' then
- char = '\r'
- else if char == 't' then
- char = '\t'
- else if char == 'u' then
- var code = text.substring(i + 1, 4).to_hex
- # TODO UTF-16 escaping is not supported yet.
- if code >= 128 then
- char = '?'
+ private var parse_str_buf = new FlatBuffer
+
+ # Parses and returns a Nit string from a JSON String
+ fun parse_json_string: Serializable do
+ var src = src
+ var ln = src.length
+ var p = pos
+ p += 1
+ if p > ln then return make_parse_error("Malformed JSON String")
+ var c = src[p]
+ var ret = parse_str_buf
+ var chunk_st = p
+ while c != '"' do
+ if c != '\\' then
+ p += 1
+ if p >= ln then return make_parse_error("Malformed JSON string")
+ c = src[p]
+ continue
+ end
+ ret.append_substring_impl(src, chunk_st, p - chunk_st)
+ p += 1
+ if p >= ln then return make_parse_error("Malformed Escape sequence in JSON string")
+ c = src[p]
+ if c == 'r' then
+ ret.add '\r'
+ p += 1
+ else if c == 'n' then
+ ret.add '\n'
+ p += 1
+ else if c == 't' then
+ ret.add '\t'
+ p += 1
+ else if c == 'u' then
+ var cp = 0
+ p += 1
+ for i in [0 .. 4[ do
+ cp <<= 4
+ if p >= ln then make_parse_error("Malformed \uXXXX Escape sequence in JSON string")
+ c = src[p]
+ if c >= '0' and c <= '9' then
+ cp += c.code_point - '0'.code_point
+ else if c >= 'a' and c <= 'f' then
+ cp += c.code_point - 'a'.code_point + 10
+ else if c >= 'A' and c <= 'F' then
+ cp += c.code_point - 'A'.code_point + 10
else
- char = code.ascii
+ make_parse_error("Malformed \uXXXX Escape sequence in JSON string")
end
- i += 4
+ p += 1
end
- # `"`, `/` or `\` => Keep `char` as-is.
+ c = cp.code_point
+ if cp >= 0xD800 and cp <= 0xDBFF then
+ if p >= ln then make_parse_error("Malformed \uXXXX Escape sequence in JSON string")
+ c = src[p]
+ if c != '\\' then make_parse_error("Malformed \uXXXX Escape sequence in JSON string")
+ p += 1
+ c = src[p]
+ if c != 'u' then make_parse_error("Malformed \uXXXX Escape sequence in JSON string")
+ var locp = 0
+ p += 1
+ for i in [0 .. 4[ do
+ locp <<= 4
+ if p > ln then make_parse_error("Malformed \uXXXX Escape sequence in JSON string")
+ c = src[p]
+ if c >= '0' and c <= '9' then
+ locp += c.code_point - '0'.code_point
+ else if c >= 'a' and c <= 'f' then
+ locp += c.code_point - 'a'.code_point + 10
+ else if c >= 'A' and c <= 'F' then
+ locp += c.code_point - 'A'.code_point + 10
+ else
+ make_parse_error("Malformed \uXXXX Escape sequence in JSON string")
+ end
+ p += 1
+ end
+ c = (((locp & 0x3FF) | ((cp & 0x3FF) << 10)) + 0x10000).code_point
+ end
+ ret.add c
+ else if c == 'b' then
+ ret.add 8.code_point
+ p += 1
+ else if c == 'f' then
+ ret.add '\f'
+ p += 1
+ else
+ p += 1
+ ret.add c
end
- res.add char
- i += 1
+ chunk_st = p
+ c = src[p]
end
- return res.write_to_string
+ pos = p + 1
+ if ret.is_empty then return src.substring(chunk_st, p - chunk_st)
+ ret.append_substring_impl(src, chunk_st, p - chunk_st)
+ var rets = ret.to_s
+ ret.clear
+ return rets
end
-end
-redef class Nvalue_object
- redef fun to_nit_object
- do
- var obj = new HashMap[String, nullable Object]
- var members = n_members
- if members != null then
- var pairs = members.pairs
- for pair in pairs do obj[pair.name] = pair.value
+ # Ignores any character until a JSON separator is encountered
+ fun ignore_until_separator do
+ var max = len
+ while pos < max do
+ if not src[pos].is_json_separator then return
end
- return obj
- end
-end
-
-redef class Nmembers
- fun pairs: Array[Npair] is abstract
-end
-
-redef class Nmembers_tail
- redef fun pairs
- do
- var arr = n_members.pairs
- arr.add n_pair
- return arr
end
end
-redef class Nmembers_head
- redef fun pairs do return [n_pair]
-end
-
-redef class Npair
- fun name: String do return n_string.to_nit_string
- fun value: nullable Object do return n_value.to_nit_object
-end
-
-redef class Nvalue_array
- redef fun to_nit_object
- do
- var arr = new Array[nullable Object]
- var elements = n_elements
- if elements != null then
- var items = elements.items
- for item in items do arr.add(item.to_nit_object)
- end
- return arr
- end
+# A map that can be translated into a JSON object.
+interface JsonMapRead[K: String, V: nullable Serializable]
+ super MapRead[K, V]
+ super Serializable
end
-redef class Nelements
- fun items: Array[Nvalue] is abstract
+# A JSON Object.
+class JsonObject
+ super JsonMapRead[String, nullable Serializable]
+ super HashMap[String, nullable Serializable]
end
-redef class Nelements_tail
- redef fun items
- do
- var items = n_elements.items
- items.add(n_value)
- return items
- end
+# A sequence that can be translated into a JSON array.
+class JsonSequenceRead[E: nullable Serializable]
+ super Serializable
+ super SequenceRead[E]
end
-redef class Nelements_head
- redef fun items do return [n_value]
+# A JSON array.
+class JsonArray
+ super JsonSequenceRead[nullable Serializable]
+ super Array[nullable Serializable]
end
nitlanguage / nit.git / blobdiff