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# -*- coding: utf-8 -*-
# Copyright © 2009/2023 Andrey Vlasovskikh
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to the following
# conditions:
#
# The above copyright notice and this permission notice shall be included in all copies
# or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
# OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""A JSON parser using funcparserlib.
The parser is based on [the JSON grammar][1].
[1]: https://tools.ietf.org/html/rfc4627
"""
import re
import sys
from pprint import pformat
from re import VERBOSE
from typing import (
List,
Sequence,
Optional,
Tuple,
Any,
Dict,
Match,
TypeVar,
Callable,
Text,
Union,
)
from funcparserlib.lexer import TokenSpec, make_tokenizer, Token, LexerError
from funcparserlib.parser import (
maybe,
many,
finished,
forward_decl,
NoParseError,
Parser,
tok,
)
ENCODING = "UTF-8"
# noinspection SpellCheckingInspection
regexps = {
"escaped": r"""
\\ # Escape
((?P<standard>["\\/bfnrt]) # Standard escapes
| (u(?P<unicode>[0-9A-Fa-f]{4}))) # uXXXX
""",
"unescaped": r"""
[^"\\] # Unescaped: avoid ["\\]
""",
}
re_esc = re.compile(regexps["escaped"], VERBOSE)
T = TypeVar("T")
JsonValue = Union[None, bool, dict, list, int, float, str]
JsonMember = Tuple[str, JsonValue]
def tokenize(s: str) -> List[Token]:
specs = [
TokenSpec("space", r"[ \t\r\n]+"),
TokenSpec("string", r'"(%(unescaped)s | %(escaped)s)*"' % regexps, VERBOSE),
TokenSpec(
"number",
r"""
-? # Minus
(0|([1-9][0-9]*)) # Int
(\.[0-9]+)? # Frac
([Ee][+-]?[0-9]+)? # Exp
""",
VERBOSE,
),
TokenSpec("op", r"[{}\[\]\-,:]"),
TokenSpec("name", r"[A-Za-z_][A-Za-z_0-9]*"),
]
useless = ["space"]
t = make_tokenizer(specs)
return [x for x in t(s) if x.type not in useless]
def parse(tokens: Sequence[Token]) -> JsonValue:
def const(x: T) -> Callable[[Any], T]:
return lambda _: x
def op(s: str) -> Parser[Token, str]:
return tok("op", s)
def n(s: str) -> Parser[Token, Text]:
return tok("name", s)
def make_array(
values: Optional[Tuple[JsonValue, List[JsonValue]]]
) -> List[JsonValue]:
if values is None:
return []
else:
return [values[0]] + values[1]
def make_object(
values: Optional[Tuple[JsonMember, List[JsonMember]]]
) -> Dict[str, Any]:
if values is None:
return {}
else:
first, rest = values
k, v = first
d = {k: v}
d.update(rest)
return d
def make_number(s: str) -> Union[int, float]:
try:
return int(s)
except ValueError:
return float(s)
def unescape(s: str) -> str:
std = {
'"': '"',
"\\": "\\",
"/": "/",
"b": "\b",
"f": "\f",
"n": "\n",
"r": "\r",
"t": "\t",
}
def sub(m: Match[str]) -> str:
if m.group("standard") is not None:
return std[m.group("standard")]
else:
return chr(int(m.group("unicode"), 16))
return re_esc.sub(sub, s)
def make_string(s: str) -> str:
return unescape(s[1:-1])
def make_member(values: JsonMember) -> JsonMember:
k, v = values
return k, v
null = n("null") >> const(None)
true = n("true") >> const(True)
false = n("false") >> const(False)
number = tok("number") >> make_number
string = tok("string") >> make_string
value: Parser[Token, JsonValue] = forward_decl().named("json_value")
member = string + -op(":") + value >> make_member
json_object = (
(-op("{") + maybe(member + many(-op(",") + member)) + -op("}")) >> make_object
).named("json_object")
json_array = (
(-op("[") + maybe(value + many(-op(",") + value)) + -op("]")) >> make_array
).named("json_array")
value.define(null | true | false | json_object | json_array | number | string)
json_text = value + -finished
return json_text.parse(tokens)
def loads(s: str) -> JsonValue:
return parse(tokenize(s))
def main() -> None:
try:
text = sys.stdin.read()
tree = loads(text)
print(pformat(tree))
except (NoParseError, LexerError) as e:
print("syntax error: %s" % e, file=sys.stderr)
sys.exit(1)
if __name__ == "__main__":
main()
|
