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import logging
import sys
import os.path
import ply.yacc
from jsonpath_ng.exceptions import JsonPathParserError
from jsonpath_ng.jsonpath import *
from jsonpath_ng.lexer import JsonPathLexer
logger = logging.getLogger(__name__)
def parse(string):
return JsonPathParser().parse(string)
class JsonPathParser:
'''
An LALR-parser for JsonPath
'''
tokens = JsonPathLexer.tokens
def __init__(self, debug=False, lexer_class=None):
if self.__doc__ is None:
raise JsonPathParserError(
'Docstrings have been removed! By design of PLY, '
'jsonpath-rw requires docstrings. You must not use '
'PYTHONOPTIMIZE=2 or python -OO.'
)
self.debug = debug
self.lexer_class = lexer_class or JsonPathLexer # Crufty but works around statefulness in PLY
# Since PLY has some crufty aspects and dumps files, we try to keep them local
# However, we need to derive the name of the output Python file :-/
output_directory = os.path.dirname(__file__)
try:
module_name = os.path.splitext(os.path.split(__file__)[1])[0]
except:
module_name = __name__
start_symbol = 'jsonpath'
parsing_table_module = '_'.join([module_name, start_symbol, 'parsetab'])
# Generate the parse table
self.parser = ply.yacc.yacc(module=self,
debug=self.debug,
tabmodule = parsing_table_module,
outputdir = output_directory,
write_tables=0,
start = start_symbol,
errorlog = logger)
def parse(self, string, lexer = None):
lexer = lexer or self.lexer_class()
return self.parse_token_stream(lexer.tokenize(string))
def parse_token_stream(self, token_iterator):
return self.parser.parse(lexer = IteratorToTokenStream(token_iterator))
# ===================== PLY Parser specification =====================
precedence = [
('left', ','),
('left', 'DOUBLEDOT'),
('left', '.'),
('left', '|'),
('left', '&'),
('left', 'WHERE'),
('left', 'WHERENOT'),
]
def p_error(self, t):
if t is None:
raise JsonPathParserError('Parse error near the end of string!')
raise JsonPathParserError('Parse error at %s:%s near token %s (%s)'
% (t.lineno, t.col, t.value, t.type))
def p_jsonpath_binop(self, p):
"""jsonpath : jsonpath '.' jsonpath
| jsonpath DOUBLEDOT jsonpath
| jsonpath WHERE jsonpath
| jsonpath WHERENOT jsonpath
| jsonpath '|' jsonpath
| jsonpath '&' jsonpath"""
op = p[2]
if op == '.':
p[0] = Child(p[1], p[3])
elif op == '..':
p[0] = Descendants(p[1], p[3])
elif op == 'where':
p[0] = Where(p[1], p[3])
elif op == 'wherenot':
p[0] = WhereNot(p[1], p[3])
elif op == '|':
p[0] = Union(p[1], p[3])
elif op == '&':
p[0] = Intersect(p[1], p[3])
def p_jsonpath_fields(self, p):
"jsonpath : fields_or_any"
p[0] = Fields(*p[1])
def p_jsonpath_named_operator(self, p):
"jsonpath : NAMED_OPERATOR"
if p[1] == 'this':
p[0] = This()
elif p[1] == 'parent':
p[0] = Parent()
else:
raise JsonPathParserError('Unknown named operator `%s` at %s:%s'
% (p[1], p.lineno(1), p.lexpos(1)))
def p_jsonpath_root(self, p):
"jsonpath : '$'"
p[0] = Root()
def p_jsonpath_idx(self, p):
"jsonpath : '[' idx ']'"
p[0] = p[2]
def p_jsonpath_slice(self, p):
"jsonpath : '[' slice ']'"
p[0] = p[2]
def p_jsonpath_fieldbrackets(self, p):
"jsonpath : '[' fields ']'"
p[0] = Fields(*p[2])
def p_jsonpath_child_fieldbrackets(self, p):
"jsonpath : jsonpath '[' fields ']'"
p[0] = Child(p[1], Fields(*p[3]))
def p_jsonpath_child_idxbrackets(self, p):
"jsonpath : jsonpath '[' idx ']'"
p[0] = Child(p[1], p[3])
def p_jsonpath_child_slicebrackets(self, p):
"jsonpath : jsonpath '[' slice ']'"
p[0] = Child(p[1], p[3])
def p_jsonpath_parens(self, p):
"jsonpath : '(' jsonpath ')'"
p[0] = p[2]
# Because fields in brackets cannot be '*' - that is reserved for array indices
def p_fields_or_any(self, p):
"""fields_or_any : fields
| '*'
| NUMBER"""
if p[1] == '*':
p[0] = ['*']
elif isinstance(p[1], int):
p[0] = str(p[1])
else:
p[0] = p[1]
def p_fields_id(self, p):
"fields : ID"
p[0] = [p[1]]
def p_fields_comma(self, p):
"fields : fields ',' fields"
p[0] = p[1] + p[3]
def p_idx(self, p):
"idx : NUMBER"
p[0] = Index(p[1])
def p_slice_any(self, p):
"slice : '*'"
p[0] = Slice()
def p_slice(self, p): # Currently does not support `step`
"""slice : maybe_int ':' maybe_int
| maybe_int ':' maybe_int ':' maybe_int """
p[0] = Slice(*p[1::2])
def p_maybe_int(self, p):
"""maybe_int : NUMBER
| empty"""
p[0] = p[1]
def p_empty(self, p):
'empty :'
p[0] = None
class IteratorToTokenStream:
def __init__(self, iterator):
self.iterator = iterator
def token(self):
try:
return next(self.iterator)
except StopIteration:
return None
if __name__ == '__main__':
logging.basicConfig()
parser = JsonPathParser(debug=True)
print(parser.parse(sys.stdin.read()))
|
