1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
# orm/evaluator.py
# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
import operator
from ..sql import operators
class UnevaluatableError(Exception):
pass
_straight_ops = set(getattr(operators, op)
for op in ('add', 'mul', 'sub',
'div',
'mod', 'truediv',
'lt', 'le', 'ne', 'gt', 'ge', 'eq'))
_notimplemented_ops = set(getattr(operators, op)
for op in ('like_op', 'notlike_op', 'ilike_op',
'notilike_op', 'between_op', 'in_op',
'notin_op', 'endswith_op', 'concat_op'))
class EvaluatorCompiler(object):
def process(self, clause):
meth = getattr(self, "visit_%s" % clause.__visit_name__, None)
if not meth:
raise UnevaluatableError(
"Cannot evaluate %s" % type(clause).__name__)
return meth(clause)
def visit_grouping(self, clause):
return self.process(clause.element)
def visit_null(self, clause):
return lambda obj: None
def visit_false(self, clause):
return lambda obj: False
def visit_true(self, clause):
return lambda obj: True
def visit_column(self, clause):
if 'parentmapper' in clause._annotations:
key = clause._annotations['parentmapper'].\
_columntoproperty[clause].key
else:
key = clause.key
get_corresponding_attr = operator.attrgetter(key)
return lambda obj: get_corresponding_attr(obj)
def visit_clauselist(self, clause):
evaluators = list(map(self.process, clause.clauses))
if clause.operator is operators.or_:
def evaluate(obj):
has_null = False
for sub_evaluate in evaluators:
value = sub_evaluate(obj)
if value:
return True
has_null = has_null or value is None
if has_null:
return None
return False
elif clause.operator is operators.and_:
def evaluate(obj):
for sub_evaluate in evaluators:
value = sub_evaluate(obj)
if not value:
if value is None:
return None
return False
return True
else:
raise UnevaluatableError(
"Cannot evaluate clauselist with operator %s" %
clause.operator)
return evaluate
def visit_binary(self, clause):
eval_left, eval_right = list(map(self.process,
[clause.left, clause.right]))
operator = clause.operator
if operator is operators.is_:
def evaluate(obj):
return eval_left(obj) == eval_right(obj)
elif operator is operators.isnot:
def evaluate(obj):
return eval_left(obj) != eval_right(obj)
elif operator in _straight_ops:
def evaluate(obj):
left_val = eval_left(obj)
right_val = eval_right(obj)
if left_val is None or right_val is None:
return None
return operator(eval_left(obj), eval_right(obj))
else:
raise UnevaluatableError(
"Cannot evaluate %s with operator %s" %
(type(clause).__name__, clause.operator))
return evaluate
def visit_unary(self, clause):
eval_inner = self.process(clause.element)
if clause.operator is operators.inv:
def evaluate(obj):
value = eval_inner(obj)
if value is None:
return None
return not value
return evaluate
raise UnevaluatableError(
"Cannot evaluate %s with operator %s" %
(type(clause).__name__, clause.operator))
def visit_bindparam(self, clause):
val = clause.value
return lambda obj: val
|
