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
|
"""Parser for future statements
"""
from compiler import ast, walk
def is_future(stmt):
"""Return true if statement is a well-formed future statement"""
if not isinstance(stmt, ast.From):
return 0
if stmt.modname == "__future__":
return 1
else:
return 0
class FutureParser:
features = ("nested_scopes",)
def __init__(self):
self.found = {} # set
def visitModule(self, node):
if node.doc is None:
off = 0
else:
off = 1
stmt = node.node
for s in stmt.nodes[off:]:
if not self.check_stmt(s):
break
def check_stmt(self, stmt):
if is_future(stmt):
for name, asname in stmt.names:
if name in self.features:
self.found[name] = 1
else:
raise SyntaxError, \
"future feature %s is not defined" % name
stmt.valid_future = 1
return 1
return 0
def get_features(self):
"""Return list of features enabled by future statements"""
return self.found.keys()
class BadFutureParser:
"""Check for invalid future statements"""
def visitFrom(self, node):
if hasattr(node, 'valid_future'):
return
if node.modname != "__future__":
return
raise SyntaxError, "invalid future statement"
def find_futures(node):
p1 = FutureParser()
p2 = BadFutureParser()
walk(node, p1)
walk(node, p2)
return p1.get_features()
if __name__ == "__main__":
import sys
from compiler import parseFile, walk
for file in sys.argv[1:]:
print file
tree = parseFile(file)
v = FutureParser()
walk(tree, v)
print v.found
print
|
