73 lines
1.8 KiB
Python
73 lines
1.8 KiB
Python
"""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", "generators", "division",
|
|
"absolute_import", "with_statement")
|
|
|
|
def __init__(self):
|
|
self.found = {} # set
|
|
|
|
def visitModule(self, node):
|
|
stmt = node.node
|
|
for s in stmt.nodes:
|
|
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 " + repr(node)
|
|
|
|
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
|