1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/compiler/future.py Tue May 01 22:04:53 2012 +0200
1.3 @@ -0,0 +1,73 @@
1.4 +"""Parser for future statements
1.5 +
1.6 +"""
1.7 +
1.8 +from compiler import ast, walk
1.9 +
1.10 +def is_future(stmt):
1.11 + """Return true if statement is a well-formed future statement"""
1.12 + if not isinstance(stmt, ast.From):
1.13 + return 0
1.14 + if stmt.modname == "__future__":
1.15 + return 1
1.16 + else:
1.17 + return 0
1.18 +
1.19 +class FutureParser:
1.20 +
1.21 + features = ("nested_scopes", "generators", "division",
1.22 + "absolute_import", "with_statement")
1.23 +
1.24 + def __init__(self):
1.25 + self.found = {} # set
1.26 +
1.27 + def visitModule(self, node):
1.28 + stmt = node.node
1.29 + for s in stmt.nodes:
1.30 + if not self.check_stmt(s):
1.31 + break
1.32 +
1.33 + def check_stmt(self, stmt):
1.34 + if is_future(stmt):
1.35 + for name, asname in stmt.names:
1.36 + if name in self.features:
1.37 + self.found[name] = 1
1.38 + else:
1.39 + raise SyntaxError, \
1.40 + "future feature %s is not defined" % name
1.41 + stmt.valid_future = 1
1.42 + return 1
1.43 + return 0
1.44 +
1.45 + def get_features(self):
1.46 + """Return list of features enabled by future statements"""
1.47 + return self.found.keys()
1.48 +
1.49 +class BadFutureParser:
1.50 + """Check for invalid future statements"""
1.51 +
1.52 + def visitFrom(self, node):
1.53 + if hasattr(node, 'valid_future'):
1.54 + return
1.55 + if node.modname != "__future__":
1.56 + return
1.57 + raise SyntaxError, "invalid future statement " + repr(node)
1.58 +
1.59 +def find_futures(node):
1.60 + p1 = FutureParser()
1.61 + p2 = BadFutureParser()
1.62 + walk(node, p1)
1.63 + walk(node, p2)
1.64 + return p1.get_features()
1.65 +
1.66 +if __name__ == "__main__":
1.67 + import sys
1.68 + from compiler import parseFile, walk
1.69 +
1.70 + for file in sys.argv[1:]:
1.71 + print file
1.72 + tree = parseFile(file)
1.73 + v = FutureParser()
1.74 + walk(tree, v)
1.75 + print v.found
1.76 + print