1 # Copyright 2006 Google, Inc. All Rights Reserved.
2 # Licensed to PSF under a Contributor Agreement.
3 
4 """Fixer for exec.
5 
6 This converts usages of the exec statement into calls to a built-in
7 exec() function.
8 
9 exec code in ns1, ns2 -> exec(code, ns1, ns2)
10 """
11 
12 # Local imports
13 from .. import pytree
14 from .. import fixer_base
15 from ..fixer_util import Comma, Name, Call
16 
17 
18 class FixExec(fixer_base.BaseFix):
19     BM_compatible = True
20 
21     PATTERN = """
22     exec_stmt< 'exec' a=any 'in' b=any [',' c=any] >
23     |
24     exec_stmt< 'exec' (not atom<'(' [any] ')'>) a=any >
25     """
26 
27     def transform(self, node, results):
28         assert results
29         syms = self.syms
30         a = results["a"]
31         b = results.get("b")
32         c = results.get("c")
33         args = [a.clone()]
34         args[0].prefix = ""
35         if b is not None:
36             args.extend([Comma(), b.clone()])
37         if c is not None:
38             args.extend([Comma(), c.clone()])
39 
40         return Call(Name(u"exec"), args, prefix=node.prefix)
41