From 5c4c7f9b61b5e7a17b5f094e8206c9e2e95448ec Mon Sep 17 00:00:00 2001
From: Michael Howitz <mh@gocept.com>
Date: Thu, 25 Jan 2018 12:26:43 +0100
Subject: [PATCH] Allow list comprehensions in
 ``RestrictionCapableEval.eval()``.

Fixes #95.
---
 docs/CHANGES.rst             | 5 ++++-
 src/RestrictedPython/Eval.py | 8 +++++++-
 tests/test_eval.py           | 7 +++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/docs/CHANGES.rst b/docs/CHANGES.rst
index 91bc291..9af2e61 100644
--- a/docs/CHANGES.rst
+++ b/docs/CHANGES.rst
@@ -7,6 +7,9 @@ Changes
 - Warn when using another Python implementation than CPython as it is not safe to use RestrictedPython with other versions than CPyton.
   See https://bitbucket.org/pypy/pypy/issues/2653 for PyPy.
 
+- Allow to use list comprehensions in the default implementation of
+  ``RestrictionCapableEval.eval()``.
+
 4.0b2 (2017-09-15)
 ------------------
 
@@ -62,7 +65,7 @@ Changes
 
 - Mostly complete rewrite based on Python AST module.
   [loechel (Alexander Loechel), icemac (Michael Howitz), stephan-hof (Stephan Hofmockel), tlotze (Thomas Lotze)]
-  
+
 - Support Python versions 3.4 up to 3.6.
 
 - switch to pytest
diff --git a/src/RestrictedPython/Eval.py b/src/RestrictedPython/Eval.py
index 836ea5e..221cd2d 100644
--- a/src/RestrictedPython/Eval.py
+++ b/src/RestrictedPython/Eval.py
@@ -35,6 +35,11 @@ def default_guarded_getitem(ob, index):
     return ob[index]
 
 
+def default_guarded_getiter(ob):
+    # No restrictions.
+    return ob
+
+
 class RestrictionCapableEval(object):
     """A base class for restricted code."""
 
@@ -99,7 +104,8 @@ def eval(self, mapping):
 
         global_scope = {
             '_getattr_': default_guarded_getattr,
-            '_getitem_': default_guarded_getitem
+            '_getitem_': default_guarded_getitem,
+            '_getiter_': default_guarded_getiter,
         }
 
         global_scope.update(self.globals)
diff --git a/tests/test_eval.py b/tests/test_eval.py
index 0499a04..d1acf10 100644
--- a/tests/test_eval.py
+++ b/tests/test_eval.py
@@ -95,3 +95,10 @@ def test_Eval__RestictionCapableEval__eval_1():
     ob.globals['c'] = 8
     result = ob.eval(dict(a=1, b=2, c=4))
     assert result == 11
+
+
+def test_Eval__RestictionCapableEval__eval__2():
+    """It allows to use list comprehensions."""
+    ob = RestrictionCapableEval("[item for item in (1, 2)]")
+    result = ob.eval({})
+    assert result == [1, 2]