Merge 0698095 into 1c29dac

simpleeval.py

@@ -271,6 +271,11 @@ def __init__(self, operators=None, functions=None, names=None):
         elif isinstance(self.names, dict) and "None" not in self.names:
             self.names["None"] = None
 
+        # py3.6, f-strings
+        if hasattr(ast, 'JoinedStr'):
+            self.nodes[ast.JoinedStr] = self._eval_joinedstr  # f-string
+            self.nodes[ast.FormattedValue] = self._eval_formattedvalue  # formatted value in f-string
+
     def eval(self, expr):
         """ evaluate an expresssion, using the operators, functions and
             names previously set up. """
@@ -433,6 +438,19 @@ def _eval_slice(self, node):
             step = self._eval(node.step)
         return slice(lower, upper, step)
 
+    def _eval_joinedstr(self, node):
+        evaluated_values = [str(self._eval(n)) for n in node.values]
+        if sum(len(v) for v in evaluated_values) > MAX_STRING_LENGTH:
+            raise IterableTooLong("Sorry, I will not evaluate something this long.")
+        return ''.join(evaluated_values)
+
+    def _eval_formattedvalue(self, node):
+        if node.format_spec:
+            fmt = "{:" + self._eval(node.format_spec) + "}"
+            return fmt.format(self._eval(node.value))
+        else:
+            return self._eval(node.value)
+
 
 class EvalWithCompoundTypes(SimpleEval):
     """

test_simpleeval.py

@@ -6,7 +6,7 @@
 
 """
 # pylint: disable=too-many-public-methods, missing-docstring
-
+import sys
 import unittest
 import operator
 import ast
@@ -154,6 +154,14 @@ def test_is(self):
         self.t('1 is not None', True)
         self.t('None is not None', False)
 
+    def test_fstring(self):
+        if sys.version_info >= (3, 6, 0):
+            self.t('f""', "")
+            self.t('f"stuff"', "stuff")
+            self.t('f"one is {1} and two is {2}"', "one is 1 and two is 2")
+            self.t('f"1+1 is {1+1}"', "1+1 is 2")
+            self.t('f"{\'dramatic\':!<11}"', "dramatic!!!")
+
 
 class TestFunctions(DRYTest):
     """ Functions for expressions to play with """
@@ -328,6 +336,10 @@ def test_string_length(self):
         with self.assertRaises(simpleeval.IterableTooLong):
             self.t("'" + (50000 * "stuff") + "'", 0)
 
+        if sys.version_info >= (3, 6, 0):
+            with self.assertRaises(simpleeval.IterableTooLong):
+                self.t("f'{\"foo\"*50000}'", 0)
+
     def test_bytes_array_test(self):
         self.t("'20000000000000000000'.encode() * 5000",
                '20000000000000000000'.encode() * 5000)
@@ -405,6 +417,51 @@ def test_string_format(self):
         with self.assertRaises(simpleeval.FeatureNotAvailable):
              self.t('"{string.__class__}".format(string="things")', 0)
 
+        if sys.version_info >= (3, 6, 0):
+            self.s.names['x'] = 42
+
+            with self.assertRaises(simpleeval.FeatureNotAvailable):
+                self.t('f"{x.__class__}"', 0)
+
+            self.s.names['x'] = lambda y: y
+
+            with self.assertRaises(simpleeval.FeatureNotAvailable):
+                self.t('f"{x.__globals__}"', 0)
+
+            class EscapeArtist(object):
+                @staticmethod
+                def trapdoor():
+                    return 42
+
+                @staticmethod
+                def _quasi_private():
+                    return 84
+
+            self.s.names['houdini'] = EscapeArtist()  # let's just retest this, but in a f-string
+
+            with self.assertRaises(simpleeval.FeatureNotAvailable):
+                self.t('f"{houdini.trapdoor.__globals__}"', 0)
+
+            with self.assertRaises(simpleeval.FeatureNotAvailable):
+                self.t('f"{houdini.trapdoor.func_globals}"', 0)
+
+            with self.assertRaises(simpleeval.FeatureNotAvailable):
+                self.t('f"{houdini._quasi_private()}"', 0)
+
+            # and test for changing '_' to '__':
+
+            dis = simpleeval.DISALLOW_PREFIXES
+            simpleeval.DISALLOW_PREFIXES = ['func_']
+
+            self.t('f"{houdini.trapdoor()}"', "42")
+            self.t('f"{houdini._quasi_private()}"', "84")
+
+            # and return things to normal
+
+            simpleeval.DISALLOW_PREFIXES = dis
+
+
+
 class TestCompoundTypes(DRYTest):
     """ Test the compound-types edition of the library """