1 files changed, 93 insertions, 0 deletions
diff --git a/src/jinja2/nativetypes.py b/src/jinja2/nativetypes.py
new file mode 100644
index 00000000..5ecf72b5
--- /dev/null
+++ b/src/jinja2/nativetypes.py
@@ -0,0 +1,93 @@
+from ast import literal_eval
+from itertools import chain
+from itertools import islice
+
+from . import nodes
+from .compiler import CodeGenerator
+from .compiler import has_safe_repr
+from .environment import Environment
+from .environment import Template
+
+
+def native_concat(nodes):
+    """Return a native Python type from the list of compiled nodes. If
+    the result is a single node, its value is returned. Otherwise, the
+    nodes are concatenated as strings. If the result can be parsed with
+    :func:`ast.literal_eval`, the parsed value is returned. Otherwise,
+    the string is returned.
+
+    :param nodes: Iterable of nodes to concatenate.
+    """
+    head = list(islice(nodes, 2))
+
+    if not head:
+        return None
+
+    if len(head) == 1:
+        raw = head[0]
+    else:
+        raw = "".join([str(v) for v in chain(head, nodes)])
+
+    try:
+        return literal_eval(raw)
+    except (ValueError, SyntaxError, MemoryError):
+        return raw
+
+
+class NativeCodeGenerator(CodeGenerator):
+    """A code generator which renders Python types by not adding
+    ``str()`` around output nodes.
+    """
+
+    @staticmethod
+    def _default_finalize(value):
+        return value
+
+    def _output_const_repr(self, group):
+        return repr("".join([str(v) for v in group]))
+
+    def _output_child_to_const(self, node, frame, finalize):
+        const = node.as_const(frame.eval_ctx)
+
+        if not has_safe_repr(const):
+            raise nodes.Impossible()
+
+        if isinstance(node, nodes.TemplateData):
+            return const
+
+        return finalize.const(const)
+
+    def _output_child_pre(self, node, frame, finalize):
+        if finalize.src is not None:
+            self.write(finalize.src)
+
+    def _output_child_post(self, node, frame, finalize):
+        if finalize.src is not None:
+            self.write(")")
+
+
+class NativeEnvironment(Environment):
+    """An environment that renders templates to native Python types."""
+
+    code_generator_class = NativeCodeGenerator
+
+
+class NativeTemplate(Template):
+    environment_class = NativeEnvironment
+
+    def render(self, *args, **kwargs):
+        """Render the template to produce a native Python type. If the
+        result is a single node, its value is returned. Otherwise, the
+        nodes are concatenated as strings. If the result can be parsed
+        with :func:`ast.literal_eval`, the parsed value is returned.
+        Otherwise, the string is returned.
+        """
+        vars = dict(*args, **kwargs)
+
+        try:
+            return native_concat(self.root_render_func(self.new_context(vars)))
+        except Exception:
+            return self.environment.handle_exception()
+
+
+NativeEnvironment.template_class = NativeTemplate