Merge pull request tornadoweb#495 from alekstorm/template_try_else

Add `else` as possible sub-clause in `try` blocks in templates.

tornado/template.py

@@ -165,7 +165,7 @@ def add(x, y):
 ``{% set *x* = *y* %}``
     Sets a local variable.
 
-``{% try %}...{% except %}...{% finally %}...{% end %}``
+``{% try %}...{% except %}...{% finally %}...{% else %}...{% end %}``
     Same as the python ``try`` statement.
 
 ``{% while *condition* %}... {% end %}``
@@ -757,7 +757,7 @@ def _parse(reader, template, in_block=None):
 
         # Intermediate ("else", "elif", etc) blocks
         intermediate_blocks = {
-            "else": set(["if", "for", "while"]),
+            "else": set(["if", "for", "while", "try"]),
             "elif": set(["if"]),
             "except": set(["try"]),
             "finally": set(["try"]),

tornado/test/template_test.py

@@ -101,6 +101,16 @@ def test_if(self):
         self.assertEqual(template.generate(x=5), b("yes"))
         self.assertEqual(template.generate(x=3), b("no"))
 
+    def test_try(self):
+        template = Template(utf8("""{% try %}
+try{% set y = 1/x %}
+{% except %}-except
+{% else %}-else
+{% finally %}-finally
+{% end %}"""))
+        self.assertEqual(template.generate(x=1), b("\ntry\n-else\n-finally\n"))
+        self.assertEqual(template.generate(x=0), b("\ntry-except\n-finally\n"))
+
     def test_comment_directive(self):
         template = Template(utf8("{% comment blah blah %}foo"))
         self.assertEqual(template.generate(), b("foo"))