Handle template parameter key dependents more intelligently.

mwparserfromhell/nodes/template.py

@@ -143,10 +143,21 @@ class Template(Node):
 
         if showkey is None:
             try:
-                int(unicode(name))
-                showkey = False                                                     # DEPENDENTS?
+                int_name = int(unicode(name))
             except ValueError:
                 showkey = True
+            else:
+                int_keys = set()
+                for param in self.params:
+                    try:
+                        int_keys.add(int(unicode(param.name)))
+                    except ValueError:
+                        pass
+                expected = min(set(range(1, len(int_keys) + 2)) - int_keys)
+                if expected == int_name:
+                    showkey = False
+                else:
+                    showkey = True
         if not showkey:
             self._surface_escape(value, "=")
         if not force_nonconformity:

mwparserfromhell/parser/builder.py

@@ -20,8 +20,6 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-import re
-
 from . import tokens
 from ..nodes import Heading, HTMLEntity, Tag, Template, Text
 from ..nodes.extras import Attribute, Parameter
@@ -78,9 +76,11 @@ class Builder(object):
                     name = self._pop()
                 default = self._wrap(unicode(min(int_key_range - int_keys)))
                 param = self._handle_parameter(default)
-                if re.match(r"[1-9][0-9]*$", param.name.strip()):
+                try:
                     int_keys.add(int(unicode(param.name)))
                     int_key_range.add(len(int_keys) + 1)
+                except ValueError:
+                    pass
                 params.append(param)
             elif isinstance(token, tokens.TemplateClose):
                 if not params: