Simplify maxOccurs handling.

Fixes #15.

.travis.yml

@@ -6,7 +6,7 @@ python:
     - 3.4
     - 3.5
     - 3.6
-    - pypy-5.4.1
+    - pypy-5.6.0
     - pypy3.3-5.2-alpha1
 install:
     - pip install -U pip setuptools

CHANGES.rst

@@ -24,6 +24,9 @@ Change History for ZConfig
   documenting ZConfig components using their description and examples
   in Sphinx documentation.
 
+- Simplify internal schema processing of max and min occurrence
+  values. See https://github.com/zopefoundation/ZConfig/issues/15.
+
 3.1.0 (2015-10-17)
 ------------------
 

ZConfig/info.py

@@ -64,13 +64,15 @@ class BaseInfo(object):
 
     def __init__(self, name, datatype, minOccurs, maxOccurs, handler,
                  attribute):
-        if maxOccurs is not None:
-            if maxOccurs < 1:
-                raise ZConfig.SchemaError(
-                    "maxOccurs must be at least 1")
-            if minOccurs is not None and minOccurs > maxOccurs:
-                raise ZConfig.SchemaError(
-                    "minOccurs cannot be more than maxOccurs")
+        assert maxOccurs is not None, "Use Unbounded for an upper bound, not None"
+        assert minOccurs is not None, "Use 0 for a lower bound, not None"
+
+        if maxOccurs < 1:
+            raise ZConfig.SchemaError(
+                "maxOccurs must be at least 1")
+        if minOccurs > maxOccurs:
+            raise ZConfig.SchemaError(
+                "minOccurs cannot be more than maxOccurs")
         self.name = name
         self.datatype = datatype
         self.minOccurs = minOccurs
@@ -98,7 +100,6 @@ class BaseKeyInfo(AbstractBaseClass, BaseInfo):
 
     def __init__(self, name, datatype, minOccurs, maxOccurs, handler,
                  attribute):
-        assert minOccurs is not None
         BaseInfo.__init__(self, name, datatype, minOccurs, maxOccurs,
                           handler, attribute)
         self._finished = False
@@ -221,8 +222,6 @@ def __init__(self, name, sectiontype, minOccurs, maxOccurs, handler,
         # handler     - handler name called when value(s) must take effect,
         #               or None
         # attribute   - name of the attribute on the SectionValue object
-        assert maxOccurs is not None
-        # because we compare it to 1 which is a Py3 error
         if maxOccurs > 1:
             if name not in ('*', '+'):
                 raise ZConfig.SchemaError(

ZConfig/schema.py

@@ -367,7 +367,7 @@ def end_sectiontype(self):
     def start_section(self, attrs):
         sectiontype = self.get_sectiontype(attrs)
         handler = self.get_handler(attrs)
-        min = self.get_required(attrs) and 1 or 0
+        min = 1 if self.get_required(attrs) else 0
         any, name, attribute = self.get_name_info(attrs, "section", "*")
         if any and not attribute: # pragma: no cover
             # It seems like this is handled by get_name_info.
@@ -410,7 +410,7 @@ def end_abstracttype(self):
 
     def start_key(self, attrs):
         name, datatype, handler, attribute = self.get_key_info(attrs, "key")
-        min = self.get_required(attrs) and 1 or 0
+        min = 1 if self.get_required(attrs) else 0
         key = info.KeyInfo(name, datatype, min, handler, attribute)
         if "default" in attrs:
             if min:

ZConfig/tests/test_info.py

@@ -38,7 +38,7 @@ class InfoMixin(object):
     Class = None
 
     default_kwargs = {'name': '', 'datatype': None, 'handler': None,
-                      'minOccurs': None, 'maxOccurs': None, 'attribute': None}
+                      'minOccurs': 0, 'maxOccurs': Unbounded, 'attribute': None}
 
     def make_one(self, **kwargs):
         args = self.default_kwargs.copy()
@@ -54,7 +54,7 @@ def test_constructor_error(self):
         self.assertRaisesRegexp(SchemaError,
                                 'maxOccurs',
                                 self.make_one,
-                                maxOccurs=0)
+                                maxOccurs=0, minOccurs=0)
 
         # This case doesn't really make sense
         self.assertRaisesRegexp(SchemaError,

tox.ini

@@ -1,12 +1,12 @@
 [tox]
-envlist = py27,py33,py34,py35,py36
+envlist = py27,py33,py34,py35,py36,pypy
 
 [testenv]
 commands =
     python setup.py -q test -q
 # without explicit deps, setup.py test will download a bunch of eggs into $PWD
 deps =
-     zope.testrunner
+     .[test]
 
 [testenv:coverage]
 basepython =