Add way for report to provide available "choices" for any param

rattail/reporting/reports.py

@@ -97,6 +97,19 @@ class Report(object):
         """
         return self.collect_static_params(**kwargs)
 
+    def get_choices(self, name, session):
+        """
+        Invoke the appropriately-named method, to return a set of "choices" for
+        selection by the user.  Note that ``name`` must correspond to one of
+        the parameter names.
+        """
+        static_name = 'choices_{}'.format(name)
+        if hasattr(self, static_name):
+            return getattr(self, static_name)
+
+        getter = getattr(self, 'get_choices_{}'.format(name))
+        return getter(session)
+
     def make_data(self, session, params, progress=None, **kwargs):
         """
         Should generate and return a dict which contains all relevant data for
@@ -139,7 +152,11 @@ class ReportParam(object):
     Base class for report parameter definitions.
     """
 
+    # TODO: deprecate / remove the `typ` kwarg? (replace w/ `type`)
     def __init__(self, typ=str, required=True, doc="", **kwargs):
+        if 'type' in kwargs:
+            self.type = kwargs.pop('type')
+        else:
             self.type = typ
         self.required = required
         self.__doc__ == doc