- express most of the orm.util functions in terms of the inspection system

- modify inspection system:
	1. raise a new exception for any case where the inspection
        context can't be returned.  this supersedes the "not mapped"
        errors.
        2. don't configure mappers on a mapper inspection.  this allows
        the inspectors to be used during mapper config time.  instead,
        the mapper configures on "with_polymorphic_selectable" now,
        which is needed for all queries
- add a bunch of new "is_XYZ" attributes to inspectors
- finish making the name change of "compile" -> "configure", for some reason
this was only done partially

1 files changed, 19 insertions, 9 deletions

diff --git a/lib/sqlalchemy/inspection.py b/lib/sqlalchemy/inspection.py
index 91f222f69..8b0a751ad 100644
--- a/lib/sqlalchemy/inspection.py
+++ b/lib/sqlalchemy/inspection.py
@@ -7,7 +7,7 @@
 """Base inspect API.
 
 :func:`.inspect` provides access to a contextual object
-regarding a subject.   
+regarding a subject.
 
 Various subsections of SQLAlchemy,
 such as the :class:`.Inspector`, :class:`.Mapper`, and
@@ -16,21 +16,28 @@ so that they may return a context object given a certain kind
 of argument.
 """
 
-from . import util
+from . import util, exc
 _registrars = util.defaultdict(list)
 
-def inspect(subject):
+def inspect(subject, raiseerr=True):
     type_ = type(subject)
     for cls in type_.__mro__:
         if cls in _registrars:
             reg = _registrars[cls]
-            break
+            ret = reg(subject)
+            if ret is not None:
+                break
     else:
-        raise exc.InvalidRequestError(
-                "No inspection system is "
-                "available for object of type %s" % 
-                type_)
-    return reg(subject)
+        reg = ret = None
+
+    if raiseerr and (
+            reg is None or ret is None
+        ):
+        raise exc.NoInspectionAvailable(
+            "No inspection system is "
+            "available for object of type %s" %
+            type_)
+    return ret
 
 def _inspects(*types):
     def decorate(fn_or_cls):
@@ -42,3 +49,6 @@ def _inspects(*types):
             _registrars[type_] = fn_or_cls
         return fn_or_cls
     return decorate
+
+def _self_inspects(*types):
+    _inspects(*types)(lambda subject:subject)
\ No newline at end of file