Initial commit. Still building up the env and some parsing code.

python/packages/sqlobject/constraints.py

@@ -0,0 +1,63 @@
+"""
+Constraints
+"""
+
+class BadValue(ValueError):
+
+    def __init__(self, desc, obj, col, value, *args):
+        self.desc = desc
+        self.col = col
+
+        # I want these objects to be garbage-collectable, so
+        # I just keep their repr:
+        self.obj = repr(obj)
+        self.value = repr(value)
+        fullDesc = "%s.%s %s (you gave: %s)" \
+                   % (obj, col.name, desc, value)
+        ValueError.__init__(self, fullDesc, *args)
+
+def isString(obj, col, value):
+    if not isinstance(value, str):
+        raise BadValue("only allows strings", obj, col, value)
+
+def notNull(obj, col, value):
+    if value is None:
+        raise BadValue("is defined NOT NULL", obj, col, value)
+
+def isInt(obj, col, value):
+    if not isinstance(value, (int, long)):
+        raise BadValue("only allows integers", obj, col, value)
+
+def isFloat(obj, col, value):
+    if not isinstance(value, (int, long, float)):
+        raise BadValue("only allows floating point numbers", obj, col, value)
+
+def isBool(obj, col, value):
+    if not isinstance(value, bool):
+        raise BadValue("only allows booleans", obj, col, value)
+
+class InList:
+
+    def __init__(self, l):
+        self.list = l
+
+    def __call__(self, obj, col, value):
+        if value not in self.list:
+            raise BadValue("accepts only values in %s" % repr(self.list),
+                           obj, col, value)
+
+class MaxLength:
+
+    def __init__(self, length):
+        self.length = length
+
+    def __call__(self, obj, col, value):
+        try:
+            length = len(value)
+        except TypeError:
+            raise BadValue("object does not have a length",
+                           obj, col, value)
+        if length > self.length:
+            raise BadValue("must be shorter in length than %s"
+                           % self.length,
+                           obj, col, value)