morro

sqlalchemy/sql/functions.py

@@ -0,0 +1,104 @@
+from sqlalchemy import types as sqltypes
+from sqlalchemy.sql.expression import (
+    ClauseList, Function, _literal_as_binds, text, _type_from_args
+    )
+from sqlalchemy.sql import operators
+from sqlalchemy.sql.visitors import VisitableType
+
+class _GenericMeta(VisitableType):
+    def __call__(self, *args, **kwargs):
+        args = [_literal_as_binds(c) for c in args]
+        return type.__call__(self, *args, **kwargs)
+
+class GenericFunction(Function):
+    __metaclass__ = _GenericMeta
+
+    def __init__(self, type_=None, args=(), **kwargs):
+        self.packagenames = []
+        self.name = self.__class__.__name__
+        self._bind = kwargs.get('bind', None)
+        self.clause_expr = ClauseList(
+                operator=operators.comma_op,
+                group_contents=True, *args).self_group()
+        self.type = sqltypes.to_instance(
+            type_ or getattr(self, '__return_type__', None))
+
+class AnsiFunction(GenericFunction):
+    def __init__(self, **kwargs):
+        GenericFunction.__init__(self, **kwargs)
+
+class ReturnTypeFromArgs(GenericFunction):
+    """Define a function whose return type is the same as its arguments."""
+    
+    def __init__(self, *args, **kwargs):
+        kwargs.setdefault('type_', _type_from_args(args))
+        GenericFunction.__init__(self, args=args, **kwargs)
+
+class coalesce(ReturnTypeFromArgs):
+    pass
+
+class max(ReturnTypeFromArgs):
+    pass
+
+class min(ReturnTypeFromArgs):
+    pass
+
+class sum(ReturnTypeFromArgs):
+    pass
+
+class now(GenericFunction):
+    __return_type__ = sqltypes.DateTime
+
+class concat(GenericFunction):
+    __return_type__ = sqltypes.String
+    def __init__(self, *args, **kwargs):
+        GenericFunction.__init__(self, args=args, **kwargs)
+
+class char_length(GenericFunction):
+    __return_type__ = sqltypes.Integer
+
+    def __init__(self, arg, **kwargs):
+        GenericFunction.__init__(self, args=[arg], **kwargs)
+
+class random(GenericFunction):
+    def __init__(self, *args, **kwargs):
+        kwargs.setdefault('type_', None)
+        GenericFunction.__init__(self, args=args, **kwargs)
+
+class count(GenericFunction):
+    """The ANSI COUNT aggregate function.  With no arguments, emits COUNT \*."""
+
+    __return_type__ = sqltypes.Integer
+
+    def __init__(self, expression=None, **kwargs):
+        if expression is None:
+            expression = text('*')
+        GenericFunction.__init__(self, args=(expression,), **kwargs)
+
+class current_date(AnsiFunction):
+    __return_type__ = sqltypes.Date
+
+class current_time(AnsiFunction):
+    __return_type__ = sqltypes.Time
+
+class current_timestamp(AnsiFunction):
+    __return_type__ = sqltypes.DateTime
+
+class current_user(AnsiFunction):
+    __return_type__ = sqltypes.String
+
+class localtime(AnsiFunction):
+    __return_type__ = sqltypes.DateTime
+
+class localtimestamp(AnsiFunction):
+    __return_type__ = sqltypes.DateTime
+
+class session_user(AnsiFunction):
+    __return_type__ = sqltypes.String
+
+class sysdate(AnsiFunction):
+    __return_type__ = sqltypes.DateTime
+
+class user(AnsiFunction):
+    __return_type__ = sqltypes.String
+