Trac 14801: Rewrite piecewise functions as symbolic functions

Author: vbraun

src/sage/functions/all.py

@@ -1,4 +1,7 @@
-from piecewise import piecewise, Piecewise
+from sage.misc.lazy_import import lazy_import
+
+lazy_import('sage.functions.piecewise', 'Piecewise')   # deprecated
+lazy_import('sage.functions.piecewise', 'piecewise')
 
 from trig import ( sin, cos, sec, csc, cot, tan,
                    asin, acos, atan,