add API for creating and attaching simplifiers

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/api/python/z3/z3.py

@@ -8169,6 +8169,64 @@ class ApplyResult(Z3PPObject):
         else:
             return Or([self[i].as_expr() for i in range(len(self))])
 
+#########################################
+#
+# Simplifiers
+#
+#########################################
+
+class Simplifier:
+    """Simplifiers act as pre-processing utilities for solvers.
+    Build a custom simplifier and add it to a solver"""
+
+    def __init__(self, simplifier, ctx=None):
+        self.ctx = _get_ctx(ctx)
+        self.simplifier = None
+        if isinstance(simplifier, SimplifierObj):
+            self.simplifier = simplifier
+        elif isinstance(simplifier, list):
+            simps = [Simplifier(s, ctx) for s in simplifier]
+            self.simplifier = simps[0].simplifier
+            for i in range(1, len(simps)):
+                self.simplifier = Z3_simplifier_and_then(self.ctx.ref(), self.simplifier, simps[i].simplifier)
+            Z3_simplifier_inc_ref(self.ctx.ref(), self.simplifier)
+            return
+        else:
+            if z3_debug():
+                _z3_assert(isinstance(simplifier, str), "simplifier name expected")
+            try:
+                self.simplifier = Z3_mk_simplifier(self.ctx.ref(), str(simplifier))
+            except Z3Exception:
+                raise Z3Exception("unknown simplifier '%s'" % simplifier)
+        Z3_simplifier_inc_ref(self.ctx.ref(), self.simplifier)
+
+    def __deepcopy__(self, memo={}):
+        return Simplifier(self.simplifier, self.ctx)
+
+    def __del__(self):
+        if self.simplifier is not None and self.ctx.ref() is not None and Z3_simplifier_dec_ref is not None:
+            Z3_simplifier_dec_ref(self.ctx.ref(), self.simplifier)
+
+    def using_params(self, *args, **keys):
+        """Return a simplifier that uses the given configuration options"""
+        p = args2params(args, keys, self.ctx)
+        return Simplifier(Z3_simplifier_using_params(self.ctx.ref(), self.simplifier, p.params), self.ctx)
+
+    def add(self, solver):
+        """Return a solver that applies the simplification pre-processing specified by the simplifier"""
+        print(solver.solver)
+        print(self.simplifier)
+        return Solver(Z3_solver_add_simplifier(self.ctx.ref(), solver.solver, self.simplifier), self.ctx)
+
+    def help(self):
+        """Display a string containing a description of the available options for the `self` simplifier."""
+        print(Z3_simplifier_get_help(self.ctx.ref(), self.simplifier))
+
+    def param_descrs(self):
+        """Return the parameter description set."""
+        return ParamDescrsRef(Z3_simplifier_get_param_descrs(self.ctx.ref(), self.simplifier), self.ctx)
+        
+    
 #########################################
 #
 # Tactics

src/api/python/z3/z3types.py

@@ -120,6 +120,12 @@ class TacticObj(ctypes.c_void_p):
     def from_param(obj):
         return obj
 
+class SimplifierObj(ctypes.c_void_p):
+    def __init__(self, simplifier):
+        self._as_parameter_ = simplifier
+
+    def from_param(obj):
+        return obj
 
 class ProbeObj(ctypes.c_void_p):
     def __init__(self, probe):