add unit extraction

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

src/api/api_solver.cpp

@@ -347,6 +347,22 @@ extern "C" {
         Z3_CATCH_RETURN(0);
     }
 
+
+    Z3_ast_vector Z3_API Z3_solver_get_units(Z3_context c, Z3_solver s) {
+        Z3_TRY;
+        LOG_Z3_solver_get_units(c, s);
+        RESET_ERROR_CODE();
+        init_solver(c, s);
+        Z3_ast_vector_ref * v = alloc(Z3_ast_vector_ref, *mk_c(c), mk_c(c)->m());
+        mk_c(c)->save_object(v);
+        expr_ref_vector fmls = to_solver_ref(s)->get_units(mk_c(c)->m());
+        for (expr* f : fmls) {
+            v->m_ast_vector.push_back(f);
+        }
+        RETURN_Z3(of_ast_vector(v));
+        Z3_CATCH_RETURN(0);
+    }
+
     static Z3_lbool _solver_check(Z3_context c, Z3_solver s, unsigned num_assumptions, Z3_ast const assumptions[]) {
         for (unsigned i = 0; i < num_assumptions; i++) {
             if (!is_expr(to_ast(assumptions[i]))) {

src/api/dotnet/Solver.cs

@@ -265,6 +265,20 @@ namespace Microsoft.Z3
             }
         }
 
+        /// <summary>
+        /// Currently inferred units.
+        /// </summary>
+        public BoolExpr[] Units
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<BoolExpr[]>() != null);
+
+                ASTVector assertions = new ASTVector(Context, Native.Z3_solver_get_units(Context.nCtx, NativeObject));
+                return assertions.ToBoolExprArray();
+            }
+        }
+
         /// <summary>
         /// Checks whether the assertions in the solver are consistent or not.
         /// </summary>

src/api/python/z3/z3.py

@@ -6369,6 +6369,11 @@ class Solver(Z3PPObject):
         """
         return AstVector(Z3_solver_get_assertions(self.ctx.ref(), self.solver), self.ctx)
 
+    def units(self):
+        """Return an AST vector containing all currently inferred units.
+        """
+        return AstVector(Z3_solver_get_units(self.ctx.ref(), self.solver), self.ctx)
+
     def statistics(self):
         """Return statistics for the last `check()`.
 

src/api/z3_api.h

@@ -6163,6 +6163,13 @@ extern "C" {
     */
     Z3_ast_vector Z3_API Z3_solver_get_assertions(Z3_context c, Z3_solver s);
 
+    /**
+       \brief Return the set of units modulo model conversion.
+
+       def_API('Z3_solver_get_units', AST_VECTOR, (_in(CONTEXT), _in(SOLVER)))
+    */
+    Z3_ast_vector Z3_API Z3_solver_get_units(Z3_context c, Z3_solver s);
+
     /**
        \brief Check whether the assertions in a given solver are consistent or not.