/*++
Copyright (c) 2010 Microsoft Corporation

Module Name:

    dl_rewriter.cpp

Abstract:

    <abstract>

Author:

    Nikolaj Bjorner (nbjorner) 2010-08-10

Revision History:

--*/

#include "ast/rewriter/dl_rewriter.h"
    
    br_status dl_rewriter::mk_app_core(
        func_decl * f, unsigned num_args, expr* const* args, expr_ref& result) {
        ast_manager& m = result.get_manager();
        uint64_t v1, v2;
        switch(f->get_decl_kind()) {
        case datalog::OP_DL_LT:
            if (m_util.is_numeral_ext(args[0], v1) &&
                m_util.is_numeral_ext(args[1], v2)) {
                result = m.mk_bool_val(v1 < v2);
                return BR_DONE;
            }
            // x < x <=> false
            if (args[0] == args[1]) {
                result = m.mk_false();
                return BR_DONE;
            }
            // x < 0 <=> false
            if (m_util.is_numeral_ext(args[1], v2) && v2 == 0) {
                result = m.mk_false();
                return BR_DONE;
            }
            // 0 < x <=> 0 != x
            if (m_util.is_numeral_ext(args[1], v1) && v1 == 0) {
                result = m.mk_not(m.mk_eq(args[0], args[1]));
                return BR_DONE;
            }
            break;
            
        default:
            break;
        }
        return BR_FAILED;
    }