/*
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.

Author: Leonardo de Moura
*/
#include <string>
#include "kernel/environment.h"

namespace lean {
/**
   \brief Return true iff the environment \c env contains the following declarations
   in the namespace 'bit'
       b0 : bit
       b1 : bit
   and the following ones in the namespace 'string'
       ascii : bit -> bit -> bit -> bit -> bit -> bit -> bit -> bit -> char
       empty : string
       str   : char -> string -> string
*/
bool has_string_decls(environment const & env);

/**
    \brief Return an expression that encodes the given string using the declarations
    ascii, empty and str.

    \see has_string_decls

    \post *to_string(from_string(s)) == s
*/
expr from_string(std::string const & s);

/**
   \brief If the given expression encodes a string, then convert it back to a string.

   \see from_string
*/
optional<std::string> to_string(expr const & e);

void initialize_string();
void finalize_string();
}