internal static void PL_close_query(uintptr_t qid)
{
if (IsValid)
{
SafeNativeMethods.PL_close_query(qid);
}
}
/// <summary>
/// Provide the next solution to the query. Prolog exceptions are mapped to C# exceptions.
/// </summary>
/// <returns>return true if successful and false if there are no (more) solutions.</returns>
/// <remarks>
/// <para>If the query is closed it will be opened. If the last solution was generated the query will be closed.</para>
/// <para>If an exception is thrown while parsing (open) the query the _qid is set to zero.</para>
/// </remarks>
/// <exception cref="PlException">Is thrown if <see href="http://gollem.science.uva.nl/SWI-Prolog/Manual/foreigninclude.html#PL_next_solution()">SWI-Prolog Manual PL_next_solution()</see> returns false </exception>
public bool NextSolution()
{
if (0 == _qid)
{
Check.Require(!string.IsNullOrEmpty(_name), "PlQuery.NextSolution() _name is required");
IntPtr p = LibPl.PL_predicate(_name, _av.Size, _module);
_qid = LibPl.PL_open_query((IntPtr)0, LibPl.PL_Q_CATCH_EXCEPTION, p, _av.A0);
}
int rval = LibPl.PL_next_solution(_qid);
if (0 == rval)
{ // error
uintptr_t ex; // term_t
if ((ex = LibPl.PL_exception(_qid)) > 0)
{
_qid = 0; // to avoid an AccessViolationException on Dispose. E.g. if the query is miss spelled.
var etmp = new PlException(new PlTerm(ex));
etmp.Throw();
}
}
if (rval <= 0)
{
Free(false);
}
return(rval > 0);
}
internal static String PL_atom_wchars(uintptr_t tAtom)
{
// see http://www.mycsharp.de/wbb2/thread.php?threadid=51100
int dummyLen = 0;
return(Marshal.PtrToStringUni(SafeNativeMethods.PL_atom_wchars(tAtom, ref dummyLen)));
}
internal static void PL_close_foreign_frame(uintptr_t fid_t)
{
if (IsValid)
{
SafeNativeMethods.PL_close_foreign_frame(fid_t);
}
}
internal static int PL_get_wchars(uintptr_t term, out string s, uint flags)
{
var dummyLen = 0;
var ps = IntPtr.Zero;
var iRet = SafeNativeMethods.PL_get_wchars(term, ref dummyLen, ref ps, flags);
s = Marshal.PtrToStringUni(ps);
return(iRet);
}
/// <summary>
/// Discards the query, but does not delete any of the data created by the query if discardData is false.
/// It just invalidate qid, allowing for a new PlQuery object in this context.
/// </summary>
/// <remarks>see <see href="http://gollem.science.uva.nl/SWI-Prolog/Manual/foreigninclude.html#PL_cut_query()"/></remarks>
/// <param name="discardData">if true all bindings of the query are destroyed</param>
private void Free(bool discardData)
{
if (_qid > 0 && PlEngine.IsInitialized)
{
try
{
if (discardData)
{
// <"leider werden dann die gebundenen variablen der query wieder frei e.g. in PlCall(goal)"/>
// unfortunately this statement detaches the bound variables of the query e.g. in PlCall(goal)
LibPl.PL_close_query(_qid);
}
else
{
LibPl.PL_cut_query(_qid);
}
}
catch (AccessViolationException ex)
{
TraceAccessViolationException(ex);
}
}
_qid = 0;
}
internal static int PL_get_list(uintptr_t termL, uintptr_t termH, uintptr_t termT)
{
return(SafeNativeMethods.PL_get_list(termL, termH, termT));
}
// LISTS (PlTail)
internal static uintptr_t PL_copy_term_ref(uintptr_t term_t)
{
return(SafeNativeMethods.PL_copy_term_ref(term_t));
}
internal static int PL_is_number(uintptr_t term_t)
{
return(SafeNativeMethods.PL_is_number(term_t));
}
internal static int PL_term_type(uintptr_t t)
{
return(SafeNativeMethods.PL_term_type(t));
}
internal static int PL_get_arg(int index, uintptr_t t, uintptr_t a)
{
return(SafeNativeMethods.PL_get_arg(index, t, a));
}
// Exceptions
// Handling exceptions
internal static uintptr_t PL_exception(uintptr_t qid)
{
return(SafeNativeMethods.PL_exception(qid));
}
/// <summary>
/// Unify t with a textual representation of the C wide-character array s.
/// The type argument defines the Prolog representation and is one of PL_ATOM, PL_STRING, PL_CODE_LIST or PL_CHAR_LIST.
/// </summary>
/// <param name="t1"></param>
/// <param name="type"></param>
/// <param name="wchars"></param>
/// <returns></returns>
internal static int PL_unify_wchars(uintptr_t t1, PlType type, string wchars)
{
return(PL_unify_wchars(t1, type, wchars.Length, wchars));
}
// Testing the type of a term
// all return non zero if condition succeed
internal static int PL_is_variable(uintptr_t term_t)
{
return(SafeNativeMethods.PL_is_variable(term_t));
}
internal static uintptr_t PL_new_functor(uintptr_t atomA, int a)
{
return(SafeNativeMethods.PL_new_functor(atomA, a));
}
internal static void PL_cons_functor_v(uintptr_t term, uintptr_t functor_t, uintptr_t termA0)
{
SafeNativeMethods.PL_cons_functor_v(term, functor_t, termA0);
}
internal static int PL_wchars_to_term(string chars, uintptr_t term)
{
return(SafeNativeMethods.PL_wchars_to_term(chars, term));
}
internal static void PL_put_term(uintptr_t t1, uintptr_t t2)
{
SafeNativeMethods.PL_put_term(t1, t2);
}
// COMPARE
internal static int PL_compare(uintptr_t term1, uintptr_t term2)
{
return(SafeNativeMethods.PL_compare(term1, term2));
}
internal static int PL_get_nil(uintptr_t term_t)
{
return(SafeNativeMethods.PL_get_nil(term_t));
}
internal static int PL_unify(uintptr_t t1, uintptr_t t2)
{
return(SafeNativeMethods.PL_unify(t1, t2));
}
internal static int PL_is_string(uintptr_t term_t)
{
return(SafeNativeMethods.PL_is_string(term_t));
}
internal static int PL_unify_wchars(uintptr_t t1, PlType type, int len, string wchars)
{
Check.Require(type == PlType.PlAtom || type == PlType.PlString || type == PlType.PlCharList || type == PlType.PlCodeList);
return(SafeNativeMethods.PL_unify_wchars(t1, (int)type, len, wchars));
}
internal static int PL_is_float(uintptr_t term_t)
{
return(SafeNativeMethods.PL_is_float(term_t));
}
internal static int PL_raise_exception(uintptr_t exceptionTerm)
{
return(SafeNativeMethods.PL_raise_exception(exceptionTerm));
}
internal static int PL_get_long(uintptr_t term, ref int i)
{
return(SafeNativeMethods.PL_get_long(term, ref i));
}
internal static int PL_get_name_arity(uintptr_t t, ref uintptr_t name, ref int arity)
{
return(SafeNativeMethods.PL_get_name_arity(t, ref name, ref arity));
}
internal static int PL_get_float(uintptr_t term, ref double i)
{
return(SafeNativeMethods.PL_get_float(term, ref i));
}
internal static int PL_is_compound(uintptr_t term_t)
{
return(SafeNativeMethods.PL_is_compound(term_t));
}
internal static int PL_is_atomic(uintptr_t term_t)
{
return(SafeNativeMethods.PL_is_atomic(term_t));
}
