private enum PredEnum { session, table, execproc, selproc } // table and view are treated identically
#if persistent
public void SetPersistent (Term t)
{
Term pred = null;
Term db_info = null; // table( <name>) or procedure( <name>, <executable/selectable>)
bool isTable = false;
bool isExec = false; // executable stored procedure (as opposed to selectable)
Term dbEntity = null;
DbLogin dbLogin = null;
ArrayList args = null;
PredEnum predType;
t.IsPacked = false;
if (t != null) args = t.ArgumentsToArrayList (false);
//for (int i = 0; i < args.Count; i++) Console.WriteLine ("args [{0}] = {1}", i, args [i]);
bool OK =
t != null &&
(args.Count == 2 || args.Count == 5) &&
(pred = (Term)args [0]).Arity == 2 &&
pred.Functor == SLASH &&
pred.Arg (0).IsAtom &&
pred.Arg (1).IsInteger;
if (!OK)
IO.Error ("Bad first argument '{0}' for persistent( <predicate>/<arity>, ...)", t.Arg (0));
OK =
(db_info = (Term)args [1]) != null &&
( (isTable = (db_info.Functor == "table" || db_info.Functor == "view")) ||
db_info.Functor == "procedure" ||
db_info.Functor == "proc") &&
db_info.Arity > 0 &&
( (dbEntity = db_info.Arg (0)).IsAtom || dbEntity.IsString );
if (!OK)
IO.Error ("Bad second argument '{0}' for persistent( ..., table/view/procedure(...))", db_info);
if (isTable)
{
if (db_info.Arity != 1)
IO.Error ("Bad second argument '{0}' for persistent( ..., table/view( <db_entity_name>))", db_info);
predType = PredEnum.table;
}
else
{
string invocation;
OK = (db_info.Arity == 2) && // procedure( <name>, <executable/selectable>)
( (isExec = ((invocation = db_info.Arg (1).Functor) == "executable" || invocation == "exec")) ||
invocation == "selectable" || invocation == "select" );
if (!OK)
IO.Error ("Bad second argument '{0}' for persistent( ..., procedure( <db_entity_name>, [selectable|executable]))", t.Arg (1));
predType = isExec ? PredEnum.execproc : PredEnum.selproc;
}
string functor = pred.Arg (0).Functor;
int arity = Convert.ToInt32 (pred.Arg (1).Functor);
string index = Term.Key (functor, arity);
if (predefineds [index] != null)
IO.Error ("Predefined predicate '{0}/{1}' cannot be declared as persistent", functor, arity);
if (args.Count == 5)
{
for (int i = 2; i <= 4; i++)
if (!(((Term)args [i]).IsAtom || ((Term)args [i]).IsString))
IO.Error ("Argument '{0}' not an atom or string", (Term)args [i]);
dbLogin = new DbLogin (((Term)args [2]).Functor, ((Term)args [3]).Functor, ((Term)args [4]).Functor);
}
PredicateDescr pd = this [index];
if (pd != null) // apparently already defined
{
string definingFile = (pd.DefiningFile == Globals.ConsultFileName) ? "this file" : pd.DefiningFile;
if (!(pd is PersistentPredDescr))
IO.Error ("Predicate '{0}/{1}' cannot be declared as persistent (predicate defined in {2})", functor, arity, definingFile);
}
pd = SetClauseList (predType, functor, arity, null);
((PersistentPredDescr)pd).DbEntity = dbEntity.Functor;
((PersistentPredDescr)pd).DbLogin = dbLogin;
}
public bool SetUndefPredAction(Term t, bool err)
{
Term pred = null;
Term action = null;
ArrayList args = null;
string msg;
bool result = true;
t.IsPacked = false;
if (t != null) args = t.ArgumentsToArrayList(false);
bool OK =
t != null &&
(args.Count == 2) &&
(pred = (Term)args[0]).Arity == 2 &&
pred.Functor == SLASH &&
pred.Arg(0).IsAtom &&
pred.Arg(1).IsInteger;
if (!OK)
{
result = false;
msg = string.Format("Bad first argument '{0}' for undef_pred_action( <predicate>/<arity>, ...)", t.Arg(0));
if (err) PrologIO.Error(msg); else PrologIO.Warning(msg);
}
OK =
(action = (Term)args[1]) != null &&
(action.Functor == "fail" ||
// action.Functor == "succeed" ||
action.Functor == "error" ||
action.Functor == "warning");
if (!OK)
{
result = false;
msg = string.Format("Bad second argument '{0}' for undef_pred_action( ..., fail/succeed/warning)", action);
if (err) PrologIO.Error(msg); else PrologIO.Warning(msg);
}
if (result)
{
string key = Term.Key(pred.Arg(0).Functor, pred.Arg(1).Functor);
actionWhenUndefined[key] = (UndefAction)Enum.Parse(typeof(UndefAction), action.Functor, false);
}
return result;
}