private Expression ReadTerm()
{
Expression r = null;
if (iToken == ExpressionType.DatabaseColumn) {
string name = sToken;
r = new Expression (sTable, sToken);
Read ();
if (iToken == ExpressionType.Open) {
Function f = new Function (dDatabase.GetAlias (name), cChannel);
/*int len = */f.GetArgCount ();
int i = 0;
Read ();
if (iToken != ExpressionType.Close) {
while (true) {
f.SetArgument (i++, ReadOr ());
if (iToken != ExpressionType.Comma) {
break;
}
Read ();
}
}
ReadThis (ExpressionType.Close);
r = new Expression (f);
}
} else if (iToken == ExpressionType.Negate) {
ExpressionType type = iToken;
Read ();
r = new Expression (type, ReadTerm (), null);
} else if (iToken == ExpressionType.Plus) {
Read ();
r = ReadTerm ();
} else if (iToken == ExpressionType.Open) {
Read ();
r = ReadOr ();
if (iToken != ExpressionType.Close) {
throw TracingHelper.Error (TracingHelper.UnexpectedToken, sToken);
}
Read ();
} else if (iToken == ExpressionType.Value) {
r = new Expression (iType, oData);
Read ();
} else if (iToken == ExpressionType.Select) {
r = new Expression (ParseSelect ());
Read ();
} else if (iToken == ExpressionType.Multiply) {
r = new Expression (sTable, null);
Read ();
} else if (iToken == ExpressionType.IfNull || iToken == ExpressionType.Concat) {
ExpressionType type = iToken;
Read ();
ReadThis (ExpressionType.Open);
r = ReadOr ();
ReadThis (ExpressionType.Comma);
r = new Expression (type, r, ReadOr ());
ReadThis (ExpressionType.Close);
} else if (iToken == ExpressionType.CaseWhen) {
ExpressionType type = iToken;
Read ();
ReadThis (ExpressionType.Open);
r = ReadOr ();
ReadThis (ExpressionType.Comma);
Expression thenelse = ReadOr ();
ReadThis (ExpressionType.Comma);
// thenelse part is never evaluated; only init
thenelse = new Expression (type, thenelse, ReadOr ());
r = new Expression (type, r, thenelse);
ReadThis (ExpressionType.Close);
} else if (iToken == ExpressionType.Convert) {
ExpressionType type = iToken;
Read ();
ReadThis (ExpressionType.Open);
r = ReadOr ();
ReadThis (ExpressionType.Comma);
ColumnType t = Column.GetColumnType (sToken);
r = new Expression (type, r, null);
r.SetDataType (t);
Read ();
ReadThis (ExpressionType.Close);
} else if (iToken == ExpressionType.Cast) {
Read ();
ReadThis (ExpressionType.Open);
r = ReadOr ();
TracingHelper.Check (sToken.Equals ("AS"), TracingHelper.UnexpectedToken, sToken);
Read ();
ColumnType t = Column.GetColumnType (sToken);
r = new Expression (ExpressionType.Convert, r, null);
r.SetDataType (t);
Read ();
ReadThis (ExpressionType.Close);
} else if (iToken == ExpressionType.Variable) {
ExpressionType type = iToken;
r = new Expression (null, sToken);
r.Type = type;
string columnType = tTokenizer.GetString ();
if (Column.IsValidDataType (columnType)) {
ColumnType iType = Column.GetColumnType (columnType);
if (iType == ColumnType.VarChar && dDatabase.IsIgnoreCase) {
iType = ColumnType.VarCharIgnoreCase;
}
r.SetDataType (iType);
r.SetArg (null);
} else {
tTokenizer.Back ();
Declare declare = cChannel.GetDeclare (r.ColumnName);
if (declare != null) {
r = declare.Expression;
} else {
throw TracingHelper.Error (TracingHelper.VARIABLE_NOT_DECLARED, sToken);
}
}
Read ();
} else if (iToken == ExpressionType.SquareBracketLeft) {
ReadThis (ExpressionType.SquareBracketLeft);
var t = ReadTerm ();
if (t.Type != ExpressionType.DatabaseColumn) {
throw TracingHelper.Error (TracingHelper.FIELD_OF_TABLE_IS_EXPECTED, /*tTokenizer.GetString()*/ "???");
}
ReadThis (ExpressionType.SquareBracketRight);
return t;
} else {
throw TracingHelper.Error (TracingHelper.UnexpectedToken, sToken);
}
return r;
}
