// Return value of attribute with tuple indexing
public TypedValue ValueNth(CodeValue attribute, NumberValue index, PointerValue lookup)
{
var row = lookup.Value as DataRow;
Logger.Assert(row != null, "lookup is not row");
return(row.ValueOffset(attribute.AsEval, (int)index.Value, OffsetModes.Absolute));
}
// Return ordinal as scalar
public NumberValue OrdinalGroup(PointerValue lookup)
{
var row = lookup.Value as DataRow;
Logger.Assert(row != null, "lookup is not row");
return(row.Ordinal(true));
}
// Invoke a defined function with required argument in scope
// If folded, applies an offset to get the right accumulator
public TypedValue Invoke(CodeValue funcarg, PointerValue accblkarg, NumberValue accbasarg, TypedValue[] valargs)
{
Logger.WriteLine(3, "Invoke {0} accbase={1} ({2})", funcarg, accbasarg, String.Join(",", valargs.Select(a => a.ToString()).ToArray()));
// wrap raw value with evaluator
var expr = funcarg.Value as ExpressionEval;
Logger.Assert(expr != null, "invoke eval");
var args = DataRow.CreateNonTuple(expr.Lookup, valargs);
TypedValue ret;
if (expr.HasFold)
{
var accblk = accblkarg.Value as AccumulatorBlock;
var accbase = (int)accbasarg.Value;
ret = expr.EvalHasFold(args, accblk, accbase);
}
else
{
ret = expr.EvalOpen(args);
}
// If the return value is an unresolved sql table then resolve it now
// before exiting the lookup scope (which it may need)
if (ret is RelationValue && !(ret.AsTable() is DataTableLocal))
{
ret = RelationValue.Create(DataTableLocal.Convert(ret.AsTable(), args, expr.Evaluator));
}
Logger.WriteLine(3, "[Inv {0}]", ret);
return(ret);
}
// Return rank of attribute with tuple indexing
public TypedValue Rank(CodeValue attribute, NumberValue index, PointerValue lookup)
{
var row = lookup.Value as DataRow;
Logger.Assert(row != null, "lookup is not row");
var value = attribute.AsEval.EvalOpen(row);
var offset = row.Heading.FindIndex(attribute.AsEval.Name);
return(NumberValue.Create(index.Value + 1));
}
// Fold an operation and one argument over a set of tuples
public TypedValue Fold(PointerValue accblkarg, NumberValue accidarg, TypedValue defarg, CodeValue expr)
{
Logger.WriteLine(3, "Fold n={0} def={1} expr={2}", accidarg, defarg, expr);
var accblock = accblkarg.Value as AccumulatorBlock;
var accid = (int)accidarg.Value;
var accum = accblock[accid] ?? defarg;
accblock[accid] = expr.AsEval.EvalIsFolded(null, accblock[accid]);
Logger.WriteLine(3, "[Fold {0}]", accblock[accid]);
return(accblock[accid]);
}
// Invoke a do block with its own scope level
public TypedValue DoBlock(CodeValue exprarg, PointerValue accblkarg)
{
Logger.WriteLine(3, "DoBlock {0}", exprarg);
_catvars = _catvars.PushScope();
var accblk = accblkarg.Value as AccumulatorBlock;
var expr = exprarg.Value as ExpressionEval;
var ret = expr.Evaluator.Exec(exprarg.Value.Code, null, null, accblk);
// If the return value is an unresolved sql table then resolve it now
// before exiting the local variable scope (which it may need)
if (ret is RelationValue && !(ret.AsTable() is DataTableLocal))
{
ret = RelationValue.Create(DataTableLocal.Convert(ret.AsTable()));
}
_catvars = _catvars.PopScope();
Logger.WriteLine(3, "[Do {0}]", ret);
return(ret);
}
public TypedValue Fold2(TypedValue defarg, CodeValue expr, PointerValue accblkarg, NumberValue accidarg)
{
return(null);
}
static PointerValue()
{
Default = new PointerValue {
Value = new byte[0]
};
}
// Evaluation engine for ByteCode
TypedValue Run(ByteCode bcode, TypedValue aggregate, AccumulatorBlock accblock)
{
TypedValue retval = null;
var reader = PersistReader.Create(bcode.bytes);
while (reader.More)
{
var opcode = reader.ReadOpcode();
switch (opcode)
{
// Known literal, do not translate into value
case Opcodes.LDVALUE:
PushStack(reader.ReadValue());
break;
// Known catalog variable, look up value
//case Opcodes.LDCAT:
// var catnam = reader.ReadString();
// var catval = CatVars.GetValue(catnam);
// Logger.Assert(catval != null, $"{opcode}:{catnam}");
// if (catval.DataType is DataTypeCode)
// catval = this.Exec((catval as CodeValue).Value.Code);
// _stack.Push(catval);
// break;
// Catalog variable, look up value (could be code)
case Opcodes.LDCAT:
var catnam = reader.ReadString();
var catval = CatVars.GetValue(catnam);
Logger.Assert(catval != null, $"{opcode}:{catnam}");
_stack.Push(catval);
break;
// Catalog variable, must be code, evaluate
case Opcodes.LDCATV:
var ctvnam = reader.ReadString();
var ctvval = CatVars.GetValue(ctvnam) as CodeValue;
Logger.Assert(ctvval != null, $"{opcode}:{ctvnam}");
_stack.Push(this.Exec((ctvval as CodeValue).Value.Code));
break;
// Catalog variable, must be code, as code value
case Opcodes.LDCATR:
var ctrnam = reader.ReadString();
var ctrval = CatVars.GetValue(ctrnam) as CodeValue;
Logger.Assert(ctrval != null, $"{opcode}:{ctrnam}");
PushStack(CodeValue.Create(ExpressionEval.Create(this, ctrval.Value)));
break;
// Load value obtained using lookup by name
case Opcodes.LDFIELD:
var fldval = TypedValue.Empty;
var fldnam = reader.ReadString();
var fldok = LookupValue(fldnam, ref fldval);
Logger.Assert(fldok, $"{opcode}:{fldnam}");
PushStack(fldval);
break;
// Load aggregate value or use specified start value if not available
case Opcodes.LDAGG:
var aggval = reader.ReadValue();
PushStack(aggregate ?? aggval);
break;
// load accumulator by index, or fixed value if not available
case Opcodes.LDACC:
var accnum = reader.ReadInteger();
var accval = reader.ReadValue();
PushStack(accblock == null ? accval : accblock[accnum]);
break;
// Load a segment of code for later call, with this evaluator packaged in
case Opcodes.LDSEG:
var segexp = reader.ReadExpr();
var segval = CodeValue.Create(ExpressionEval.Create(this, segexp));
PushStack(segval);
break;
case Opcodes.LDLOOKUP:
var lkpobj = PointerValue.Create(_lookups.Peek() as object);
PushStack(lkpobj);
break;
case Opcodes.LDACCBLK:
var acbobj = PointerValue.Create(accblock as object);
PushStack(acbobj);
break;
case Opcodes.LDCOMP:
var cmpudt = _stack.Pop() as UserValue;
var cmpval = cmpudt.GetComponentValue(reader.ReadString());
PushStack(cmpval);
break;
case Opcodes.LDFIELDT:
var fdttup = _stack.Pop() as TupleValue;
var fdtval = fdttup.GetFieldValue(reader.ReadString());
PushStack(fdtval);
break;
// Call a function, fixed or variable arg count
case Opcodes.CALL:
case Opcodes.CALLV:
case Opcodes.CALLVT:
var calname = reader.ReadString();
var calmeth = typeof(Builtin).GetMethod(calname);
var calnargs = reader.ReadByte();
var calnvargs = reader.ReadByte();
var calargs = new object[calnargs];
var calargx = calargs.Length - 1;
if (opcode == Opcodes.CALLV)
{
var vargs = new CodeValue[calnvargs];
for (var j = vargs.Length - 1; j >= 0; --j)
{
vargs[j] = _stack.Pop() as CodeValue;
}
calargs[calargx--] = vargs;
}
else if (opcode == Opcodes.CALLVT)
{
var vargs = new TypedValue[calnvargs];
for (var j = vargs.Length - 1; j >= 0; --j)
{
vargs[j] = _stack.Pop() as TypedValue;
}
calargs[calargx--] = vargs;
}
for (; calargx >= 0; --calargx)
{
calargs[calargx] = _stack.Pop();
}
var ret = calmeth.Invoke(_builtin, calargs) as TypedValue;
_stack.Push(ret);
//if (ret.DataType != DataTypes.Void)
// _stack.Push(ret);
break;
case Opcodes.EOS:
retval = _stack.Pop();
//retval = (_stack.Count > 0) ? _stack.Pop() : VoidValue.Void;
break;
default:
throw new NotImplementedException(opcode.ToString());
}
}
if (retval == null)
{
retval = _stack.Pop();
}
//Logger.Assert(retval != null, "stack");
return(retval);
}