public ResolverValue ExecuteScalar(IActionQueryHost <ResolverValue> host, int _hardlimit = -1)
{
var r = Execute(host, _hardlimit);
if (r != null)
{
return(r[r.Length - 1]);
}
else
{
return(new ResolverValue());
}
}
public ResolverValue[] Execute(IActionQueryHost <ResolverValue> host, int hardlimit = -1)
{
int pc = 0, i;
int _hardlimit = hardlimit;
Stack <ResolverValue> _datastack = new Stack <ResolverValue>();
//List<ResolverValue> _args = new List<ResolverValue>();
ResolverValue[] _args = new ResolverValue[_MaxArgs];
ResolverValue val;
Instruction instr = Instruction.Empty;
if (host == null)
{
throw new ActionQueryException <ResolverValue>("No host given to Execute", Instruction.Empty, null, 0);
}
IActionQueryHostControl <ResolverValue> tracer = null;
if (host is IActionQueryHostControl <ResolverValue> tr)
{
if (tr.StartTrace(_program))
{
tracer = tr;
}
}
try {
while (pc < _program.Length)
{
instr = _program[pc];
if (_hardlimit == 0)
{
throw new ActionQueryException <ResolverValue>($"Hard limit {hardlimit} has been reached and the program has been stopped.", instr, _datastack.ToArray(), pc);
}
if (_hardlimit > 0)
{
_hardlimit--;
}
if (_datastack.Count < instr.ArgumentsCount)
{
throw new ActionQueryException <ResolverValue>("Stack underflow", instr, _datastack.ToArray(), pc);
}
else if (instr.ArgumentsCount > _MaxArgs)
{
throw new ActionQueryException <ResolverValue>("Too many arguments, up to _MaxArgs(def:16) are supported.", instr, _datastack.ToArray(), pc);
}
for (i = instr.ArgumentsCount - 1; i >= 0; i--)
{
_args[i] = _datastack.Pop();
}
if (tracer != null)
{
if (!tracer.Step(pc, instr, _args.Take(instr.ArgumentsCount).ToArray(), _datastack))
{
return(null);
}
}
// The PC should be incremented after performing the instruction.
switch (instr.Operation)
{
case Instructions.Call:
if (instr.Operand is string s)
{
val = host.CallProc(s, _args.Take(instr.ArgumentsCount).ToArray());
_datastack.Push(val);
}
else
{
throw new ActionQueryException <ResolverValue>("Call requires string operand.", instr, _datastack.ToArray(), pc);
}
pc++;
continue;
case Instructions.Jump:
if (instr.Operand is int x)
{
if (x >= 0 && x < _program.Length)
{
pc = x;
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Jump out of boundaries.", instr, _datastack.ToArray(), pc);
}
}
else
{
throw new ActionQueryException <ResolverValue>("Jump has invalid operand.", instr, _datastack.ToArray(), pc);
}
case Instructions.JumpIfNot:
if (instr.Operand is int y)
{
if (y >= 0 && y < _program.Length)
{
if (instr.ArgumentsCount > 0)
{
val = _args[0];
if (host.IsTruthyOrFalsy(val))
{
pc++;
continue;
}
else
{
pc = y;
continue;
}
}
else
{
throw new ActionQueryException <ResolverValue>("Not enough arguments for JumpIfNot.", instr, _datastack.ToArray(), pc);
}
}
else
{
throw new ActionQueryException <ResolverValue>("Jump out of boundaries.", instr, _datastack.ToArray(), pc);
}
}
else
{
throw new ActionQueryException <ResolverValue>("Jump has invalid operand.", instr, _datastack.ToArray(), pc);
}
case Instructions.NoOp:
pc++;
continue;
case Instructions.PushBool:
if (instr.Operand is bool)
{
_datastack.Push(host.FromBool((bool)instr.Operand));
pc++;
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Invalid operand type.", instr, _datastack.ToArray(), pc);
}
case Instructions.PushDouble:
if (instr.Operand is double)
{
_datastack.Push(host.FromDouble((double)instr.Operand));
pc++;
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Invalid operand type.", instr, _datastack.ToArray(), pc);
}
case Instructions.PushInt:
if (instr.Operand is int)
{
_datastack.Push(host.FromInt((int)instr.Operand));
pc++;
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Invalid operand type.", instr, _datastack.ToArray(), pc);
}
case Instructions.PushNull:
pc++;
_datastack.Push(host.FromNull());
continue;
case Instructions.PushParam:
if (instr.Operand is string)
{
pc++;
val = host.EvalParam(instr.Operand as string);
_datastack.Push(val);
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Invalid operand type.", instr, _datastack.ToArray(), pc);
}
case Instructions.PushVar:
if (instr.Operand is string varname)
{
pc++;
val = host.GetVar(varname);
_datastack.Push(val);
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Invalid operand type.", instr, _datastack.ToArray(), pc);
}
case Instructions.PullVar:
if (instr.Operand is string pullvarname)
{
pc++;
if (instr.ArgumentsCount > 1)
{
throw new ActionQueryException <ResolverValue>("Too many arguments.", instr, _datastack.ToArray(), pc);
}
if (instr.ArgumentsCount < 1)
{
throw new ActionQueryException <ResolverValue>("Not enough arguments.", instr, _datastack.ToArray(), pc);
}
val = host.SetVar(pullvarname, _args.FirstOrDefault());
_datastack.Push(val);
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Invalid operand type.", instr, _datastack.ToArray(), pc);
}
case Instructions.PushString:
if (instr.Operand is string)
{
pc++;
_datastack.Push(host.FromString((string)instr.Operand));
continue;
}
else
{
throw new ActionQueryException <ResolverValue>("Invalid operand type.", instr, _datastack.ToArray(), pc);
}
case Instructions.Dump:
pc++;
continue;
default:
throw new ActionQueryException <ResolverValue>("Unsupported instruction.", instr, _datastack.ToArray(), pc);
}
}
// Execution finished
if (_datastack.Count > 0)
{
return(_datastack.ToArray());
}
else
{
return(null);
}
} catch (ActionQueryException <ResolverValue> ex) {
throw ex;
} catch (Exception ex) {
throw new ActionQueryException <ResolverValue>("Exception in the ActionQuery's host:" + ex.Message, instr, _datastack.ToArray(), pc, ex);
}
}