private void ATSIGN()
{
DataNeeds(1);
Check(0, SymbolType.STRING);
var varname = DATA.Pop().Value.ToString();
if (SYMTAB.ExistsEntry(varname))
{
var ent = SYMTAB.RetrieveEntry(varname);
DATA.Push(ent);
}
else
{
throw new Exception($"No entry in symbol table called {varname}");
}
}