private static (object value, string error) Evaluator(Expression expression, IMemory state, Options options)
{
object result = null;
string error;
object instance;
(instance, error) = expression.Children[0].TryEvaluate(state, options);
if (error == null)
{
var isInstanceList = false;
IList list = null;
if (FunctionUtils.TryParseList(instance, out IList ilist))
{
isInstanceList = true;
list = ilist;
}
else if (instance is JObject jobj)
{
list = FunctionUtils.Object2KVPairList(jobj);
}
else if (FunctionUtils.ConvertToJToken(instance) is JObject jobject)
{
list = FunctionUtils.Object2KVPairList(jobject);
}
else
{
error = $"{expression.Children[0]} is not a collection or structure object to run foreach";
}
if (error == null)
{
var iteratorName = (string)(expression.Children[1].Children[0] as Constant).Value;
var stackedMemory = StackedMemory.Wrap(state);
result = new List <object>();
for (var idx = 0; idx < list.Count; idx++)
{
var local = new Dictionary <string, object>
{
{ iteratorName, FunctionUtils.AccessIndex(list, idx).value },
};
// the local iterator is pushed as one memory layer in the memory stack
stackedMemory.Push(new SimpleObjectMemory(local));
var(r, e) = expression.Children[2].TryEvaluate(stackedMemory, new Options(options)
{
NullSubstitution = null
});
stackedMemory.Pop();
if (FunctionUtils.IsLogicTrue(r) && e == null)
{
// add if only if it evaluates to true
((List <object>)result).Add(local[iteratorName]);
}
}
if (!isInstanceList)
{
// re-construct object
var jobjResult = new JObject();
foreach (var item in (List <object>)result)
{
FunctionUtils.TryAccessProperty(item, "key", out var keyVal);
FunctionUtils.TryAccessProperty(item, "value", out var val);
jobjResult.Add(keyVal as string, FunctionUtils.ConvertToJToken(val));
}
result = jobjResult;
}
}
}
return(result, error);
}
