///// <summary> Performs a left fold on the array: +, 0, [1, 2, 3] => (((0 + 1) + 2) + 3) </summary>
private static Val FoldLeft(Func <Val, Val, Val> fn, Val baseElement, VarArgs args)
{
var result = baseElement;
var elements = args.ToNativeList();
for (int i = 0, len = elements.Count; i < len; i++)
{
result = fn(result, elements[i]);
}
return(result);
}
///// <summary> Performs a right fold on the array: +, 0, [1, 2, 3] => (1 + (2 + (3 + 0))) </summary>
private static Val FoldRight(Func <Val, Val, Val> fn, Val baseElement, VarArgs args)
{
var result = baseElement;
var elements = args.ToNativeList();
for (int i = elements.Count - 1; i >= 0; i--)
{
result = fn(elements[i], result);
}
return(result);
}
//
//
// dotnet interop
public static Val DotDot(Context _, VarArgs args)
{
var arglist = args.ToNativeList().SelectMany(SplitSymbol).ToList();
var gotone = arglist.Count > 0;
if (!gotone)
{
return(Val.NIL);
}
int i = 0;
var current = arglist[i++];
do
{
var nextSymbol = TakeNextSymbolOrNull();
var nonSymbols = TakeNonSymbols().ToList();
current = TryReflectionStep(current, nextSymbol, nonSymbols);
} while (i < arglist.Count);
return(current);
Symbol TakeNextSymbolOrNull()
{
var results = TakeSymbols(true).Take(1);
return(results.FirstOrDefault().AsSymbolOrNull);
}
IEnumerable <Val> TakeNonSymbols()
{
return(TakeSymbols(false));
}
IEnumerable <Val> TakeSymbols(bool expected)
{
while (i < arglist.Count)
{
var next = arglist[i];
if (next.IsSymbol == expected)
{
i++;
yield return(next);
}
else
{
break;
}
}
}
}