protected override Expression VisitIndex(Index I)
{
I = (Index)base.VisitIndex(I);
// We can only evaluate index expressions with constant integer indices.
if (!I.Indices.All(i => i.IsInteger()))
return I;
// Index a matrix.
Matrix M = I.Target as Matrix;
if (!ReferenceEquals(M, null))
{
switch (I.Indices.Count())
{
case 1: return M[(int)I.Indices.ElementAt(0)];
case 2: return M[(int)I.Indices.ElementAt(0), (int)I.Indices.ElementAt(1)];
}
}
// Index an array.
Array A = I.Target as Array;
if (!ReferenceEquals(A, null))
return Constant.New(A.Value.GetValue(I.Indices.Select(i => (int)i).ToArray()));
return I;
}