public static void RemoveAt(this MathList self, ref MathListIndex index)
{
index ??= MathListIndex.Level0Index(0);
if (index.AtomIndex > self.Atoms.Count)
{
throw new IndexOutOfRangeException($"Index {index.AtomIndex} is out of bounds for list of size {self.Atoms.Count}");
}
switch (index.SubIndexType)
{
case MathListSubIndexType.None:
self.RemoveAt(index.AtomIndex);
break;
case var _ when index.SubIndex is null:
throw new InvalidCodePathException("index.SubIndex is null despite non-None subindex type");
case MathListSubIndexType.BetweenBaseAndScripts:
var currentAtom = self.Atoms[index.AtomIndex];
if (currentAtom.Subscript.IsEmpty() && currentAtom.Superscript.IsEmpty())
{
throw new SubIndexTypeMismatchException(index);
}
var downIndex = index.LevelDown();
if (downIndex is null)
{
throw new InvalidCodePathException("downIndex is null");
}
if (index.AtomIndex > 0 &&
self.Atoms[index.AtomIndex - 1] is MathAtom previous &&
previous.Subscript.IsEmpty() &&
previous.Superscript.IsEmpty() &&
previous switch
{
Atoms.BinaryOperator _ => false,
Atoms.UnaryOperator _ => false,
Atoms.Relation _ => false,
Atoms.Punctuation _ => false,
Atoms.Space _ => false,
_ => true
})
{
previous.Superscript.Append(currentAtom.Superscript);
previous.Subscript.Append(currentAtom.Subscript);
self.RemoveAt(index.AtomIndex);
// it was in the nucleus and we removed it, get out of the nucleus and get in the nucleus of the previous one.
index = downIndex.Previous is MathListIndex downPrev
? downPrev.LevelUpWithSubIndex(MathListSubIndexType.BetweenBaseAndScripts, MathListIndex.Level0Index(1))
: downIndex;
break;
}
// insert placeholder since we couldn't place the scripts in previous atom
var insertionAtom = LaTeXSettings.Placeholder;
insertionAtom.Subscript.Append(currentAtom.Subscript);
insertionAtom.Superscript.Append(currentAtom.Superscript);
self.RemoveAt(index.AtomIndex);
index = downIndex;
self.InsertAndAdvance(ref index, insertionAtom, MathListSubIndexType.None);
index = index.Previous ?? throw new InvalidCodePathException("Cannot go back after insertion?");
return;
public void TestRemoveAtomAtIndex()
{
var list = new MathList();
var atom = MathAtoms.Placeholder;
var atom2 = MathAtoms.Times;
list.Add(atom);
list.Add(atom2);
Assert.Equal(2, list.Count);
list.RemoveAt(0);
Assert.Single(list);
Assert.Equal(atom2, list[0]);
Assert.Throws <ArgumentOutOfRangeException>(() => list.RemoveAt(1));
Assert.Throws <ArgumentOutOfRangeException>(() => list.RemoveAt(2));
}
