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;
/// <summary>Inserts <paramref name="atom"/> and modifies <paramref name="index"/> to advance to the next position.</summary> public static void InsertAndAdvance(this MathList self, ref MathListIndex index, MathAtom atom, MathListSubIndexType advanceType) { 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.InsertAtAtomIndexAndAdvance(index.AtomIndex, atom, ref index, advanceType); 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); } if (atom.Subscript.IsNonEmpty() || atom.Superscript.IsNonEmpty()) { throw new ArgumentException("Cannot fuse with an atom that already has a subscript or a superscript"); } atom.Subscript.Append(currentAtom.Subscript); atom.Superscript.Append(currentAtom.Superscript); currentAtom.Subscript.Clear(); currentAtom.Superscript.Clear(); var atomIndex = index.AtomIndex; // Prevent further subindexing inside BetweenBaseAndScripts if (advanceType != MathListSubIndexType.None && index.LevelDown() is MathListIndex levelDown) { index = levelDown.Next; } self.InsertAtAtomIndexAndAdvance(atomIndex + 1, atom, ref index, advanceType); break; case MathListSubIndexType.Degree: case MathListSubIndexType.Radicand: if (!(self.Atoms[index.AtomIndex] is Atoms.Radical radical)) { throw new SubIndexTypeMismatchException(typeof(Atoms.Radical), index); } if (index.SubIndexType == MathListSubIndexType.Degree) { radical.Degree.InsertAndAdvance(ref index.SubIndex, atom, advanceType); } else { radical.Radicand.InsertAndAdvance(ref index.SubIndex, atom, advanceType); } break; case MathListSubIndexType.Numerator: case MathListSubIndexType.Denominator: if (!(self.Atoms[index.AtomIndex] is Atoms.Fraction frac)) { throw new SubIndexTypeMismatchException(typeof(Atoms.Fraction), index); } if (index.SubIndexType == MathListSubIndexType.Numerator) { frac.Numerator.InsertAndAdvance(ref index.SubIndex, atom, advanceType); } else { frac.Denominator.InsertAndAdvance(ref index.SubIndex, atom, advanceType); } break; case MathListSubIndexType.Subscript: self.Atoms[index.AtomIndex].Subscript.InsertAndAdvance(ref index.SubIndex, atom, advanceType); break; case MathListSubIndexType.Superscript: self.Atoms[index.AtomIndex].Superscript.InsertAndAdvance(ref index.SubIndex, atom, advanceType); break; case MathListSubIndexType.Inner: if (!(self.Atoms[index.AtomIndex] is Atoms.Inner inner)) { throw new SubIndexTypeMismatchException(typeof(Atoms.Inner), index); } inner.InnerList.InsertAndAdvance(ref index.SubIndex, atom, advanceType); break; default: throw new SubIndexTypeMismatchException(index); } }