Sized brackets

[Happypig375]

Is your feature request related to a problem? Please describe.
Currently, the editor cannot create and edit bracket pairs that scale to the size of the formulae inside. This will be beneficial as bracket-counting will no longer be required.

Describe the solution you'd like
Being able to point MathListIndices to Inner atoms. (e.g. \big(, \big))

Describe alternatives you've considered
Not implementing. Traditional bracket pairs still have the advantage of not requiring to be balanced.

Difficulty: How difficult would it be? (Trivial, Very Easy, Easy, Moderate, Hard, Very Hard, Tedious, Backbreaking)
Hard. Editing inner atoms is tricky because the ambiguity of editing delimiters of Inner atoms.

[charlesroddie]

I doubt that sizing brackets would involve editing delimiters, or specifying their size explicitly.

Entering ( should give the LaTeX-equivalent of \left( \placeholder \right), or whatever equates to Atom.Bracketed(Bracket.Ordinary, Atom.Placeholder). Brackets will then size automatically.

[Happypig375]

What about writing ranges like [10, 30)?

[charlesroddie]

Interesting. I think two options: (below in pseudoTeX)

1. As Office Equation Editor does: when [10,30 has been entered it is stored as ordary atoms ([10,30), but when the final right bracket is entered it gets matched (\left[ 10,30 \right)).
2. As MathQuill: when [ is entered it is actually \left[ \placeholder \rightGray], and before the ) is entered it is \left[ 10, 30 \rightGray], and then entering ) overwrites the rightGray] with right) giving \left[ 10, 30 \right).

[charlesroddie]

Either way we need to allow matched brackets, so that is the first step.

MathKeyboardInput.BothRoundBrackets should give matched brackets.

Currently if you initialize with:

let prevMathList = CSharpMath.Atoms.MathLists.FromString(@"\left( \frac{a}{b} \right)")
for atom in prevMathList do
    keyboard.MathList.Add(atom)
    keyboard.InsertionIndex <- MathListIndex.Level0Index keyboard.MathList.Count

then display is fine, but you can't get inside the brackets using arrow keys, and clicking inside gives an error:

System.ArgumentException: 'ListDisplay LinePosition Regular inside an ListDisplay - shouldn't happen
Parameter name: self

[Happypig375]

Blocked on #117 and #124.