Invalid Latex output for double subscript

[karlwessel]

The LaTeX-output of latexify for something with double subscripts does not compile. For example:

julia> using Latexify

julia> latexify(:(x[1:2][1]); index = :subscript)
L"$x_{:\left( 1, 2 \right)}_{1}$"

The returned Latex does not compile correctly: see http://www.texrendr.com/?eqn=x_%7B%3A%5Cleft(%201%2C%202%20%5Cright)%7D_%7B1%7D.

This issue comes up in ModelingToolkit when indexing sub-arrays (see JuliaSymbolics/Symbolics.jl#1288).

[gustaphe]

Ooh. Tricky one. We could fix it so this outputs the same as @latexify x[1:2, 1], but would that be correct?
Note that after this is sorted, you will run into #315 .

[karlwessel]

I would just add parenthesis around the output for the inner expression, so that Latex knows to what the indices refer:

${x_{:\left( 1, 2 \right)}}_{1}$

[gustaphe]

I misread your comment, but I agreed with the version I read so, my suggestion is

$$\left( x_{1} \right)_{1}$$

See PR #316.

[karlwessel]

Yes, the new output with PR #316 looks good:

julia> latexify(:(x[1:2][1]); index = :subscript)

L"$\left( x_{:\left( 1, 2 \right)} \right)_{1}$"

Renders as $\left( x_{:\left( 1, 2 \right)} \right)_{1}$.

Thank you!

[karlwessel]

Btw: a similar problem exist when using a variable name that already contains a subscript:

latexify(:(x₁[2]); index = :subscript)
L"$x_1_{2}$"

And similar with superscripts:

latexify(:(x²^2))
L"$x^2^{2}$"

I didn't check if PR #316 also fixes those.

[gustaphe]

That's a separate issue. Not sure I think they are worth the effort, but if you open an issue for it, some kind soul might turn up with a PR :)