Add option to escape_string to avoid already escaped characters

[ronisbr]

Hi!

In PrettyTables.jl, sometimes it happens that a string has already some characters escaped, like \\cdot, but others not, like \n. However, I need to call escape_string every time to handle the other non-escaped characters (like \n), otherwise the output will break badly.

For example, if I try to pass to PrettyTables.jl a cell that has a LaTeX equation:

data = [ "\$ 10 \\cdot 20$" ]

then it will print:

$ 10 \\cdot 20 $"

because escape_string always treat \\ as two backslashes instead of one escaped backslash.

To solve this problem, I needed to copy the entire escape_string function and remove the line that transform \\ into \\\\. It would be nice, IMHO, if Julia's escape_string has a keyword option to assume \\ as an already escaped backslash.

If this is accepted, I can submit a PR.

[rohanxyzg]

Hi,
I would like to work on this issue.
Thanks

[ronisbr]

Hi @rohanxyzg !

I was about to submit a PR addressing this issue :)

I did not do this earlier because I was working on preparing PrettyTables.jl to be used in DataFrames.jl and I thought I would not need this anymore. I was wrong.

[ronisbr]

Done!