Feature Request: Service / stdin/stdout mode

So there is this crazy person who matched highlight with grep: https://github.com/misaki-web/grepp for quite the interesting result. It opened an application for highlight I had not considered before and could apply to other potential output.

The main problem is it requires running a separate instance of highlight for every line. This is two fold: 1) The syntax may change 2) Comments or seemingly multi-line text on one line would cause additional lines to inherit this even if they are different files.

This is further exacerbated on platforms like windows where there are significant startup costs for a process.

Now this use case may not be an overly important one but a STDIN/OUT server mode could be useful in other situations. The idea being a controlling process could start highlight and then change syntax / feed files through STDIN and get outputs back through stdout. This allows a long running highlight instance able to handle line/file changes faster.

This could be done using something like EOF or a null byte as a delimiter. The syntax file thing would likely need a custom start sequence to differentiate setting the style from normal stdin.