Can I create multiple output files with touying, e.g. first and second half of a presentation?

[quachpas]

You probably want to read this post,

Can I configure my document (e.g. draft/release version, color theme) when creating a PDF without modifying the Typst file directly?

There absolutely is: the sys.inputs dictionary contains values that have been set from the command line, via the --input key=value syntax. To my knowledge, the web app currently doesn’t have a way to put values into that dictionary, so be aware of that. It’s often useful to have default values for these parameters, and check whether values are valid. Let’s say you want to assume --input theme=light and --input solutions=false, you could process the sys.inputs dictionary like this: let theme = …

It sounds possible to configure compilation to output parts of a document as long as they are probably indicated. Something like

#let part = int(sys.inputs.at("part", default: "0"))
// header
#if part == 0 or part == 1 {
  // part 1
}
#if part == 0 or part == 2 {
  // part 2
}

Then you would compile with

typst c test.typ --input=part=1

for part 1 for example