Targets + Bookdown

I originally used the approach of https://github.com/robitalec/targets-parameterized-bookdown but with that approach equations will not work. This renders the chapters to markdown and equations (unless very simple) won't work. But a fairly simple tweak will allow it to work. Basically use knitr::knit() instead of rmarkdown::render() to create the rendered R Markdown files.

update This doesn't work as it breaks all the figure legends from {bookdown}. It replaces images with <img> html tags and that loses all the info that {bookdown} needs to make legends. I tried rmarkdown::render() with some {bookdown} output formats but couldn't figure out a what to get both the figure legends and refs plus the equations.

This gives an html fragment that can be included but lose all the heading (chapter, section) info.

rmarkdown::render("chap2.Rmd", output_format = bookdown::html_fragment2(self_contained = FALSE))

This is an attempt to use {targets} with {bookdown} to track the status of chapter and not re-render chapters each time the book needs to be rebuilt. At the book level, the dependencies are super simple, just checks if the chapter Rmd has changed. But for a specific chapter, you can have a separate {targets} pipeline that might be much more complex. {targets} projects is probably a better way to go in that situation.

Why did I do this? I have many big bookdown projects and re-building is always a bit of torture. The bookdown caching feature is quite buggy and crashes my R session all the time. Hopefully this works better.

To run the book

• Install the {targets}, {tarchetypes} and {bookdown} packages
• Type tar_make() at the command line.
• Look in the _book folder for the index.html file and open that.

To add chapters

• The chapters are in the chapters folder. Add an Rmd there.
• Open the _targets.R file and add something like target_factory(chap2) but replace chap2 with your file name.
• chapters/chap3 shows and example where the chapter uses targets markdown to create a chapter specific pipeline. To run, set chapters/chap3 as the working directory, open chap3.Rmd and knit. Then

Explanations

• _targets.R is setting up the targets objects so {targets} can keep track of when objects need to be updated (because a dependency changed)
• R/chapterfactory.R is a file I wrote to create the chapter dependencies and objects. Basically it just renders a chapter Rmd and put the rendered version (md) into the folder rendered-chapters folder.
• Use tar_visnetworks() to visualize the network and status.

Re-use statement

Please re-use however you want. No attribution needed.