07-knitr

Writing a report

1. Start an R session in this directory (07-knitr)

   • RStudio users, open the *.Rproj file in this directory

2. Build the project:

   remake::make()

3. Fetch the ragout:

   remake::fetch("ragout")

4. Create a new file final.Rmd in this directory, with the following contents:

   ---
   title: "Final cooking report"
   author: "<Your name>"
   output: rmarkdown::html_document
   ---
   
   ```{r init, echo = FALSE, message = FALSE}
   if (!isNamespaceLoaded("remake")) remake::create_bindings()
   ```
   
   Look at the ragout I made today:
   
   ```{r}
   ragout
   ```
   
   I combined fried meat and vegetables:
   
   ```{r}
   fried_meat
   cooked_potatoes
   peeled_carrots
   ```
   
   Some of the components were more difficult to prepare than others:
   
   ```{r}
   plot(
     factor(c("Fried meat", "Cooked potatoes", "Peeled carrots")),
     sapply(
       list(fried_meat, cooked_potatoes, peeled_carrots),
       function(x) length(format(x))
     )
   )
   ```
   

5. Render the document using rmarkdown::render("final.Rmd"), preferably in a fresh R session.

   • RStudio users can hit Ctrl+Shift+K when final.Rmd is open

6. View the resulting final.html in your browser.

7. Create a file R/knit.R with the following contents:

   knit_with_deps <- function(target_name, source_name, ..., envir = parent.frame()) {
     dep_names <- as.character(unlist(substitute(list(...))[-1]))
     deps <- list(...)
     names(deps) <- dep_names
     deps <- deps[unique(names(deps))]
   
     dep_env <- as.environment(deps)
     parent.env(dep_env) <- envir
   
     rmarkdown::render(
       input = source_name,
       output_format = "all", envir = dep_env
     )
   }

8. Add the following rule to your targets in remake.yml:

     final.html:
       command: knit_with_deps(target_name, "final.Rmd", ragout, peeled_carrots, cooked_potatoes, fried_meat)
   

9. Make sure the final.html target is part of the main target!

   targets:
     all:
       depends:
       - ragout
       - final.html
   

10. Build the project.

11. View the resulting final.html in your browser, again.