All steps to create a package with {fusen} from one Rmd file

• Create a new directory / new project with
  • RStudio template: File > New Project > New directory > Package using {fusen}
  • Choose the template teaching to start
    
  • Or command line: create_fusen("path/to/new/project", template = "teaching")
• Open the “dev/flat_teaching” Rmd to start setting up the package
• Run the content of the first development chunk with library(testthat) inside
• Modify and run the content of the chunk named description asking to describe your package and license it
  • For the first time, you can let the code as is, this is already the content for a working package
• Follow the "dev/flat_teaching.Rmd" template to write your documentation and build your functions and test your examples.
  • Chunk named function gets the code of a function
  • Chunk named example gets the code for examples of using the function. This will be used for function @examples and will be kept for the vignette
  • Chunk named tests gets the code for unit testing
  • Chunk named development gets the code for development purposes, usually only used once like {usethis} functions
• Run the dev-inflate chunk to inflate the flat template and transform it as an inflated package with functions, unit tests and the current Rmd template transformed as a vignette. And check.
• Build your {pkgdown} site to verify everything is at the right place

Create multiple "flat_xxx.Rmd" files with fusen::add_flat_template(template = "add") if needed

fill_description(
  pkg = dummypackage,
  fields = list(
    Title = "Build A Package From Rmarkdown file",
    Description = paste(
      "Use Rmarkdown First method to build your package.",
      "Start your package with documentation.",
      "Everything can be set from a Rmarkdown file in your project."
    ),
    `Authors@R` = c(
      person("John", "Doe", email = "john@email.me", role = c("aut", "cre"), comment = c(ORCID = "0000-0000-0000-0000")),
      person(given = "Company", role = "cph")
    )
  )
)

fusen::inflate(
  flat_file = "dev/flat_teaching.Rmd",
  vignette_name = "Exploration of my Data",
  open_vignette = TRUE,
  document = TRUE,
  check = TRUE
)

Create a new package from command line directly, using a pre-defined template

• Build a package from Rmd template in a temporary directory
  • This is for testing purposes

# Create a new project
dummypackage <- tempfile(pattern = "dummy")

# {fusen} steps
dev_file <- create_fusen(dummypackage, template = "teaching", open = FALSE)
# Description
fusen::fill_description(pkg = dummypackage, fields = list(Title = "Dummy Package"))

# From inside the package
usethis::with_project(dummypackage, {
  # Define License with use_*_license()
  usethis::use_mit_license("John Doe")

  # You may need to execute inflate() in the console directly
  fusen::inflate(
    pkg = dummypackage,
    flat_file = dev_file,
    vignette_name = "Get started"
  )
})

# Explore directory of the package
browseURL(dummypackage)

# Delete dummy package
unlink(dummypackage, recursive = TRUE)

Add a new “flat_template.Rmd” template in “dev/” directory

# Add an additional dev template
add_flat_template(template = "add", pkg = dummypackage)
# or directly
add_additional(pkg = dummypackage)

There can be development actions

These are only included in the flat template file, their content will not be part of the package anywhere else.

Name the following chunk with {r development-something, eval=FALSE}

```{r development-inflate, eval=FALSE}
# Run but keep eval=FALSE to avoid infinite loop

usethis::use_mit_license("John Doe")

# Execute in the console directly

fusen::inflate(flat_file = "dev/dev_history.Rmd")
```

Limitations

• One title / one chunk is for one function
• examples and tests chunks need to be placed after the associated function chunk
• You can add sub-functions in the function chunk to store them in the same R file, but they won’t have @examples. Only the first function of the chunk will be able to get examples.
• As for any Rmarkdown file, chunk names need to be unique. Thus, you better use examples-myfunction, examples-myotherfunction, …
• Do not forget to regularly clear your Workspace to avoid functions hidden by global environment