use_standalone.md
In usethis: Automate Package and Project Setup

can offer choices

Code
  standalone_choose("tidyverse/forcats", ref = "v1.0.0")
Condition
  Error:
  ! No standalone files found in tidyverse/forcats.
Code
  standalone_choose("r-lib/rlang", ref = "4670cb233ecc8d11")
Condition
  Error:
  ! `file` is absent, but must be supplied.
  i Possible options are cli, downstream-deps, lazyeval, lifecycle, linked-version, obj-type, purrr, rlang, s3-register, sizes, types-check, vctrs, or zeallot.

header provides useful summary

Code
  standalone_header("r-lib/usethis", "R/standalone-test.R")
Output
  [1] "# Standalone file: do not edit by hand"                                    
  [2] "# Source: <https://github.com/r-lib/usethis/blob/main/R/standalone-test.R>"
  [3] "# ----------------------------------------------------------------------"  
  [4] "#"

can extract imports

Code
  extract_imports("# imports: rlang (== 1.0.0)")
Condition
  Error in `extract_imports()`:
  ! Version specification must use `>=`.
Code
  extract_imports("# imports: rlang (>= 1.0.0), purrr")
Condition
  Error in `extract_imports()`:
  ! Version field can't contain comma.
  i Do you need to wrap in a list?
Code
  extract_imports("# imports: foo (>=0.0.0)")
Condition
  Error in `extract_imports()`:
  ! Can't parse version `foo (>=0.0.0)` in `imports:` field.
  i Example of expected version format: `rlang (>= 1.0.0)`.

errors on malformed dependencies

Code
  standalone_dependencies(c(), "test.R")
Condition
  Error:
  ! Can't find yaml metadata in 'test.R'.
Code
  standalone_dependencies(c("# ---", "# dependencies: 1", "# ---"), "test.R")
Condition
  Error:
  ! Invalid dependencies specification in 'test.R'.