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desc

Parse DESCRIPTION files

Parse, manipulate and reformat DESCRIPTION files. The package provides two APIs, one is object oriented, the other one is procedural and manipulates the files in place.

• Installation
• The object oriented API
  • Introduction
  • Loading or creating new DESCRIPTION files
  • Normalizing DESCRIPTION files
  • Querying, changing and removing fields
  • Dependencies
  • Collate fields
  • Authors
• The procedural API
• License

Installation

# Install the released version from CRAN
install.packages("desc")

# Or the development version from GitHub:
# install.packages("pak")
pak::pak("r-lib/desc")

The object oriented API

library(desc)

Introduction

The object oriented API uses R6 classes.

Loading or creating new DESCRIPTION files

A new description object can be created by reading a DESCRIPTION file form the disk. By default the DESCRIPTION file in the current directory is read:

desc <- description$new()

desc

#> Package: desc
#> Title: Manipulate DESCRIPTION Files
#> Version: 1.0.0
#> Author: Gábor Csárdi
#> Maintainer: Gábor Csárdi <csardi.gabor@gmail.com>
#> Description: Tools to read, write, create, and manipulate DESCRIPTION
#>     files.  It is intented for packages that create or manipulate other
#>     packages.
#> License: MIT + file LICENSE
#> URL: https://github.com/r-lib/desc
#> BugReports: https://github.com/r-lib/desc/issues
#> Imports:
#>     R6
#> Suggests:
#>     newpackage,
#>     testthat,
#>     whoami
#> Encoding: UTF-8
#> LazyData: true
#> RoxygenNote: 5.0.0

A new object can also be created from scratch:

desc2 <- description$new("!new")
desc2

#> Package: {{ Package }}
#> Title: {{ Title }}
#> Version: 1.0.0
#> Authors@R (parsed):
#>     * Jo Doe <jodoe@dom.ain> [aut, cre]
#> Maintainer: {{ Maintainer }}
#> Description: {{ Description }}
#> License: {{ License }}
#> URL: {{ URL }}
#> BugReports: {{ BugReports }}
#> Encoding: UTF-8

Normalizing DESCRIPTION files

Most DESCRIPTION fields may be formatted in multiple equivalent ways. desc does not reformat fields, unless they are updated or reformatting is explicitly requested via a call to the normalize() method or using the normalize argument of the write() method.

Querying, changing and removing fields

get() and set() queries or updates a field:

desc$set("Package", "foo")
desc$get("Package")

#> Package 
#>   "foo"

They work with multiple fields as well:

desc$set(Package = "bar", Title = "Bar Package")
desc$get(c("Package", "Title"))

#>       Package         Title 
#>         "bar" "Bar Package"

Dependencies

Package dependencies can be set and updated via an easier API:

desc$get_deps()

#>       type    package version
#> 1 Suggests   testthat       *
#> 2 Suggests     whoami       *
#> 3 Suggests newpackage       *
#> 4  Imports         R6       *

desc$set_dep("mvtnorm")
desc$set_dep("Rcpp", "LinkingTo")
desc$get_deps()

#>        type    package version
#> 1  Suggests   testthat       *
#> 2  Suggests     whoami       *
#> 3  Suggests newpackage       *
#> 4   Imports    mvtnorm       *
#> 5   Imports         R6       *
#> 6 LinkingTo       Rcpp       *

desc

#> Package: bar
#> Title: Bar Package
#> Version: 1.0.0
#> Author: Gábor Csárdi
#> Maintainer: Gábor Csárdi <csardi.gabor@gmail.com>
#> Description: Tools to read, write, create, and manipulate DESCRIPTION
#>     files.  It is intented for packages that create or manipulate other
#>     packages.
#> License: MIT + file LICENSE
#> URL: https://github.com/r-lib/desc
#> BugReports: https://github.com/r-lib/desc/issues
#> Imports:
#>     mvtnorm,
#>     R6
#> Suggests:
#>     newpackage,
#>     testthat,
#>     whoami
#> LinkingTo:
#>     Rcpp
#> Encoding: UTF-8
#> LazyData: true
#> RoxygenNote: 5.0.0

Collate fields

Collate fields can be queried and set using simple character vectors of file names:

desc$set_collate(list.files("../R"))

#> Warning in idesc_set_collate(self, private, files, match.arg(which)): No files
#> in 'Collate' field

desc$get_collate()

#> character(0)

Authors

Authors information, when specified via the Authors@R field, also has a simplified API:

desc <- description$new("tools/pkg2")
desc$get_authors()

#> [1] "Hadley Wickham <h.wickham@gmail.com> [aut, cre, cph]"
#> [2] "Peter Danenberg <pcd@roxygen.org> [aut, cph]"        
#> [3] "Manuel Eugster [aut, cph]"                           
#> [4] "RStudio [cph]"

desc$add_author("Bugs", "Bunny", email = "bb@acme.com")
desc$add_me()
desc$add_author_gh("jeroen")
desc$get_authors()

#> [1] "Hadley Wickham <h.wickham@gmail.com> [aut, cre, cph]"
#> [2] "Peter Danenberg <pcd@roxygen.org> [aut, cph]"        
#> [3] "Manuel Eugster [aut, cph]"                           
#> [4] "RStudio [cph]"                                       
#> [5] "Bugs Bunny <bb@acme.com>"                            
#> [6] "First Last <first.last@dom.com> [ctb]"               
#> [7] "Jeroen Ooms <jeroen@berkeley.edu> [ctb]"

If the Author field is specified, it can be changed to a Authors@R field using coerce_authors_at_r(), incorporating the Maintainer information if necessary:

desc <- description$new("!new")
desc$del("Authors@R")
desc$del("Maintainer")
desc$set(Author = "Gábor Csárdi <csardi.gabor@gmail.com>")
desc$get_authors()

#> Error in ensure_authors_at_r(self): No 'Authors@R' field!
#> You can create one with $add_author.
#> You can also use $coerce_authors_at_r() to change Author fields

desc$coerce_authors_at_r()
desc$get_authors()

#> [1] "Gábor Csárdi <csardi.gabor@gmail.com> [aut]"

The procedural API

The procedural API is simpler to use for one-off DESCRIPTION manipulation, since it does not require dealing with description objects. Each object oriented method has a procedural counterpart that works on a file, and potentially writes its result back to the same file.

For example, adding a new dependency to DESCRIPTION in the current working directory can be done with

desc_set_dep("newpackage", "Suggests")

#> Package: desc
#> Title: Manipulate DESCRIPTION Files
#> Version: 1.4.2.9000
#> Authors@R (parsed):
#>     * Gábor Csárdi <csardi.gabor@gmail.com> [aut, cre]
#>     * Kirill Müller [aut]
#>     * Jim Hester <james.f.hester@gmail.com> [aut]
#>     * Maëlle Salmon [ctb] (<https://orcid.org/0000-0002-2815-0399>)
#>     * Posit Software, PBC [cph, fnd]
#> Maintainer: Gábor Csárdi <csardi.gabor@gmail.com>
#> Description: Tools to read, write, create, and manipulate DESCRIPTION
#>     files.  It is intended for packages that create or manipulate other
#>     packages.
#> License: MIT + file LICENSE
#> URL: https://desc.r-lib.org/, https://github.com/r-lib/desc
#> BugReports: https://github.com/r-lib/desc/issues
#> Depends:
#>     R (>= 3.4)
#> Imports:
#>     cli,
#>     R6,
#>     utils
#> Suggests:
#>     callr,
#>     covr,
#>     gh,
#>     newpackage,
#>     spelling,
#>     testthat,
#>     whoami,
#>     withr
#> Config/Needs/website: tidyverse/tidytemplate
#> Config/testthat/edition: 3
#> Encoding: UTF-8
#> Language: en-US
#> Roxygen: list(r6 = FALSE, load = "installed", markdown = TRUE)
#> RoxygenNote: 7.2.3
#> Collate:
#>     'assertions.R'
#>     'authors-at-r.R'
#>     'built.R'
#>     'classes.R'
#>     'collate.R'
#>     'constants.R'
#>     'deps.R'
#>     'desc-package.R'
#>     'description.R'
#>     'encoding.R'
#>     'find-package-root.R'
#>     'latex.R'
#>     'non-oo-api.R'
#>     'package-archives.R'
#>     'read.R'
#>     'remotes.R'
#>     'str.R'
#>     'syntax_checks.R'
#>     'urls.R'
#>     'utils.R'
#>     'validate.R'
#>     'version.R'

This added newpackage to the Suggests field:

desc_get("Suggests")

#>                                                                                                  Suggests 
#> "\n    callr,\n    covr,\n    gh,\n    newpackage,\n    spelling,\n    testthat,\n    whoami,\n    withr"

So the full list of dependencies are now

desc_get_deps()

#>        type    package version
#> 1   Depends          R  >= 3.4
#> 2   Imports        cli       *
#> 3   Imports         R6       *
#> 4   Imports      utils       *
#> 5  Suggests      callr       *
#> 6  Suggests       covr       *
#> 7  Suggests         gh       *
#> 8  Suggests newpackage       *
#> 9  Suggests   spelling       *
#> 10 Suggests   testthat       *
#> 11 Suggests     whoami       *
#> 12 Suggests      withr       *

Code of Conduct

Please note that the desc project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.