write_bib {knitr} | R Documentation

## Generate BibTeX bibliography databases for R packages

### Description

This function uses `citation` and `toBibtex` to create bib entries for R packages and write them in a file. Only the auto-generated citations are included for a package. This function can facilitate the auto-generation of bibliography databases for R packages, and it is easy to regenerate all the citations after updating R packages.

### Usage

    write_bib(x = .packages(), file = "", tweak = TRUE, width = NULL,
        prefix = getOption("knitr.bib.prefix", "R-"))

### Arguments

`x` | Package names. Packages which are not installed are ignored.
`file` | The (‘.bib’) file to write. By default, or if `NULL`, output is written to the R console.
`tweak` | Whether to fix some known problems in the citations, especially non-standard format of author names.
`width` | Width of lines in bibliography entries. If `NULL`, lines will not be wrapped.
`prefix` | Prefix string for keys in BibTeX entries; by default, it is R- unless `option('knitr.bib.prefix')` has been set to another string.

### Details

The citation is forced to be generated from the ‘DESCRIPTION’ file of the package (`citation(auto = TRUE)`). The keyword R-pkgname is used for the bib item, where pkgname is the name of the package. All references specified in the ‘CITATION’ file of the package are ignored. The main purpose of this function is to automate the generation of the package citation information because it often changes (e.g. author, year, package version, ...). By comparison, paper/book citations don't change too often, so it is not a lot of work even if you just cut and paste such bibliography entries from `toBibtex(citation())`.

### Value

A list containing the citations. Citations are also written to the `file` as a side effect.

### Note

Some packages on CRAN do not have standard bib entries, which was once reported by Michael Friendly at https://stat.ethz.ch/pipermail/r-devel/2010-November/058977.html. I find this a real pain, and there are no easy solutions except contacting package authors to modify their DESCRIPTION files. Anyway, the argument `tweak` has provided ugly hacks to deal with packages which are known to be non-standard in terms of the format of citations; `tweak = TRUE` is by no means intended to hide or modify the original citation information. It is just due to the loose requirements on package authors for the DESCRIPTION file. On one hand, I apologize if it really mangles the information about certain packages; on the other, I strongly recommend package authors to consider the Authors@R field (see the manual Writing R Extensions) to make it easier for other people to cite R packages. See `knitr:::.tweak.bib` for details of tweaks. Also note this is subject to future changes since R packages are being updated. If you want to contribute more tweaks, please edit the file ‘inst/misc/tweak_bib.csv’ in the source package.

### Author(s)

Yihui Xie and Michael Friendly

### Examples

    write_bib(c("RGtk2", "gWidgets"), file = "R-GUI-pkgs.bib")
    write_bib(c("animation", "rgl", "knitr", "ggplot2"))
    write_bib(c("base", "parallel", "MASS"))  # base and parallel are identical
    write_bib("cluster", prefix = "")  # a empty prefix
    write_bib("digest", prefix = "R-pkg-")  # a new prefix
    write_bib("digest", tweak = FALSE)  # original version

    # what tweak=TRUE does
    str(knitr:::.tweak.bib)

[Package knitr version 1.22 Index]