Index of /web/packages/wayback/readme

	Name	Last modified	Size	Description
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	README.html	2020-09-21 11:00	11K

Rock Solid Package Installation for Legacy R Versions

Status

lines of R code: 299, lines of test code: 0

Version

0.2.3 ( 2020-08-19 20:27:40 )

Description

Make sure packages are available at runtime without any setup. Package installation, reproducibility and exchanging code can be frustrating especially if code is used on older R versions. Often it is hard to puzzle out which package versions are able to work together after some years have passed and packages evolved further and further. The ‘wayback’ package aims to make this process as painless and robust as possible by using ‘MRAN’s ’CRAN’ snapshots to build local package libraries from way back.

License

GPL-3
Peter Meissner [aut, cre], virtual7 [cph]

Citation

citation("wayback")

Meissner P (2020). wayback: Rock Solid Package Installation for Legacy R Versions. R package version 0.2.3.

BibTeX for citing

BibTeX(citation("wayback"))

@Manual{,
  title = {wayback: Rock Solid Package Installation for Legacy R Versions},
  author = {Peter Meissner},
  year = {2020},
  note = {R package version 0.2.3},
}

Installation

Stable version from CRAN:

install.packages("wayback")

Package Usage

library(wayback)

The main function of the package is wb_require(). Once {wayback} is installed this function allows to have required packages loaded from a library specified. In addition wb_require() will install packages that are not present but required.

The real core strength and purpose of the package is to install packages and dependencies from a specific point in time. This is provided by the date parameter allowing to go back in time - especially to a point in time where known to have consistent states of packages and dependencies for a given version of R.

suppressPackageStartupMessages(
  wb_require(
    pkg          = "glue", 
    date         = Sys.Date(),
    library_path = "./r_package_library"
  )
)

## loaded glue

info <- packageDescription("glue", lib.loc = "./r_package_library")

info$Packaged

## [1] "2020-05-13 14:58:42 UTC; jhester"

Package Use Cases and Scope

Package Maxims and Trade Offs

• given {wayback} is installed everything else should just work
• {wayback} will not change how your session works - e.g. normal install.packages() will work the same with and without {wayback}
• given that no date is provided the parameter date will default to 60 days after the currently used R version’s publication date
• {wayback} will not install anything if the required package is already found in the current path
• if however a explicit library path is provided - best practice - than {wayback} will assume that all packages and all dependencies
  • except base R packages - should come from this source
• dependencies are important: {wayback} will forcefully install dependencies
• providing a function that does package loading and installation is less ‘save’ than the standard usage of library() on the other hand this is common practice and {wayback} scratches this itch in hope to provide a solid, effective and robust solution to the problem
• behavior should - by default - stem from function parameters only
• to minimize re-writing function parameters over and over again all function parameters can be set via options

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