jarodmeng/lookup

Lookup R full function definitions, including compiled code, S3 and S4 methods.

lookup

Lookup R function definitions, including compiled code, S3 and S4 methods.

[](https://codecov.io/github/jimh ester/lookup?branch=master)

Installation

# install.packages("devtools")
devtools::install_github("jimhester/lookup")

Example

Normal Functions (with compiled code)

S3 generics and methods

S4 generics and methods

In RStudio IDE

Setup

lookup makes heavy use of the GitHub API, which has a rate limit of 60 requests per hour when unauthenticated. You can create a Personal access token with no scope, which will increase your limit to 5000 requests per hour.

Once you have generated a token, add it to your ~/.Renviron file or shell startup file and it will be automatically used for further requests.

GITHUB_PAT=7d8d0436835d1baXYZ1234

gh::gh("/rate_limit") can be used to query your current usage and limits.

Default printing

lookup can be used as a complete replacement for function printing by attaching the package. To make this the default simply add this to your .Rprofile.

if (interactive()) {
  library(lookup)
}

How this works

If a base R function is printed that calls compiled code the code is lookup up using the R git mirror. If a CRAN package has compiled code it is looked up on the CRAN git mirror. If a package is installed with devtools::install_github() or devtools::install() the remote or local repository location is searched for the code.

This has been tested to work with .Internal, .External, .C, .Call and Rcpp calls.

Issues

This package uses a number of heuristics to find function definitions. This means it can fail in some cases, if you find a function that is not lookup up properly, please open an issue.

Thanks

• R Core and Community For promoting open source software to make this possible.
• Winston Chang For running the Git mirror of the R Source.
• Gábor Csárdi For the gh package, the CRAN git mirror and inspiration and code for handling pagination and busy updating.
• Jenny Bryan For codifying the process of accessing the R source, which was my main inspiration and motivation for starting this package.