Configuration files for R projects

ronfig aims to enable intuitive configuration of R projects via a single function, load_config(). It’s raison d’être is to handle the situation where you have multiple, somewhat overlapping, parameter configurations that you want to quickly switch between whilst avoiding, potentially error-inducing, copy and paste.

To keep things simple, rather than introducing another language for our configuration file, we restrict ourselves to a subset of base R. Currently we allow the following set of functions/operators:

This use of a reduced subset of R is primarily to ensure that loading a configuration file has no side-effects on a users environment and performs limited computation. Under the hood, load_config() is little more than careful wrapping of base::sys.source() and utils::modifyList() with care taken as to where evaluation takes place.

Example

Configuration file

Configuration files look similar to the following example file that we bundle in the package:

file <- system.file("config.R", package = "ronfig")
cat(readChar(file, file.info(file)$size))

# This is our default configuration which must be a named list
# All other changes are layered on top of this.
default <- list(
    date = as.Date("2025-09-02"),
    N = 1000,
    alpha = 0.3,
    gamma = 0.2,
    beta = 0.7,
    max_delay = 30,
    years = 2006:2025
)

# You may need to debug some results and wish to set one parameter to 0 and only
# look at a reduced number of years, e.g.
debug <- list(
    years = 2024:2025,
    alpha = 0
)

# Or you may wish to consider an extended range of years
forecast <- list(
    years = 2006:2030
)

Loading

We can easily load any of the example configurations in to a list in our local environment:

library(ronfig)
str(load_config(file))

#> List of 7
#>  $ date     : Date[1:1], format: "2025-09-02"
#>  $ N        : num 1000
#>  $ alpha    : num 0.3
#>  $ gamma    : num 0.2
#>  $ beta     : num 0.7
#>  $ max_delay: num 30
#>  $ years    : int [1:20] 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 ...

str(load_config(file, "debug"))

#> List of 7
#>  $ date     : Date[1:1], format: "2025-09-02"
#>  $ N        : num 1000
#>  $ alpha    : num 0
#>  $ gamma    : num 0.2
#>  $ beta     : num 0.7
#>  $ max_delay: num 30
#>  $ years    : int [1:2] 2024 2025

str(load_config(file, "forecast"))

#> List of 7
#>  $ date     : Date[1:1], format: "2025-09-02"
#>  $ N        : num 1000
#>  $ alpha    : num 0.3
#>  $ gamma    : num 0.2
#>  $ beta     : num 0.7
#>  $ max_delay: num 30
#>  $ years    : int [1:25] 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 ...

Related work