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-- L -- load_config()

Load configuration

Description

Load a user defined configuration from file. By default (i.e. when as_is = FALSE), load_config() requires inputs to be given as uniquely-named lists. It first parses the configuration file looking for a 'default' entry. With no additional arguments this will be returned as a list to the user. If the user specifies an additional list to consider (via the config argument) then this list is layered on top (using utils::modifyList()).

Usage

load_config(filename, config, ..., as_is = FALSE, default = "default")

Arguments

filename	Configuration file to read from.
config	Name of entry in configuration file to layer on top of 'default'. Not used if as_is = TRUE.
...	Not currently used.
as_is	Should the configuration file be read in as is, without layering on top of the default config? Defaults to FALSE.
default	The default configuration to use.

Details

Configuration files can be specified using a reduced subset of base R. Currently this is restricted to the following operators and functions:

• <-, =, +, -, *, :,

• as.Date (for character inputs),

• array, matrix,

• list, data.frame,

• c,

• length,

• seq (for numeric and date inputs),

• sequence (for numeric inputs),

• seq_len, seq_along,

• Sys.Date and Sys.time.

We also enable a convenience function, cc, which automatically quotes input to save typing.

Value

If as_is = FALSE (default) a list contain entries corresponding to the chosen config. If as_is = TRUE, a list of all entries in the evaluated configuration file.

Examples

# load the example configuration
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
#> )

# default configuration
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 ...

# debug configuration
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

# forecast configuration
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 ...