Helper used to merge defaults with user arguments, remove
forbidden argument names, and optionally warn if forbidden arguments
were supplied.
Usage
mergeArgs(defaults, user, forbidden = NULL, warn = TRUE)
Arguments
- defaults
named list of default arguments.
- user
named list of user-supplied arguments, or NULL.
- forbidden
character vector of argument names that are not allowed.
- warn
logical; whether to issue a warning if forbidden arguments are removed.
Value
a named list of merged arguments.
Details
User values override defaults of the same name. Unlike
modifyList(), elements with the value NULL are
preserved (so that an explicit NULL can be passed on as an
argument value instead of silently deleting the entry).
Examples
mergeArgs(list(col = "black", lty = 1), list(col = "red"))
#> $col
#> [1] "red"
#>
#> $lty
#> [1] 1
#>
# explicit NULL survives the merge
mergeArgs(list(col = "black"), list(col = NULL))
#> $col
#> NULL
#>
