R: Set Options with Consistency Checks

check.options {grDevices} | R Documentation

## Set Options with Consistency Checks

### Description

Utility function for setting options with some consistency checks. The `attributes` of the new settings in `new` are checked for consistency with the model (often default) list in `name.opt`.

### Usage

    check.options(new, name.opt, reset = FALSE, assign.opt = FALSE,
                  envir = .GlobalEnv,
                  check.attributes = c("mode", "length"),
                  override.check = FALSE)

### Arguments

`new` | a named list
`name.opt` | character with the name of R object containing the default list.
`reset` | logical; if `TRUE`, reset the options from `name.opt`. If there is more than one R object with name `name.opt`, remove the first one in the `search()` path.
`assign.opt` | logical; if `TRUE`, assign the ...
`envir` | the `environment` used for `get` and `assign`.
`check.attributes` | character containing the attributes which `check.options` should check.
`override.check` | logical vector of length `length(new)` (or 1 which entails recycling). For those `new[i]` where `override.check[i] == TRUE`, the checks are overridden and the changes made anyway.

### Value

A list of components with the same names as the one called `name.opt`. The values of the components are changed from the `new` list, as long as these pass the checks (when these are not overridden according to `override.check`).

### Note

Option `"names"` is exempt from all the checks or warnings, as in the application it can be `NULL` or a variable-length character vector.

### Author(s)

Martin Maechler

### See Also

`ps.options` and `pdf.options`, which use `check.options`.

### Examples

    (L1 <- list(a = 1:3, b = pi, ch = "CH"))
    check.options(list(a = 0:2), name.opt = "L1")
    check.options(NULL, reset = TRUE, name.opt = "L1")

[Package grDevices version 4.0.5 Index]