package options

Description Usage Arguments Path-like identifiers Author(s) References See Also Examples

Retrieves meta value from the respective environment for meta information inside an option container (see initializeOptionContainer).

1
2
3

getMetaValue(id, where = tryCatch(devtools::as.package(".")$package, error =
  function(cond) {     stop("Invalid default value for `where`") }),
  sub_id = character(), default = NULL, strict = c(0, 1, 2), ...)

`id`	Signature argument. Object containing path-like name/ID information.
`where`	Signature argument. Object containing information about the location of the option container that is to be used. Typically, this either corresponds to the name/ID of a package/package project or an instance of a custom class for which suitable methods in the context of managing options are defined (see other methods of this package that have signature arguments `id` or `where`).
`sub_id`	`character`. Optional ID for a sub layer. Useful for a hub-like option container structure.
`default`	`ANY`. Value to be returned if option does not exist. See `getOption` and `getNested`.
`strict`	`logical`. Controls what happens when `id` points to a non-existing meta object: 0: ignore and return `FALSE` to signal that the assignment process was not successful or `fail_value` depending on the value of `return_status` 1: ignore and with warning and return `FALSE` 2: ignore and with error
`...`	Further arguments to be passed to subsequent functions/methods.

Values for id are expected to be of structure a/b/c/.../z, i.e. path-like identifiers using a slash as separator. The identifier is transformed to a$b$c$...$z and then in turn to a valid get or assign expression (i.e. something similar to getOptionContainer(...)$a$b$c$...$z and getOptionContainer(...)$a$b$c$...$z <- value). Of course, "atomic" paths (e.g. only a) are also valid.

Janko Thyson janko.thyson@gmail.com

http://github.com/Rappster/optionr

getMetaValue-char-char-method, setMetaValue, existsMetaValue, rmMetaValue

## Not run: 

##------------------------------------------------------------------------------
## Default location of option container //
##------------------------------------------------------------------------------

## NOTE
## Obmitting `where` (and `id` in `initializeOptionContainer()`) in the all 
## calls will assign the overall option container to the package/project 
## name (if `hidden = TRUE` it is additionally prepended by a `.`)

initializeOptionContainer(overwrite = TRUE)
setMetaValue(id = "x_1", value = 10)
getMetaValue(id = "x_1")

##------------------------------------------------------------------------------
## Explicit location of option container //
##------------------------------------------------------------------------------

initializeOptionContainer(id = "test", overwrite = TRUE)
setMetaValue(id = "x_1", value = 10, where = "test")
getMetaValue(id = "x_1", where = "test")

##------------------------------------------------------------------------------
## Sub ID //
##------------------------------------------------------------------------------

initializeOptionContainer(sub_id = "a", overwrite = TRUE)
setMetaValue(id = "x_1", value = 10, sub_id = "a")
getMetaValue(id = "x_1", sub_id = "a")


## End(Not run)