Included as part of futile is an options subsystem that facilitates the
management of options for a particular application. The options.manager
function produces a scoped options set within the environment, to protect
against collisions with other libraries or applications. The options subsystem
also provides default settings that can be restored by calling reset.options.
Usage
OptionsManager(option.name, defaults = list())
## Default S3 method:
resetOptions(option.name, ...)
## S3 method for class 'character'
resetOptions(option.name, ...)
## Default S3 method:
updateOptions(option.name, ...)
## S3 method for class 'character'
updateOptions(option.name, key, value, ...)
options.manager(option.name, defaults = NULL)
reset.options(option.name, ...)
Arguments
option.name
The namespace of the options set
defaults
A list of default values to use for the new options manager
key
A vector of keys in the options that need to be updated
value
A vector of values that correspond to the keys above
...
Option values to set after resetting
Details
Using the options subsystem is simple. The first step is to create a specific
options manager for a given namespace by using the 'OptionsManager' function.
It is possible to specify some default values by passing a list to the default
argument. This function returns a specialized function for managing options in
the given namespace.
With the new function, options can be set and accessed in an isolated
namespace. The options can also be reset using 'resetOptions' to the default
values.
Note that if multiple values are accessed, to support lists and other complex
data structures, the output is a list. If a vector is preferred, pass
simplify=TRUE as an argument to the user-defined options management function.
Another arugment available in the resulting function is 'update', which allows
specific values to be updated dynamically rather than via named key=value
pairs. This is useful in certain situations but can be safely ignored for
most situations.
To reset options back to default settings, use the 'reset.options' function.
In certain cases, stored options may need to be set programattically, i.e.
their name is constructed dynamically. When this occurs, use update.options to
set the values.
NOTE: The functions 'options.manager' and 'reset.options' are deprecated but
still extant to maintain backwards compatibility. All futile libraries are
renamed to avoid naming collisions with S3 generics. Furthermore, any futile
function that returns a function will be PascalCased, whereas all others will
be camelCased. The dot notation is reserved strictly for S3 generics.
Value
The 'OptionsManager' function produces a custom function to manage options
for the specified namespace. Use this function to access and set options in
your code.