.add.extension: Associate a reader function with an extension.
Description
This function will associate an extension with a custom reader function.
Usage
.add.extension(extension, reader)
Value
No value is returned; this function is called for its side effects.
Arguments
extension
The extension of the new data file.
reader
The function to use when reading the data file. It should
accept three arguments: data.file, filename and
variable.name (in that order). The function should read the
contents of the file filename, and save it into the workspace
under the name variable.name. The data.file argument
is just a relative file name and can be ignored.
Warning
This interface should not be considered as stable and is likely to be
replaced by a different mechanism in a forthcoming version of this package.