This proc is defined in tcl's package.tcl library file.
This is a utility procedure use by pkgIndex.tcl files. It is invoked as part of a "package ifneeded" script. It calls "package provide" to indicate that a package is available, then sets entries in the auto_index array so that the package's files will be auto-loaded when the commands are used.
Arguments:
- dir
- Directory containing all the files for this package.
- pkg
- Name of the package (no version number).
- version
- Version number for the package, such as 2.1.3.
- files
- List of files that constitute the package. Each element is a sub-list with three elements. The first is the name of a file relative to $dir, the second is "load" or "source", indicating whether the file is a loadable binary or a script to source, and the third is a list of commands defined by this file.