Purpose: describe the various methods available within Tcl for code reuse. Cut/copy and paste: user maintains a series of text files containing tcl code and then just copies the text when needed. source: tcl has a command called '''source''' which reads a file, treating the contents just as if they were a part of the original file. load: tcl has a command called '''load''' which is used to attach a dynamically loadable object extension to the current library. packages: See Will Duquette's "Guide to Success with Namespaces and Packages" at http://www.cogent.net/~duquette/tcl/namespaces.html . unknown: tcl has a command called '''unknown''' which is invoked whenever the tcl interpreter is unable to determine a particular command. unknown does some processing and can provide dynamic sourcing of functions. Details go here. See [Radical Language Modification] for examples how to deal with the unknown. exec: '''exec''' is a tcl command used to invoke a stand alone command. This command can be written in any language supported by the system. [Cameron Laird] wrote a nice explanation of some of the common questions about exec on comp.lang.tcl a while ago - see http://x8.dejanews.com/getdoc.xp?AN=389920667 for the article. pipe: tcl supports, in the '''open''' command, the ability to open an input and/or output pipeline to another process, which is started in a manner similar to the exec command. ---- I hope people stopping by this page will update the above descriptions to fill in a lot of the details (where does pkgIndex, tclIndex come in - what other options are available, etc.).