One of [aspect]'s favourite things about Tcl, that he cites to anyone who will listen, is that it '''Plays Well With Others'''.  This shouldn't be a surprise given [JO]'s original vision for the system as a "Glue language", but how well Tcl succeeds in this respect is really quite a marvel.

[Inventory of IPC methods] lists some of the ways.  [Unicode] support is still impressive.  On Windows there are things like [CAWT] and [TWAPI].  [Expect] is the granddaddy of playing well with others, and still incredibly widely used.  Accessing native libraries with [critcl] or [tcc4tcl] is almost too easy.

Because [everything is a string], conversing with another process is trivial:  do as much parsing as you need and no more.  Contrast the approach in [Lisp] or even [Python] or [Javascript] where external data needs to be brought into the native world-view ([s-expressions], or [JSON]) to conveniently consume.

For consideration:  in how many languages could you consider the below a relatively simple program, requiring only hundreds of lines of code for each feature?

   * presents a simple GUI with some desktop interaction
   * manages a [Serial port]
   * listens for [syslog] messages
   * manages a couple of external processes

And then what if you needed to add:

   * wraps a native library
   * provides a simple scripting interface to the user
   * builds and runs as a portable app on multiple platforms