An existing interactive graphical application has two parts: A complex VLSI data model managed by an efficient C++ class library, and a user interface (command-line and GUI) implemented in Tcl.

The challenge: Implement a new non-trivial module, including parsers for new file formats and management and validation of new data types. Do it quickly and reliably, producing tested and maintainable code which integrates smoothly with the existing system. Release it to users, including external users, transparently, without requiring additional installations on their part.

The solution: Perl, of course!

I'll outline the structure of the original system, why Perl was chosen for the extension, implementation and release techniques used, drawbacks and challenges, etc.