Ward offers a carefully typed reference implementation along with scripted navigation scenarios as a text file ready to Exercise the Link Logic you might implement in your favorite technology. See matrix
reference, 350 lines
test script, 55 lines
See also Scripter.
interpreter

Interpreter
Evaluate:
```smalltalk interpreter nextLine ```
For each evaluation, a line is added to the log. The line is in the Live section of the Transcript.
See also Canon TDD