Solutions to the exercises from The Little Book of Semaphores by Allen Downey.
Also includes a hacked up version of Downey's simulator Sync, with the following changes:
- The GUI is gone: it's intended to be run either on the command line or controlled by another program.
- Function and class definitions are supported in user code. Definitions are evaluated atomically; function calls are atomic. The idea is that these can be used to test correctness, for use in tests.
- By default, threads don't loop round back to the top once they're finished. You can control this with the --loop option.
- You can also fail immediately on deadlock, control the delay, or set a
maximum number of steps with command-line options; run
sync --helpfor a list.
The idea (illustrated by some of the tests) is to run Sync headlessly under the control of Hypothesis for program verification.