I had an issue at work where some database writes were throwing errors within a thread, and the error was being silently eaten when the thread died.
Bayes’ theorem is a way of determining the likelihood of an event A given that another event B has occurred. It’s a way of making an educated guess without much information to go on.
rein is a gem for adding database constraints in rails migrations. It’s always been possible to set these up using execute calls in the migration, but rein makes it look rails-y.
rubycheck is a library implementing similar functionality to the quickcheck library in haskell. Using rubycheck, you can write assertions that a method works for all given inputs meeting a given criteria. Of course, the implementation is to just try a bunch of options and see whether they all meet the desired outcome. Using rubycheck gives you the power to verify your code works for a wider variety of cases than you might normally put into a unit test (or at least lets you hide the random input generator within a gem).
An L-System is a set of rules for rewriting a string. This generally creates recursive patterns in the generated strings, and in all the examples I’ve worked on, these are used to build turle graphics programs.