Simple error handler class can be use to intercept and log PHP execution errors. The class provides an error handler function that outputs a stack back-trace with the functions, arguments, file, and lines of where an error occurs, as well the values of super-global variables $_GET, $_POST, and $_FILES, and also the IP address of the current user accessing the site. When used with a MySQL class that triggers PHP errors on a MySQL error, you can use it as a means to debug broken MySQL queries.
A Simple Version Control System is an easy to install and easy to to use version/revision control system. It differs from most other version control systems in that it is designed to keep track of files in place. It does not allow any changes to be made to files; all changes require the users to change files externally with FTP or SSH access. It is very easy to set up and use. Users do not need to work with repository, branches, commit, and check-out files. All a user needs to do is upload the changes files and click Update, or if enabled, just wait for it to be updated automatically.
A practical lambda-calculator is a normal-order evaluator for the untyped lambda-calculus, extended with convenient commands and shortcuts to make programming in it more productive. Shortcuts are distinguished constants that represent terms. Commands define new shortcuts, activate tracing of all reductions, compare terms modulo alpha-conversion, print all defined shortcuts and evaluation flags, etc. Terms to evaluate and commands are entered at a read-eval-print-loop (REPL) "prompt" or "included" from a file by a special command. A Haskell branch is an embedding of the lambda calculator (as a domain-specific language) into Haskell. The calculator can be used interactively within Hugs or GHCi.