This is a PHP class that attempts to validate a given e-mail address at four levels: matching the address against a RFC compliant regular expression; checking whitelists and blacklists of domains with typing mistakes, disposable email addresses, and temporary and fake domains; verifying the existence of the destination SMTP server by verifying the respective DNS MX record; and connecting to that server to see if the given address is accepted as a valid recipient. The class also features a debugging output option that lets you see the remote SMTP server connection and data exchange dialog to see the real cause why an apparently valid address may not be accepting messages.
TinyScheme is a lightweight Scheme interpreter that implements as large a subset of R5RS as possible without getting very large and complicated. It is meant to be used as an embedded scripting interpreter for other programs. As such, it does not offer IDEs or extensive toolkits although it does sport a small top-level loop, included conditionally. A lot of functionality in TinyScheme is included conditionally, and it allows multiple interpreter states to coexist in the same program without any interference between them. Foreign functions in C can also be added and values can be defined in the Scheme environment.