Regexp building blocks test

This project is a proof-of-concept for using visual blocks (like in Scratch or Snap!) to build regular expression patterns. I believe that something like this could be useful for teaching RegExp patterns because it allows new users to "explore" regular expressions without dealing with keywords and syntax errors, just like Scratch and Snap! do for general programming.

To try the blocks for yourself, click "see code" and go to the "variables" section to use the gray blocks.

Note: this project is a proof of concept. It's not perfect; one limitation is that string input to blocks is not "sanitized" to escape special characters such as *, +, . and (