Need regex help with shortcode function

Shortcode is the term used by some content management systems to execute a program such as display a gallery on the frontend by converting some simple text entered in an editor in the backend. In the editor the admin types something like the following in the editor/textarea (saved in mysql): ------------------------------------------ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus mollis convallis justo, vitae pretium libero condimentum et. {[login to view URL] 1 2} Morbi nibh nibh, blandit sit amet sodales ullamcorper, ultricies vel nulla. {[login to view URL] 3 12} etc etc etc ------------------------------------------- In the first shortcode above [login to view URL] becomes $arg1, #1 is $arg2 and #2 is $arg3 With some help through stackoverflow I have it display the galleries but regular text is out of order and some there are some other problems. The task in hand is to finish off the regex expression so that it works correctly, in the right sequence and with any number of shortcodes. Here is a link to the stackoverflow post including a link to the demo. [login to view URL]