I feel someone should point out that "set" in this usage is a csh thing. The slides and the referenced comment use Bourne-type shells, where "set" is a builtin mostly used to set shell options: http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_...

In csh, where using "set" like this would work, you can actually put spaces around the = (go figure).

I'm not aware of () being used for quoting words in any variant of sh or csh.