First of all, a note: I intend all this post as encouragement to Emiliano, the author of Kalcoolus.
I can't post comments on kde-look (forgot my id, or maybe never registered), and I am not going to register just for this, but it's interesting to see how the same idea is recycled over and over and over.
This app seems to be a conflation of the following:
Writing frontends is good, because you don't need to write the hard part
A GUI calculator has to look like the real thing, in the name of usability
Well, the bad news is: writing frontends is fragile. What you want are libraries. And if GUIs had to look like the real thing, the UI to Skype would be a numpad, the UI to Amarok would look like an Ipod, and the UI to KWord would look different .
So, please, Emiliano, put a CLI in it. Pretty please? :-)