In http://git.gnome.org/cgit/gcalctool/commit/?id=d16a5b07b64239213c9ac985a31cb9c89db6b507 I added a new "swearword button" to the financial mode, that implements a somewhat rough version of this. There's still work to be done, but I'm hoping for some feedback before I spend too much time with it.


The currency rates are downloaded from the European central bank, just like in Qalculate. The list of available currencies is therefore a bit eurocentric, however, it's a freely available source, and they actually like 3rd party users.

It adds two new dependencies:
 * libsoup to download the rates
 * libxml2 to parse the downloaded file. While the Glib "XML-like" parser could probably do it, I don't feel comfortable using something with warnings written in that big letters, and using regex to parse XML is Evil.

Since the usage of those are very limited, they could be replaced relatively easily.

works well for me.  Note you can also type these conversions into the display, e.g.:
"5 EUR in USD"