Call it my Mac Gyver tip of the week (in a french blog, the tip to check the online status of the server with ecblank.gif/onerror-event was called something like that).
I've sometimes got really fed up developing formulas for computed fields, view columns, transforming dblookups, you name it. Just the other day, I thought this one up.
Make a form with an editable input field. Make a hidden SaveOptions-field (computed for display, default value="0").
The editable field is where you type formula-code. The nice thing about notes-fields is that they are multi-line, so you can write quite complicated formulas.
Below the text, write Result: or something like that. Then add a computed text with this formula:
F9 (refresh) to execute the formula.. TaDa! You have your own formula-console.. :)
I have added a toolbar-button in the designer and client, so that I have instant access to the "console".
A little update: If you use a button to @Eval the text-field, you can also execute some UI-formulas, that you can't execute from a computed text.