Note that this tutorial only applies to the old style editor. This one is still available in TouchPlot 4 provided you edit Touchplot’s application preference (Settings application). For the new editor, have a look at the movies for version 4.0, or at the embedded documentation.

Designing a formula editor is not an easy task, and the absence of a physical keyboard on the iPhone or iPod touch doesn't make it any easier. I decided to use direct polish notation to enter a formula. It has the benefit of not needing to enter any parenthesis and minimizing the number of touches... It has a drawback though, one needs some time to get used to it !

Rather than describe it in theory, lets just study some examples : to enter a formula using direct polish notation, you have some work to do : you have to analyse the formula and be able to tell : this is a sum, this is a product, this is the sinus of something... Then you have it : if it is a sum, you hit +, then you compose the left part of the sum, then the right part.

Note that since version 2.2, and even more with 3.2 version, things have become much easier for those having difficulties with polish notation. One could even enter a formula never using polish notation, but the most convenient and fast way still remains using direct polish notation.