TouchPlot 3.2 will soon replace 3.1 version. While
TouchPlot 2.2 added important simplifications in the
formula editor, TouchPlot 3.2 adds even more.

Keyboards are now six rows tall :

Most of the buttons should be self-explanatory but some
deserve some information :

on the first row, first button change action for most of
the buttons. The two arrows next to it allows one to select
one part of a formula for selection, moving along the
formula one item at a time. Note that when 2nd is enabled,
the left arrow selects the entire formula, and the right
one deselects...

The Vars button adds one row to insert a variable amongst
a,b,c,d. Those variables can be adjusted with the Constants
menu, as well as live on the graph view if sliders for
a,b,c or d were enabled.

The last button is the undo button, allowing one to remove
the last entered item. Note that when there is a selection,
its action will be to delete the selection, always asking
for confirmation. Note too that when deleting a selection,
the undo trace is deleted as well, so the undo button will
become inactive, and it will only undo subsequent insertion
of items in the formula.

Note that in the second row is :

which allows one to enter a numeric const in a formula. (A
numeric pad will appear for that.)

For single digit number, such as 1,2,3,4,5, some shortcuts
have been provided to speed up formula entry.

The main difference with previous versions of TouchPlot as
regards the formula editor is the possibility offered to
select a part of a formula.

Supposing one is defining h function, by composing :

one gets

then using the left selection arrow, we select the last
entered item, that is, x and get :

In such a mode (selection mode), the behavior of the editor
is the following :

- the undo button deletes the selection

- adding a const (a variable, a number) it is multiplied to
the selection

- entering a function inserts the function, making the
selection the operand of the function inserted. (so
inserting sin in the example above, one gets exp(sin(x)) of
course).

- entering an operator makes the selection the first
operand of the operator, so inserting + in the example
above we get this :

You notice of course the change of color. There is no
selection anymore, but a red color showing the editing is
now locked inside the exponential function. Subsequent
entries will complete the exponential argument. To exit the
lock, just use the right arrow.

It is now very easy to enter an expression such as
(2x^3+x+1)/(x^2-x+1). It is of course still possible to use
polish notation from beginning to the end, but the fastest
here would probably be :

so that we get :

By selecting the numerator, we will first fill the blank
with the first item, and remain editing the numerator until
we decide otherwise.

So we have the numerator, and the formula display shows :

Now that we finished entering the numerator, we exit the
lock with

and we get

Notice that the lock has not disappeared, but has just
moved to the denominator, which is perfect for what we need
now... We just enter the denominator then with :

There are many other equivalent ways to enter this function
with touchplot 3.2... I let you find them !