Pippy and Calculate - Evolution Solution

[Albert Cahalan]

Yoshiki Ohshima writes:
> Hi, Steve,

>> I am a lurker, but this is an interesting discussion.  I am a
>> developer in health applications working with current dev release on a
>> B4.  Calculate is impressive; Pippy is impressive.  They each serve a
>> purpose which I think fits into an OPLC evolutionist philosophy.
>
>   But, have you actually tried to use Calculate?  It could not detect
> simple errors properly (which is now fixed), takes 10 seconds to
> calculate "3+4", and digits in a long floating point number are
> wrapped around, etc.?

Errors ought to be detected as typed, with the text changing
color at the point where syntax is violated. So this...

7+5-9*4)-5

...would be highlighted starting from the ')' character.

It may be good to display the expressions twice, once like
a normal (C, Java, C#, C++) programming language for editing
and once in a proper (TeX, MathML, textbooks) rendering.

For the math itself, I suggest feeding expressions into the "bc"
program.

>   Again, this is not a criticism toward Reinier, but rather toward the
> fact that keeping up with the rate of change that Sugar and the UI
> guideline is not something a volunteer developer can easily cope with.

Calculate is in Python, isn't it? Sugar and UI changes are deadly
for the non-Python stuff.

>> First, there are US toys that are remarkably similar to the OLPC in
>> appearance that comprise a simple 4x4 calculator aimed at the under 5
>> year old crowd.  Large keys that do arithmetic.

I think the idea of clicking on on-screen buttons is fundamentally
defective. The keyboard is far easier to use. I suggest displaying
an on-screen copy of that, with the valid keystrokes highlighted.
One could still use it with the touchpad, if one wanted to suffer.
So in the above example, after "7+5-9*4" the ')' key would not be
highlighted.

Having such an on-screen representation would make it easy to
show letter keys remapped as appropriate. For example, a key
might serve as sin() normally or as arcsin() when control is
used. (BTW, control might be made sticky)

>   Well, if you consider under 5 years old crowd, then you would oppose
> to have variables in Calculate?  (BTW, OLPC is not aimed at the crowd,
> I believe.)  What do you think about the the use of e-notation in it?
> How about all these functions available in the tab?

Arbitrary named variables are probably not good. Cut-and-paste gives
you a variable, and the most recent answer (or two) could implicitly
be a variable. If there is a scrolling log of answers, clicking on
lines of the log could act as variables. Anything beyond that is
probably getting into spreadsheet territory, but there are low-complexity
ways to deal with that too: cut-and-paste to a text document, allow
drag-and-drop to a saved-data area of the screen, or just scribble
on something physical.

>   Imagine if the functions that are available in the Calculate "mode"
> (such as sin, sqrt, etc.) are actually defined in a way that kids can
> understand (for example, the Newton-method for sqrt, or even a
> graphical version for sin and cos), and if the user goes to the Pippy
> "mode", the user can look inside the definition and modify them?  That
> would be very constructionist.

Dear my. I'm all in favor of supporting the bright kids, but that
suggestion sounds like grade 12 honors at minimum.