[Tutor] Better structure?

[Jacob S.]

>> def start():
>      .... lots of lines...
>>     global xaxis
>>     global yaxis
>
> Its traditional to put global statements at the top of the function.
> Also you only need one line to list all of the global variables
>
>>     global radiusaxis
>>     global radiusaxis2

What, like
global radiusaxis, radiusaxis2

> Similarly here., and again you can put all four in one place.
>
>>     radiusaxis2.visible = 0

> And since there is no input parameter and no return statement
> and you only call start() once...

Not true. If y == 'clear', then start is called to "redraw" the window.
Very important part.

>> def graphit(type,f,range2,step):
>>     li = curve(color=color.blue)
>>     if type in ['y','x']:
>>         x = -15
>>         radiusaxis.visible = 0
>>         radiusaxis2.visible = 0
>>         while -15 <= x <= 15:
>>             if eval(range2):
>>                 try:
>>                     a = f(x)
>>                     if -15 <= a <= 15:
>>                         if type == 'y':
>>                             li.append(pos=(x,a,0))
>>                         elif type == 'x':
>>                             li.append(pos=(a,x,0))
>>                     else:
>>                         li = curve(color=color.blue)
>>                 except:
>>                     pass
>
> This is iffy. If *anthing* happens you ignore it.
> Now suppose due to a bug you go into an infinite
> loop and you try to stop using CTRL-C -  it won't work!
>
> If you must use a catch-all except then do something
> with it - print a message at least!

I think I'll do that, but of course I'll have to add ValueError -- because 
of math domain errors on
my function. That's what the try except block is for. Otherwise I wouldn't 
need it.


> I got a sore head after that... I'll leave the rest for
> others to remark upon. :-)
>
> Alan G.

I'd send some Advil or something, but it doesn't work too well through 
email. ;-)
Thanks for the help,
Jacob Schmidt