Re: [Flightgear-devel] Flasher in nasal

[Melchior F. <mf...@ao...>]

* Roy Vegard Ovesen -- Friday 06 April 2007:
> I assumed that it was possible to name the arguments when calling the 
> function, like in Python. And that you could then give them in arbitrary 
> order.

No, that's not the case in Nasal.


 
> How do I add a <repeat> argument to the aircraft.light.new method? If I add it 
> before <switch> then that will certainly break things. If I add it after 
> <switch> then <switch> is no longer optional.

And that's the reason for the type checking.  :-)



> Another solution would be to set the last element of the pattern to the number 
> of times to repeat the pattern, -1 meaning repeat forever. [...]
> Third option is to set the last element in pattern to the negative number of 
> times to repeat. [0.5, 0.5, -3], 

No. I don't think that this belongs to the constructor at all. It's
an action on the light/flasher device, and nothing that defines the device.
I think the best way is to interpret the switch() method parameter like so:

  foo.switch(1)   ... turn on  (or any other value >0)
  foo.switch(0)   ... turn off
  foo.switch(-2)  ... turn on for two cycles

This doesn't break compatibility (who used negative number?), and it even
looks like "up to 2 times", or from 0-2. And if you want that to be define
at construction time, then you can still write:

  var foo = aircraft.light.new("something", [1,1,1,1]).switch(-10);

... as the switch method returns "me".

m.