Read commandline arguments

[Clueid]

In any programming language, it's possible to read commands and options from cli. E.g:

python myprogram.py arg1 arg2 arg3

How can I do the same in Asymptote? Simple example: a file named circle.asy draws a circle with radius r where r is read from the cli like this: asy circle.asy 1.7. Output: circle with radius 1.7 units.

[John Bowman]

Here's an example:

asy -V test -u r=1.7

where test.asy contains

unitsize(1cm);

real r=1;

usersetting();
draw(circle((0,0),r));