TypeError:fn.atan2 is not a function
Could you provide a screenshot of how you're getting this error?
Yup, I'm looking into it. The underlying scheme-number.js code supports atan2, so it's just some simple (he says) interface issue.
This will work the same as the atan2 function and will work even when Bignums are turned on.
Edit: It only works if both numbers are positive. I'm figuring out in a new way.
And the great circle of life goes around for another cycle 
No, you have to treat divisor=0 specially regardless of the value of dividend.
something equals 0->goes parrel with grid
If the divisor = 0 then the angle is vertical regardless of the value of the divisor. If you then draw a line segment or ray starting at the sprite's current position, rather than a line, the direction of the ray or segment will follow the sign of the dividend, up if positive, down if negative.
If the dividend = 0 and the divisor ≠ 0, then you're asking for atan of 0, and the result will be horizental, with the direction following the sign of the divisor.
yeah thats what i mean(parrel with one of axis means either vertical or horizontal
Yes, but you didn't explain it in enough detail for someone to implement it correctly.
oh ok
anyways this is a bug report