atan2 in std

[sciconf]

It would be great to add atan2 to std. atan2 is super useful for converting from rectangular to polar coordinates.

I think it looks something like this, but ... I'm not expert with rust at all:

--- a/crates/jrsonnet-stdlib/src/lib.rs
+++ b/crates/jrsonnet-stdlib/src/lib.rs
@@ -104,6 +104,7 @@ pub fn stdlib_uncached(settings: Rc<RefCell<Settings>>) -> ObjValue {
                ("asin", builtin_asin::INST),
                ("acos", builtin_acos::INST),
                ("atan", builtin_atan::INST),
+               ("atan2", builtin_atan2::INST),
--- a/crates/jrsonnet-stdlib/src/math.rs
+++ b/crates/jrsonnet-stdlib/src/math.rs
@@ -89,6 +89,11 @@ pub fn builtin_atan(x: f64) -> f64 {
        x.atan()
 }

+#[builtin]
+pub fn builtin_atan2(y:f64, x: f64) -> f64 {
+       y.atan2(x)
+}
+

[CertainLach]

I agree this is useful, and yes, your code is correct for that.
I have such helper in one of my projects using jsonnet for now:

local atan2(y, x) =
  if x > 0 then
    atan(y / x)
  else if x < 0 && y >= 0 then
    atan(y / x) + pi
  else if x < 0 && y < 0 then
    atan(y / x) - pi
  else if x == 0 && y > 0 then
    pi / 2
  else if x == 0 && y < 0 then
    -pi / 2
  else
    error "atan2(0, 0) is undefined"; 

But I agree this is acceptable to add this to standard library. The problem is, it should also be added to official jsonnet implementation...

[sciconf]

I also have nearly the same jsonnet atan2 code myself too, but it just seems better to be in std with all the other trig. I put a request in for the c++ library as well:
google/jsonnet#1118
But, since jrsonnet is way faster and what I actually use, this is where I'd really like it :).