Minor fixes

+ add more docs
+ add more types to Kernel (i16, i128, isize)

Author: rmanoka

geo/Cargo.toml

@@ -34,8 +34,6 @@ use-serde = ["serde", "geo-types/serde"]
 [dev-dependencies]
 approx = "0.3.0"
 criterion = { version = "0.3" }
-png = "0.16.7"
-float_extras = "0.1.6"
 
 [[bench]]
 name = "area"

geo/src/algorithm/kernels/mod.rs

@@ -45,7 +45,11 @@ pub trait HasKernel: CoordinateType {
     type Ker: Kernel<Scalar = Self>;
 }
 
-#[macro_export]
+// Helper macro to implement `HasKernel` on a a scalar type
+// `T` (first arg.) by assigning the second arg. It expects
+// the second arg. to be a type that takes one generic
+// parameter that is `T`.
+#[macro_use]
 macro_rules! has_kernel {
 	  ($t:ident, $k:ident) => {
         impl $crate::algorithm::kernels::HasKernel for $t {
@@ -59,8 +63,13 @@ pub use self::robust::RobustKernel;
 has_kernel!(f64, RobustKernel);
 has_kernel!(f32, RobustKernel);
 
-
 pub mod simple;
 pub use self::simple::SimpleKernel;
+
 has_kernel!(i64, SimpleKernel);
 has_kernel!(i32, SimpleKernel);
+has_kernel!(i16, SimpleKernel);
+has_kernel!(isize, SimpleKernel);
+
+#[cfg(has_i128)]
+has_kernel!(i128, SimpleKernel);

geo/src/utils.rs

@@ -127,8 +127,10 @@ where
     }
 }
 
-/// Compute index of the lexicographically least point.
-/// Should only be called on a non-empty slice.
+/// Compute index of the lexicographically least point. In
+/// other words, point with minimum `x` coord, and breaking
+/// ties with minimum `y` coord. Should only be called on a
+/// non-empty slice with no `nan` coordinates.
 pub fn lexicographically_least_index<T: Copy + PartialOrd>(pts: &[T]) -> usize {
     assert!(pts.len() > 0);