From 75802b6408842e4f59521bd52e72237ef31cd64e Mon Sep 17 00:00:00 2001
From: inoas <mail@inoas.com>
Date: Mon, 11 Apr 2022 23:54:33 +0200
Subject: wip

---
 src/gleam/float.gleam | 21 +++++++++++++++------
 src/gleam/int.gleam   | 28 +++++++++++++++++++++++++++-
 src/gleam_stdlib.mjs  |  2 +-
 3 files changed, 43 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/gleam/float.gleam b/src/gleam/float.gleam
index 4c314a9..20fd6c8 100644
--- a/src/gleam/float.gleam
+++ b/src/gleam/float.gleam
@@ -321,10 +321,11 @@ fn do_product(numbers: List(Float), initial: Float) -> Float {
   }
 }
 
-/// Returns a random value where 0.0 =< value < 1.0
+/// Returns a uniform random number
+/// Thus where 0.0 =< value < 1.0
 ///
-pub fn random() -> Float {
-  do_random()
+pub fn random_uniform() -> Float {
+  do_random_uniform()
 }
 
 if erlang {
@@ -332,7 +333,7 @@ if erlang {
   // 0.0 =< X < 1.0 and updates the state in the process dictionary.
   /// See: <https://www.erlang.org/doc/man/rand.html#uniform-0>
   ///
-  external fn do_random() -> Float =
+  external fn do_random_uniform() -> Float =
     "rand" "uniform"
 }
 
@@ -344,6 +345,14 @@ if javascript {
   /// Note that as numbers in JavaScript are IEEE 754 floating point numbers
   /// See: <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random>
   ///
-  external fn do_random() -> Float =
-    "../gleam_stdlib.mjs" "random"
+  external fn do_random_uniform() -> Float =
+    "../gleam_stdlib.mjs" "random_uniform"
+}
+
+pub fn random_between(min: Float, max: Float) -> Float {
+  // ```javascript
+  // return Math.floor(Math.random() * (max - min + 1) + min); // The maximum is/shuould-be exclusive
+  // ```
+  // See: <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random#getting_a_random_number_between_two_values>
+  random_uniform() *. { max -. min } +. min
 }
diff --git a/src/gleam/int.gleam b/src/gleam/int.gleam
index c60affb..9da5c97 100644
--- a/src/gleam/int.gleam
+++ b/src/gleam/int.gleam
@@ -1,4 +1,6 @@
 import gleam/order.{Order}
+// import gleam/float.{floor, parse, random}
+import gleam/float
 
 /// Returns the absolute value of the input.
 ///
@@ -324,7 +326,7 @@ fn do_product(numbers: List(Int), initial: Int) -> Int {
   }
 }
 
-/// Splits an integer into its digit representation in the specified base 
+/// Splits an integer into its digit representation in the specified base
 ///
 /// ## Examples
 ///
@@ -380,3 +382,27 @@ fn do_undigits(
     [digit, ..rest] -> do_undigits(rest, base, acc * base + digit)
   }
 }
+
+pub fn random_below(max: Int) -> Int {
+  // ```javascript
+  // return Math.floor(rand * max);
+  // ```
+  // See: <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random>
+  float.random_uniform() *. to_float(max)
+  |> float.floor()
+  |> float.round()
+  // Does `float.round() `affect random distribution uniformity?
+}
+
+pub fn random_between(min: Int, max: Int) -> Int {
+  // ```javascript
+  // min = Math.ceil(min);
+  // max = Math.floor(max);
+  // return Math.floor(Math.random() * (max - min + 1) + min); //The maximum is
+  // ```
+  // See: <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random#getting_a_random_integer_between_two_values>
+  float.random_between(to_float(min), to_float(max))
+  |> float.floor()
+  |> float.round()
+  // Does float.round() affect random distribution uniformity?
+}
diff --git a/src/gleam_stdlib.mjs b/src/gleam_stdlib.mjs
index 5d80640..59077e9 100644
--- a/src/gleam_stdlib.mjs
+++ b/src/gleam_stdlib.mjs
@@ -246,7 +246,7 @@ export function power(base, exponent) {
   return Math.pow(base, exponent);
 }
 
-export function random() {
+export function random_uniform() {
   return Math.random();
 }
 
-- 
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