From d6e9985a266c1298f1a2a3a5831945150c269d88 Mon Sep 17 00:00:00 2001
From: Dmitry Atamanov <dataman@tutanota.com>
Date: Fri, 15 Sep 2023 11:44:09 +0500
Subject: [PATCH] Add `log(x, base)` function to `std::math` module.

---
 lib/std/math/math.c3          | 14 ++++++++---
 releasenotes.md               |  3 ++-
 test/unit/stdlib/math/math.c3 | 47 ++++++++++++++++++++++-------------
 3 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/lib/std/math/math.c3 b/lib/std/math/math.c3
index 4a032ac6b..752438ec3 100644
--- a/lib/std/math/math.c3
+++ b/lib/std/math/math.c3
@@ -310,8 +310,8 @@ macro floor(x) => $$floor(values::promote_int(x));
  * @require values::@is_promotable_to_floatlike(a) `The input must be a number or float vector`
  * @require values::@is_promotable_to_floatlike(b) `The input must be a number or float vector`
  * @require values::@is_promotable_to_floatlike(c) `The input must be a number or float vector`
- * @require types::@is_same_vector_type(a, b) `The input types must be equal`
- * @require types::@is_same_vector_type(a, c) `The input types must match`
+ * @require values::@is_same_vector_type(a, b) `The input types must be equal`
+ * @require values::@is_same_vector_type(a, c) `The input types must match`
  **/
 macro fma(a, b, c) => $$fma(a, b, c);
 
@@ -319,14 +319,20 @@ macro fma(a, b, c) => $$fma(a, b, c);
 /**
  * @require values::@is_promotable_to_floatlike(x) `The input must be a number or a float vector`
  * @require values::@is_promotable_to_floatlike(y) `The input must be a number or a float vector`
- * @require types::@is_same_vector_type(x, y) `The input types must match`
+ * @require values::@is_same_vector_type(x, y) `The input types must match`
  **/
 macro hypot(x, y) => sqrt(sqr(x) + sqr(y));
 
 /**
  * @require values::@is_promotable_to_floatlike(x) `The input must be a number or a float vector`
  **/
-macro log(x) => $$log(values::promote_int(x));
+macro ln(x) => $$log(values::promote_int(x));
+
+/**
+ * @require values::@is_promotable_to_floatlike(x) `The input must be a number or a float vector`
+ * @require values::@is_promotable_to_floatlike(base) `The base must be a number or a float vector`
+ **/
+macro log(x, base) => $$log(values::promote_int(x)) / $$log(values::promote_int(base));
 
 /**
  * @require values::@is_promotable_to_floatlike(x) `The input must be a number or a float vector`
diff --git a/releasenotes.md b/releasenotes.md
index 1e2ff2a33..02b602010 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -116,8 +116,9 @@
 - Update addition and subtraction on enums.
 - `@ensure` checks only non-optional results.
 - `assert` may now take varargs for formatting.
- 
+
 ### Stdlib changes
+- Added `math::log(x , base)` and `math::ln(x)`.
 - Hashmap keys implicitly copied if copy/free are defined.
 - Socket handling.
 - `csv` package.
diff --git a/test/unit/stdlib/math/math.c3 b/test/unit/stdlib/math/math.c3
index 2bcdc1d8c..a176ec7a4 100644
--- a/test/unit/stdlib/math/math.c3
+++ b/test/unit/stdlib/math/math.c3
@@ -16,23 +16,6 @@ fn void! test_abs() @test
 	assert(math::abs(yy) == double[<3>] { 1, 0.5, 1000 });
 }
 
-fn void! test_sign() @test
-{
-	int x = -21;
-	assert(math::sign(x) == -1);
-	x = 238219382;
-	assert(math::sign(x) == 1);
-	x = 0;
-	assert(math::sign(x) == 0);
-	uint y = 23;
-	assert(math::sign(y) == 1);
-	y = 0;
-	assert(math::sign(y) == 0);
-	y = (uint)-21;
-	assert(math::sign(y) == 1);
-	assert(@typeis(math::sign(y), uint));
-}
-
 fn void! test_atan() @test
 {
 	int x = 231;
@@ -109,6 +92,36 @@ fn void! test_floor() @test
 	assert(math::floor(vec) == double[<5>] { -124, 123, 0, -1, 0 });
 }
 
+fn void! test_log() @test
+{
+	double x = math::E;
+	assert(math::log(x, x) == 1.0);
+	float y = math::E;
+	assert(math::log(y, y) == 1.0f);
+	$assert @typeis(math::log(y, y), float);
+	double[<3>] xx = { 2, 4, 8 };
+	assert(math::log(xx, 2) == double[<3>] { 1.0, 2.0, 3.0 });
+	float[<3>] yy = { 10, 100, 1000 };
+	assert(math::log(yy, 10) == float[<3>] { 1.0, 2.0, 3.0 });
+}
+
+fn void! test_sign() @test
+{
+	int x = -21;
+	assert(math::sign(x) == -1);
+	x = 238219382;
+	assert(math::sign(x) == 1);
+	x = 0;
+	assert(math::sign(x) == 0);
+	uint y = 23;
+	assert(math::sign(y) == 1);
+	y = 0;
+	assert(math::sign(y) == 0);
+	y = (uint)-21;
+	assert(math::sign(y) == 1);
+	assert(@typeis(math::sign(y), uint));
+}
+
 fn void! test_trunc() @test
 {
 	double d = -123.9;