From e79dc41c058a94230ea1c71cb742f7645da756a3 Mon Sep 17 00:00:00 2001
From: Julien Reichardt <git@jrei.ch>
Date: Wed, 6 Jan 2021 15:53:15 +0100
Subject: [PATCH] Add Math::TAU (#10179)

* Add Math::TAU

* Add doc comments to Math constants
---
 src/math/math.cr | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/math/math.cr b/src/math/math.cr
index d56de5ce0ac7..49bcd91b353d 100644
--- a/src/math/math.cr
+++ b/src/math/math.cr
@@ -3,7 +3,11 @@ require "./libm"
 module Math
   extend self
 
-  PI    = 3.14159265358979323846
+  # Archimedes' constant (π).
+  PI = 3.14159265358979323846
+  # The full circle constant (τ), equal to 2π.
+  TAU = 6.283185307179586476925
+  # Euler's number (e).
   E     = LibM.exp_f64(1.0)
   LOG2  = LibM.log_f64(2.0)
   LOG10 = LibM.log_f64(10.0)