From e3d91921554fd273687a2ac514cb1023b7b69bb7 Mon Sep 17 00:00:00 2001
From: Lucien Grondin <grondilu@outlook.fr>
Date: Sat, 13 May 2023 10:20:53 +0200
Subject: [PATCH] pin-point one half case

---
 META6.json     |  2 +-
 lib/TrigPi.pm6 | 18 ++++++++----------
 t/edges.t      | 16 ++++++++++++----
 3 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/META6.json b/META6.json
index b777d9d..86e7a64 100644
--- a/META6.json
+++ b/META6.json
@@ -2,7 +2,7 @@
     "perl" : "6.*",
     "name" : "TrigPi",
     "license" : "MIT",
-    "version" : "1.5.0",
+    "version" : "1.6.0",
     "description" : "accurate computation of sin(π*$x) and cos(π*$x)",
     "author" : "Lucien Grondin",
     "build-depends" : [ ],
diff --git a/lib/TrigPi.pm6 b/lib/TrigPi.pm6
index 595d403..df968f7 100644
--- a/lib/TrigPi.pm6
+++ b/lib/TrigPi.pm6
@@ -1,26 +1,24 @@
 unit module TrigPi;
 
 sub sinPi(Real $x --> Real) is export {
-    $x < 0   ?? -sinPi(-$x) !!
-    $x ≤ 1/2 ??  sin(pi*$x) !!
-    $x < 1   ??  sinPi(1 - $x) !!
-    $x < 2   ?? -sinPi($x - 1) !!
+    $x < 0  ?? -sinPi(-$x) !!
+    $x < ½  ??  sin(pi*$x) !!
+    $x == ½ ??  1 !!
+    $x < 1  ??  sinPi(1 - $x) !!
+    $x < 2  ?? -sinPi($x - 1) !!
     sinPi($x % 2)
 }
 
 sub cosPi(Real $x --> Real) is export {
     $x < 0   ??  cosPi(-$x) !!
-    $x ≤ 1/2 ??  cos(pi*$x) !!
+    $x < ½   ??  cos(pi*$x) !!
+    $x == ½  ?? 0 !!
     $x < 1   ?? -cosPi(1 - $x) !!
     $x < 2   ?? -cosPi($x - 1) !!
     cosPi($x % 2)
 }
 
 sub cisPi(Real $x --> Complex) is export {
-    $x < 0   ?? cisPi(-$x).conj !!
-    $x ≤ 1/2 ?? cis(pi*$x) !!
-    $x < 1   ?? -cisPi(1-$x).conj !!
-    $x < 2   ?? -cisPi($x-1) !!
-    cisPi($x % 2)
+   Complex.new: cosPi($x), sinPi($x);
 }
 
diff --git a/t/edges.t b/t/edges.t
index 5ed539f..23f7db9 100644
--- a/t/edges.t
+++ b/t/edges.t
@@ -1,11 +1,19 @@
 use Test;
+use lib <lib>;
 use TrigPi;
 
-plan 3*4;
+plan 2+4;
+
+ok cisPi(1/2).reals[0] == 0;
+ok cisPi(-1/2).reals[0] == 0;
 
 for <0 1/2 1 2> {
-  is-approx cisPi($_), cis(pi*$_);
-  is-approx cosPi($_), cos(pi*$_);
-  is-approx sinPi($_), sin(pi*$_);
+  subtest ~(+$_), {
+    plan 3;
+    is-approx cisPi($_), cis(pi*$_);
+    is-approx cosPi($_), cos(pi*$_);
+    is-approx sinPi($_), sin(pi*$_);
+  }
 }
 
+