From f6f3eaa36d8d1747b43dcadd326f412c1b48c865 Mon Sep 17 00:00:00 2001
From: Alex Arslan <ararslan@comcast.net>
Date: Fri, 25 Sep 2026 17:00:02 -0700
Subject: [PATCH 1/2] Support arbitrary `AbstractIrrational`s

The fallback method had been using `Irrational{T}`, but irrational
values needn't be `Irrational`s, so we can just use `AbstractIrrational`
for that method instead.

Fixes issue 100
---
 src/Quadmath.jl  | 2 +-
 test/runtests.jl | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/Quadmath.jl b/src/Quadmath.jl
index ca5fed3..8c92568 100644
--- a/src/Quadmath.jl
+++ b/src/Quadmath.jl
@@ -465,7 +465,7 @@ end
 
 Float128(::Irrational{:π}) =  reinterpret(Float128, 0x4000921fb54442d18469898cc51701b8)
 Float128(::Irrational{:ℯ}) =  reinterpret(Float128, 0x40005bf0a8b1457695355fb8ac404e7a)
-Float128(x::Irrational{T}) where {T} = Float128(BigFloat(x))
+Float128(x::AbstractIrrational) = Float128(BigFloat(x))
 
 import Base.MPFR
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 49c81ac..1bf8da5 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -202,11 +202,18 @@ end
     @test parse(Float128,"3.0") == Float128(3.0)
 end
 
+struct TwoPi <: AbstractIrrational
+end
+Base.BigFloat(::TwoPi; precision=precision(BigFloat)) =
+    setprecision(() -> 2 * big(π), BigFloat, precision)
+Base.Float64(x::TwoPi) = Float64(big(x))
+
 @testset "irrationals" begin
     tiny = 2eps(Float128(1))
     @test abs(cos(Float128(pi)) + 1) < tiny
     @test abs(log(Float128(ℯ)) - 1) < tiny
     @test abs((2*Float128(MathConstants.golden) - 1)^2 - 5) < 5 * tiny
+    @test abs(cos(Float128(TwoPi())) - 1) < tiny
 end
 
 @testset "rationals" begin

From d58fb5e873a598e5e0ad821b35a579c3c651662f Mon Sep 17 00:00:00 2001
From: Alex Arslan <ararslan@comcast.net>
Date: Mon, 28 Sep 2026 12:47:59 -0700
Subject: [PATCH 2/2] Set precision in irrational method, test multiple
 precisions

---
 src/Quadmath.jl  |  2 +-
 test/runtests.jl | 13 +++++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/Quadmath.jl b/src/Quadmath.jl
index 8c92568..0d2b8d7 100644
--- a/src/Quadmath.jl
+++ b/src/Quadmath.jl
@@ -465,7 +465,7 @@ end
 
 Float128(::Irrational{:π}) =  reinterpret(Float128, 0x4000921fb54442d18469898cc51701b8)
 Float128(::Irrational{:ℯ}) =  reinterpret(Float128, 0x40005bf0a8b1457695355fb8ac404e7a)
-Float128(x::AbstractIrrational) = Float128(BigFloat(x))
+Float128(x::AbstractIrrational) = Float128(BigFloat(x; precision=128))
 
 import Base.MPFR
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 1bf8da5..4d60ead 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -210,10 +210,15 @@ Base.Float64(x::TwoPi) = Float64(big(x))
 
 @testset "irrationals" begin
     tiny = 2eps(Float128(1))
-    @test abs(cos(Float128(pi)) + 1) < tiny
-    @test abs(log(Float128(ℯ)) - 1) < tiny
-    @test abs((2*Float128(MathConstants.golden) - 1)^2 - 5) < 5 * tiny
-    @test abs(cos(Float128(TwoPi())) - 1) < tiny
+    default = precision(BigFloat)
+    for prec in (default, 16)
+        setprecision(BigFloat, prec)
+        @test abs(cos(Float128(pi)) + 1) < tiny
+        @test abs(log(Float128(ℯ)) - 1) < tiny
+        @test abs((2*Float128(MathConstants.golden) - 1)^2 - 5) < 5 * tiny
+        @test abs(cos(Float128(TwoPi())) - 1) < tiny
+    end
+    setprecision(default)
 end
 
 @testset "rationals" begin