Add Base.round(x::IrrationalConstant, r::RoundingMode) (#24)

* add `Base.round(x::IrrationalConstant, r::RoundingMode)`

* Add tests

* More tests

* Revert unrelated changes

---------

Co-authored-by: David Widmann <david.widmann@it.uu.se>
Co-authored-by: David Widmann <devmotion@users.noreply.github.com>

Author: hyrodium

Project.toml

@@ -1,7 +1,7 @@
 name = "IrrationalConstants"
 uuid = "92d709cd-6900-40b7-9082-c6be49f344b6"
 authors = ["JuliaMath"]
-version = "0.2.0"
+version = "0.2.1"
 
 [compat]
 julia = "1"

src/macro.jl

@@ -4,6 +4,8 @@
 
 abstract type IrrationalConstant <: AbstractIrrational end
 
+# TODO: Remove definitions if they become available for `AbstractIrrational` in Base
+# Ref https://github.com/JuliaLang/julia/pull/48768
 function Base.show(io::IO, ::MIME"text/plain", x::IrrationalConstant)
     if get(io, :compact, false)::Bool
         print(io, x)
@@ -16,6 +18,7 @@ Base.:(==)(::T, ::T) where {T<:IrrationalConstant} = true
 Base.:<(::T, ::T) where {T<:IrrationalConstant} = false
 Base.:<=(::T, ::T) where {T<:IrrationalConstant} = true
 Base.hash(x::IrrationalConstant, h::UInt) = 3*objectid(x) - h
+Base.round(x::IrrationalConstant, r::RoundingMode) = round(float(x), r)
 
 # definitions for AbstractIrrational added in https://github.com/JuliaLang/julia/pull/34773
 if VERSION < v"1.5.0-DEV.301"

test/runtests.jl

@@ -131,3 +131,22 @@ end
     @test twoπ/ComplexF32(2) isa ComplexF32
     @test log(twoπ, ComplexF32(2)) isa ComplexF32
 end
+
+# issue #23
+@testset "rounding irrationals" begin
+    # without rounding mode
+    @test @inferred(round(twoπ)) == 6.0
+    @test @inferred(round(sqrt2)) == 1.0
+    @test @inferred(round(sqrt3)) == 2.0
+    @test @inferred(round(loghalf)) == -1.0
+
+    # with rounding modes
+    for mode in (RoundDown, RoundToZero, RoundNearest, RoundNearestTiesAway, RoundNearestTiesUp)
+        @test @inferred(round(twoπ, mode)) == 6.0
+        @test @inferred(round(sqrt2, mode)) == 1.0
+    end
+    @test @inferred(round(sqrt3, RoundUp)) == 2.0
+    for mode in (RoundUp, RoundToZero)
+        @test @inferred(round(loghalf, mode)) == 0.0
+    end
+end