Support rounding Irrationals (#45598)

Author: theabhirath

base/float.jl

@@ -379,11 +379,6 @@ trunc(::Type{Signed}, x::IEEEFloat) = trunc(Int,x)
 trunc(::Type{Unsigned}, x::IEEEFloat) = trunc(UInt,x)
 trunc(::Type{Integer}, x::IEEEFloat) = trunc(Int,x)
 
-# fallbacks
-floor(::Type{T}, x::AbstractFloat) where {T<:Integer} = trunc(T,round(x, RoundDown))
-ceil(::Type{T}, x::AbstractFloat) where {T<:Integer} = trunc(T,round(x, RoundUp))
-round(::Type{T}, x::AbstractFloat) where {T<:Integer} = trunc(T,round(x, RoundNearest))
-
 # Bool
 trunc(::Type{Bool}, x::AbstractFloat) = (-1 < x < 2) ? 1 <= x : throw(InexactError(:trunc, Bool, x))
 floor(::Type{Bool}, x::AbstractFloat) = (0 <= x < 2) ? 1 <= x : throw(InexactError(:floor, Bool, x))

base/floatfuncs.jl

@@ -154,6 +154,14 @@ trunc(x::Real; kwargs...) = round(x, RoundToZero; kwargs...)
 floor(x::Real; kwargs...) = round(x, RoundDown; kwargs...)
 ceil(x::Real; kwargs...)  = round(x, RoundUp; kwargs...)
 
+# fallbacks
+trunc(::Type{T}, x::Real; kwargs...) where {T} = round(T, x, RoundToZero; kwargs...)
+floor(::Type{T}, x::Real; kwargs...) where {T} = round(T, x, RoundDown; kwargs...)
+ceil(::Type{T}, x::Real; kwargs...) where {T} = round(T, x, RoundUp; kwargs...)
+round(::Type{T}, x::Real; kwargs...) where {T} = round(T, x, RoundNearest; kwargs...)
+
+round(::Type{T}, x::Real, r::RoundingMode) where {T} = convert(T, round(x, r))
+
 round(x::Integer, r::RoundingMode) = x
 
 # round x to multiples of 1/invstep

base/missing.jl

@@ -146,6 +146,7 @@ round(::Type{T}, ::Missing, ::RoundingMode=RoundNearest) where {T} =
     throw(MissingException(missing_conversion_msg(T)))
 round(::Type{T}, x::Any, r::RoundingMode=RoundNearest) where {T>:Missing} = round(nonmissingtype_checked(T), x, r)
 # to fix ambiguities
+round(::Type{T}, x::Real, r::RoundingMode=RoundNearest) where {T>:Missing} = round(nonmissingtype_checked(T), x, r)
 round(::Type{T}, x::Rational{Tr}, r::RoundingMode=RoundNearest) where {T>:Missing,Tr} = round(nonmissingtype_checked(T), x, r)
 round(::Type{T}, x::Rational{Bool}, r::RoundingMode=RoundNearest) where {T>:Missing} = round(nonmissingtype_checked(T), x, r)
 
@@ -158,6 +159,7 @@ for f in (:(ceil), :(floor), :(trunc))
         ($f)(::Type{T}, x::Any) where {T>:Missing} = $f(nonmissingtype_checked(T), x)
         # to fix ambiguities
         ($f)(::Type{T}, x::Rational) where {T>:Missing} = $f(nonmissingtype_checked(T), x)
+        ($f)(::Type{T}, x::Real) where {T>:Missing} = $f(nonmissingtype_checked(T), x)
     end
 end
 

base/rational.jl

@@ -484,10 +484,6 @@ for (S, T) in ((Rational, Integer), (Integer, Rational), (Rational, Rational))
     end
 end
 
-trunc(::Type{T}, x::Rational) where {T} = round(T, x, RoundToZero)
-floor(::Type{T}, x::Rational) where {T} = round(T, x, RoundDown)
-ceil(::Type{T}, x::Rational) where {T} = round(T, x, RoundUp)
-
 round(x::Rational, r::RoundingMode=RoundNearest) = round(typeof(x), x, r)
 
 function round(::Type{T}, x::Rational{Tr}, r::RoundingMode=RoundNearest) where {T,Tr}

test/numbers.jl

@@ -1168,6 +1168,17 @@ Base.@irrational i46051 4863.185427757 1548big(pi)
     # issue #46051
     @test sprint(show, "text/plain", i46051) == "i46051 = 4863.185427757..."
 end
+
+@testset "Irrational round, float, ceil" begin
+    using .MathConstants
+    @test round(π) === 3.0
+    @test round(Int, ℯ) === 3
+    @test floor(ℯ) === 2.0
+    @test floor(Int, φ) === 1
+    @test ceil(γ) === 1.0
+    @test ceil(Int, catalan) === 1
+end
+
 @testset "issue #6365" begin
     for T in (Float32, Float64)
         for i = 9007199254740992:9007199254740996