add TwoSided

Project.toml

@@ -1,7 +1,7 @@
 name = "Uncertain"
 uuid = "b33f403f-199b-472b-b9d0-1cd2092892d0"
 authors = ["Alexander Plavin <alexander@plav.in>"]
-version = "0.1.3"
+version = "0.1.4"
 
 [deps]
 Accessors = "7d9f7c33-5ae7-4f3b-8dc6-eff91059b697"

src/Uncertain.jl

@@ -8,6 +8,7 @@ include("types.jl")
 include("show.jl")
 include("maths.jl")
 include("agg.jl")
+include("twosided.jl")
 include("disambiguation.jl")
 
 """    ±ᵤ(val, unc)
@@ -54,7 +55,8 @@ export Value, ValueAny, ValueNumber, ValueReal, value, uncertainty, nσ, weighte
 using ..Uncertain:
     Value, ValueAny, ValueNumber, ValueReal,
     value, uncertainty, nσ,
-    weightedmean
+    weightedmean,
+    TwoSided, width, maxdiff
 using ..Uncertain: ±ᵤ as ±
 end
 

src/twosided.jl

@@ -0,0 +1,25 @@
+"""    TwoSided{T}(lo::T, hi::T)
+
+Asymmetric two-sided uncertainty: `lo` is the uncertainty in the lower direction, and `hi` in the upper direction.
+Both `lo` and `hi` should be positive.
+
+Uncertainty of `TwoSided(x, x)` should behave like just `x`. Only makes sense for numbers with a natural order.
+"""
+struct TwoSided{T}
+    lo::T
+    hi::T
+end
+
+Base.show(io::IO, u::TwoSided) = print(io, "TwoSided(", u.lo, ", ", u.hi, ")")
+
+Base.float(::Type{TwoSided{T}}) where {T} = TwoSided{float(T)}
+
+Base.:*(a::TwoSided, b) = @modify(p -> p * b, a[∗ₚ])
+Base.:*(a, b::TwoSided) = @modify(p -> a * p, b[∗ₚ])
+
+for f in [:rad2deg, :deg2rad]
+    @eval Base.$f(a::TwoSided) = @modify($f, a[∗ₚ])
+end
+
+width(a::TwoSided) = a.lo + a.hi
+maxdiff(a::TwoSided) = max(a.lo, a.hi)

test/twosided.jl

@@ -0,0 +1,15 @@
+@testitem "one vs two sided" begin
+    using Unitful
+
+    @test U.width(0.1) == 0.2
+    @test U.maxdiff(0.1) == 0.1
+
+    @test U.width(U.TwoSided(0.1, 0.2)) ≈ 0.3
+    @test U.maxdiff(U.TwoSided(0.1, 0.2)) == 0.2
+    @test U.maxdiff(U.TwoSided(0.2, 0.1)) == 0.2
+
+    @test U.TwoSided(0.1, 0.2) * 2 == U.TwoSided(0.2, 0.4)
+    @test 2 * U.TwoSided(0.1, 0.2) == U.TwoSided(0.2, 0.4)
+    @test U.TwoSided(0.1, 0.2) * u"m" == U.TwoSided(0.1u"m", 0.2u"m")
+    @test 1u"m" * U.TwoSided(0.1, 0.2) == U.TwoSided(0.1u"m", 0.2u"m")
+end