implement Base.complex, Base.widen, Base.reim (PainterQubits#2)

.gitignore

@@ -4,3 +4,4 @@
 deps/
 docs/build/
 docs/site/
+*~

src/Unitful.jl

@@ -4,6 +4,7 @@ import Base: ==, <, <=, +, -, *, /, //, ^, isequal
 import Base: show, convert
 import Base: abs, abs2, angle, float, fma, muladd, inv, sqrt, cbrt
 import Base: min, max, floor, ceil, real, imag, conj
+import Base: complex, widen, reim # handled in complex.jl
 import Base: exp, exp10, exp2, expm1, log, log10, log1p, log2
 import Base: sin, cos, tan, cot, sec, csc, atan, cis
 
@@ -45,6 +46,7 @@ include("conversion.jl")
 include("range.jl")
 include("fastmath.jl")
 include("logarithm.jl")
+include("complex.jl")
 include("pkgdefaults.jl")
 
 function __init__()

src/complex.jl

@@ -0,0 +1,39 @@
+# This file is meant to provide all the methods in
+# https://github.com/JuliaLang/julia/blob/master/base/complex.jl that
+# are defined for Real or Complex numbers, just for
+# AbstractQuantities{T,D,U} where T is Real or Complex, respectively.
+#
+# It is currently incomplete.
+
+complex(z::Quantity{T,D,U}) where {T<:Complex,D,U} = z
+function complex(x::Quantity{T,D,U}, y = zero(x)) where {
+    T<:Real,D,U
+}
+    r, i = promote(x, y)
+    return Quantity{complex(T),D,U}(complex(ustrip(r), ustrip(i)))
+end
+complex(::Type{Quantity{T,D,U}}) where {T,D,U} =
+    Quantity{complex(T),D,U}
+
+# implement Base.widen for real and complex quantities because Unitful
+# does not have an implementation for widen yet
+Base.widen(::Type{Quantity{T,D,U}}) where {T,D,U} =
+    Quantity{widen(T),D,U}
+
+# skip Base.float, Base.real, Base.imag because it is already
+# implemented
+
+Base.reim(z::Quantity{T,D,U}) where {T<:Complex,D,U} =
+    (real(z), imag(z))
+
+# Base.real for types has a general implementation in julia; a faster
+# method could be provided but is not strictly required.
+
+# Base.isreal, etc., are already implemented in Unitful.
+
+# Base.flipsign is already implemented in Unitful.
+
+# To Do: Check if Base.show, Base.read, Base.write, etc. need any
+#        attention
+
+# ...

test/runtests.jl

@@ -52,6 +52,10 @@ const colon = Base.:(:)
         FixedUnits{(Unitful.Unit{:Meter, 𝐋}(0,1),), 𝐋, nothing}}
     @test 3mm != 3*(m*m)                        # mm not interpreted as m*m
     @test (3+4im)*V === V*(3+4im) === (3V+4V*im)  # Complex quantity construction
+    @test !isreal(Base.complex(3.0/m, 4.0/m))
+    @test !isreal(Base.complex((3.0+4.0im)/m))
+    @test Base.reim(Base.complex((3.0+4.0im)/m)) == (3.0/m, 4.0/m)
+    @test Base.widen(Base.complex(Float32(3.0)/m)) == Base.complex(Float64(3.0)/m)
     @test 3*NoUnits === 3
     @test 3*(FreeUnits(m)/FreeUnits(m)) === 3
     @test 3*(ContextUnits(m)/ContextUnits(m)) === 3
@@ -69,6 +73,11 @@ const colon = Base.:(:)
     @test_throws DimensionError ContextUnits(m,kg)
 end
 
+@testset "Types" begin
+    @test Base.complex(Quantity{Float64,NoDims,NoUnits}) ==
+        Quantity{Complex{Float64},NoDims,NoUnits}
+end
+
 @testset "Conversion" begin
     @testset "> Unitless ↔ unitful conversion" begin
         @test_throws DimensionError convert(typeof(3m), 1)