Add {copy,flip}sign(::Number, ::AbstractQuantity) (#612)

Author: sostock

src/quantities.jl

@@ -256,7 +256,12 @@ abs2(x::AbstractQuantity) = Quantity(abs2(x.val), unit(x)*unit(x))
 angle(x::AbstractQuantity{<:Complex}) = angle(x.val)
 
 copysign(x::AbstractQuantity, y::Number) = Quantity(copysign(x.val,y/unit(y)), unit(x))
+copysign(x::Number, y::AbstractQuantity) = copysign(x,y/unit(y))
+copysign(x::AbstractQuantity, y::AbstractQuantity) = Quantity(copysign(x.val,y/unit(y)), unit(x))
+
 flipsign(x::AbstractQuantity, y::Number) = Quantity(flipsign(x.val,y/unit(y)), unit(x))
+flipsign(x::Number, y::AbstractQuantity) = flipsign(x,y/unit(y))
+flipsign(x::AbstractQuantity, y::AbstractQuantity) = Quantity(flipsign(x.val,y/unit(y)), unit(x))
 
 for (i,j) in zip((:<, :isless), (:_lt, :_isless))
     @eval ($i)(x::AbstractQuantity, y::AbstractQuantity) = ($j)(x,y)

test/runtests.jl

@@ -1076,8 +1076,19 @@ end
     @test @inferred(signbit(-0.0m)) == true
     @test @inferred(copysign(3.0m, -4.0s)) == -3.0m
     @test @inferred(copysign(3.0m, 4)) == 3.0m
+    @test @inferred(copysign(3, -4.0m)) == -3
     @test @inferred(flipsign(3.0m, -4)) == -3.0m
     @test @inferred(flipsign(-3.0m, -4)) == 3.0m
+    @test @inferred(flipsign(-3.0, -4m)) == 3.0
+    @test @inferred(flipsign(-3, 4.0m)) == -3
+    @test @inferred(flipsign(3.0m, -4s)) == -3.0m
+    @test @inferred(flipsign(-3m, 4.0s)) == -3m
+    @test @inferred(flipsign((3.0+4.0im)m, -4)) == (-3.0-4.0im)m
+    @test @inferred(flipsign((-3.0+4.0im)m, -4)) == (3.0-4.0im)m
+    @test @inferred(flipsign(-3+4im, -4m)) == 3-4im
+    @test @inferred(flipsign(-3.0+4.0im, 4m)) == -3.0+4.0im
+    @test @inferred(flipsign((3.0+4.0im)m, -4s)) == (-3.0-4.0im)m
+    @test @inferred(flipsign((-3+4im)m, 4.0s)) == (-3+4im)m
     @test @inferred(real(3m)) == 3.0m
     @test @inferred(real((3+4im)V)) == 3V
     @test @inferred(imag(3m)) == 0m