deg2rad and rad2deg with "units" (#459)

* deg2rad and rad2deg

* v1.9

* Update src/pkgdefaults.jl

Co-authored-by: Mosè Giordano <giordano@users.noreply.github.com>

Co-authored-by: Mosè Giordano <giordano@users.noreply.github.com>

Author: JeffFessler

Project.toml

@@ -1,6 +1,6 @@
 name = "Unitful"
 uuid = "1986cc42-f94f-5a68-af5c-568840ba703d"
-version = "1.8.0"
+version = "1.9.0"
 
 [deps]
 ConstructionBase = "187b0558-2788-49d3-abe0-74a17ed4e7c9"

src/pkgdefaults.jl

@@ -73,6 +73,11 @@ for (_x,_y) in ((:sin,:sind), (:cos,:cosd), (:tan,:tand),
     @eval ($_y)(x::Quantity{T, NoDims, typeof(°)}) where {T} = ($_y)(ustrip(x))
 end
 
+# conversion between degrees and radians
+import Base: deg2rad, rad2deg
+deg2rad(d::Quantity{T, NoDims, typeof(°)}) where {T} = deg2rad(ustrip(°, d))u"rad"
+rad2deg(r::Quantity{T, NoDims, typeof(rad)}) where {T} = rad2deg(ustrip(rad, r))u"°"
+
 # SI and related units
 @unit Hz              "Hz"   Hertz           1/s                true
 @unit N               "N"    Newton          1kg*m/s^2          true

test/runtests.jl

@@ -193,6 +193,10 @@ end
             @test 1u"rps" == 2π/s
             @test 1u"rpm" == 360°/minute
             @test 1u"rpm" == 2π/minute
+
+            # Issue 458:
+            @test deg2rad(360°) ≈ 2π * rad
+            @test rad2deg(2π * rad) ≈ 360°
         end
     end
 end