From 5307205b51c735ef0dfda81ced0e6917b03a13bd Mon Sep 17 00:00:00 2001
From: Twan Koolen <koolen.twan@gmail.com>
Date: Sun, 6 Nov 2016 16:31:56 -0500
Subject: [PATCH] Add ability to create an anonymous frame.

---
 src/frames.jl       | 5 ++++-
 test/test_frames.jl | 7 +++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/frames.jl b/src/frames.jl
index bb812146..7803f713 100644
--- a/src/frames.jl
+++ b/src/frames.jl
@@ -11,14 +11,17 @@ const frame_names = Dict{Int64, String}()
 
 immutable CartesianFrame3D
     id::Int64
+
     function CartesianFrame3D(name::String)
         ret = new(next_frame_id.x)
         next_frame_id.x += 1
         frame_names[ret.id] = name
         ret
     end
+
+    CartesianFrame3D() = new(-1)
 end
-name(frame::CartesianFrame3D) = frame_names[frame.id]
+name(frame::CartesianFrame3D) = frame.id >= 0 ? frame_names[frame.id] : "(anonymous)"
 show(io::IO, frame::CartesianFrame3D) = print(io, "CartesianFrame3D: \"$(name(frame))\"")
 
 # enable/disable frame checks
diff --git a/test/test_frames.jl b/test/test_frames.jl
index 48c834ea..7e5c4a38 100644
--- a/test/test_frames.jl
+++ b/test/test_frames.jl
@@ -1,6 +1,9 @@
 @testset "frames" begin
-    f1 = CartesianFrame3D("1")
-    f2 = CartesianFrame3D("2")
+    f1name = "1"
+    f1 = CartesianFrame3D(f1name)
+    f2 = CartesianFrame3D() # anonymous
+    @test name(f1) == f1name
+    name(f2) # just to make sure it doesn't crash
 
     t1 = rand(Transform3D{Float64}, f2, f1)
     @test isapprox(t1 * inv(t1), Transform3D{Float64}(f1))