traits only get applied and defined on instances

minor tweaks

fix test

Author: ablaom

docs/src/index.md

@@ -112,8 +112,9 @@ target appears in training (is supervised) or whether the model generalizes to n
 observations (learns) or not. 
 
 The target and the kind of predicted proxy are crucial features of ML/statistics
-performance measures and LearnAPI.jl provides a detailed list of proxy dispatch types (see
-[Target proxies](@ref)), as well as algorithm traits to articulate target type /scitype.
+performance measures (not provided by this package) and LearnAPI.jl provides a detailed
+list of proxy dispatch types (see [Target proxies](@ref)), as well as algorithm traits to
+articulate target type /scitype.
 
 
 ## Optional data interface

src/tools.jl

@@ -21,19 +21,18 @@ macro trait(algorithm_ex, exs...)
 end
 
 """
+    typename(x)
 
-    typename(T::Type)
+Return a symbolic representation of the name of `type(x)`, stripped of any type-parameters
+and module qualifications. For example, if
 
-Return a symbol corresponding to the name of the type `T`, stripped of
-any type-parameters and module qualifications. For example:
+    typeof(x) = MLJBase.Machine{MLJAlgorithms.ConstantRegressor,true}
 
-    _typename(MLJBase.Machine{MLJAlgorithms.ConstantRegressor,true})
-
-returns `:Machine`. Where this does not make sense (eg, instances of
-`Union`) `Symbol(string(M))` is returned.
+Then `typename(x)` returns `:Machine`.
 
 """
-function typename(M)
+function typename(x)
+    M = typeof(x)
     if isdefined(M, :name)
         return M.name.name
     elseif isdefined(M, :body)

test/tools.jl

@@ -19,14 +19,10 @@ import .Fruit
 ## HELPERS
 
 @testset "typename" begin
-    @test LearnAPI.typename(Fruit.RedApple) == :RedApple
-    @test LearnAPI.typename(Fruit.RedApple{Int}) == :RedApple
-    @test LearnAPI.typename(Nothing) == :Nothing
-    @test LearnAPI.typename(UnionAll) == :UnionAll
-    @test LearnAPI.typename(Union{Char,Int}) ==
-        Symbol("Union{Char, Int64}")
-    T = SparseArrays.sparse([1,2], [1,3], [0.5, 0.6]) |> typeof
-    @test LearnAPI.typename(T) == :SparseMatrixCSC
+    @test LearnAPI.typename(Fruit.RedApple(1)) == :RedApple
+    @test LearnAPI.typename(nothing) == :Nothing
+    m = SparseArrays.sparse([1,2], [1,3], [0.5, 0.6])
+    @test LearnAPI.typename(m) == :SparseMatrixCSC
 end
 
 @testset "snakecase" begin