Refactor the Transforms show (#7)

Author: eliascarv

src/TransformsBase.jl

@@ -6,6 +6,7 @@ module TransformsBase
 
 import AbstractTrees
 
+include("ioutils.jl")
 include("interface.jl")
 include("sequential.jl")
 include("identity.jl")

src/interface.jl

@@ -123,22 +123,21 @@ reapply(transform::Transform, object, cache) = apply(transform, object) |> first
 
 (transform::Transform)(object) = apply(transform, object) |> first
 
+# -----------
+# IO METHODS
+# -----------
+
+Base.summary(io::IO, transform::Transform) = print(io, "$(prettyname(transform)) transform")
+
 function Base.show(io::IO, transform::Transform)
-  T = typeof(transform)
-  vals = getfield.(Ref(transform), fieldnames(T))
-  strs = repr.(vals, context=io)
-  print(io, "$(nameof(T))($(join(strs, ", ")))")
+  name = prettyname(transform)
+  ioctx = IOContext(io, :compact => true)
+  print(io, "$name(")
+  printfields(ioctx, transform, singleline=true)
+  print(io, ")")
 end
 
 function Base.show(io::IO, ::MIME"text/plain", transform::Transform)
-  T = typeof(transform)
-  fnames = fieldnames(T)
-  len = length(fnames)
-  print(io, "$(nameof(T)) transform")
-  for (i, field) in enumerate(fnames)
-    div = i == len ? "\n└─ " : "\n├─ "
-    val = getfield(transform, field)
-    str = repr(val, context=io)
-    print(io, "$div$field = $str")
-  end
+  summary(io, transform)
+  printfields(io, transform)
 end

src/ioutils.jl

@@ -0,0 +1,31 @@
+# ------------------------------------------------------------------
+# Licensed under the MIT License. See LICENSE in the project root.
+# ------------------------------------------------------------------
+
+prettyname(obj) = prettyname(typeof(obj))
+function prettyname(T::Type)
+  name = string(T)
+  name = replace(name, r"{.*" => "")
+  replace(name, r".*\." => "")
+end
+
+printfields(io, obj; kwargs...) = printfields(io, obj, fieldnames(typeof(obj)); kwargs...)
+
+function printfields(io, obj, fnames; singleline=false)
+  if singleline
+    vals = map(enumerate(fnames)) do (i, field)
+      val = getfield(obj, i)
+      str = repr(val, context=io)
+      "$field: $str"
+    end
+    join(io, vals, ", ")
+  else
+    len = length(fnames)
+    for (i, field) in enumerate(fnames)
+      div = i == len ? "\n└─ " : "\n├─ "
+      val = getfield(obj, i)
+      str = repr(val, context=io)
+      print(io, "$div$field: $str")
+    end
+  end
+end

test/runtests.jl

@@ -43,4 +43,17 @@ using Test
   @test lastindex(T) == 2
   @test T[begin] == TestTransform()
   @test T[end] == Identity()
+
+  T1 = Identity()
+  T2 = TestTransform()
+  T3 = TestTransform() → TestTransform()
+  @test sprint(show, T1) == "Identity()"
+  @test sprint(show, MIME("text/plain"), T1) == "Identity transform"
+  @test sprint(show, T2) == "TestTransform()"
+  @test sprint(show, MIME("text/plain"), T2) == "TestTransform transform"
+  @test sprint(show, T3) == "TestTransform() → TestTransform()"
+  @test sprint(show, MIME("text/plain"), T3) == """
+  SequentialTransform
+  ├─ TestTransform()
+  └─ TestTransform()"""
 end