Define == and isapprox for transforms (#14)

* Define '==' and 'isapprox' for transforms

* Update CI.yml

---------

Co-authored-by: Júlio Hoffimann <[email protected]>

.github/workflows/CI.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.6'
+          - '1.9'
           - '1'
         os:
           - ubuntu-latest

src/interface.jl

@@ -123,6 +123,19 @@ reapply(transform::Transform, object, cache) = apply(transform, object) |> first
 
 (transform::Transform)(object) = apply(transform, object) |> first
 
+Base.:(==)(t₁::Transform, t₂::Transform) = nameof(typeof(t₁)) == nameof(typeof(t₂)) && parameters(t₁) == parameters(t₂)
+
+Base.isapprox(t₁::Transform, t₂::Transform; kwargs...) =
+  nameof(typeof(t₁)) == nameof(typeof(t₂)) && _isapprox(parameters(t₁), parameters(t₂); kwargs...)
+
+_isapprox(tup₁::NamedTuple, tup₂::NamedTuple; kwargs...) =
+  propertynames(tup₁) == propertynames(tup₂) && _isapprox(Tuple(tup₁), Tuple(tup₂); kwargs...)
+
+_isapprox(tup₁::Tuple, tup₂::Tuple; kwargs...) =
+  length(tup₁) == length(tup₂) && all(_isapprox(x₁, x₂; kwargs...) for (x₁, x₂) in zip(tup₁, tup₂))
+
+_isapprox(x₁, x₂; kwargs...) = isapprox(x₁, x₂; kwargs...)
+
 # -----------
 # IO METHODS
 # -----------

test/runtests.jl

@@ -48,6 +48,20 @@ using Test
   @test T[begin] == TestTransform()
   @test T[end] == Identity()
 
+  # equality and approximation
+  struct TestParamTransform <: TransformsBase.Transform
+    param::Float64
+  end
+  TransformsBase.apply(t::TestParamTransform, x) = x * t.param, nothing
+  TransformsBase.parameters(t::TestParamTransform) = (; param=t.param)
+  T1 = TestParamTransform(1.0)
+  T2 = TestParamTransform(1.0f0)
+  T3 = TestTransform()
+  @test T1 == T2
+  @test T1 ≠ T3
+  @test T1 ≈ T2
+  @test T1 ≉ T3
+
   T1 = Identity()
   T2 = TestTransform()
   T3 = TestTransform() → TestTransform()