From 2945d61f4fd10071e3b33a44b92d4761466a8ad6 Mon Sep 17 00:00:00 2001
From: Mark Kittisopikul <markkitt@gmail.com>
Date: Sun, 25 Dec 2022 06:52:18 -0500
Subject: [PATCH] Add virtual properties for values and indices

---
 src/axes.jl      | 32 ++++++++++++++++++++++++++++++++
 test/runtests.jl | 15 +++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/src/axes.jl b/src/axes.jl
index 519f0dac..a230e918 100644
--- a/src/axes.jl
+++ b/src/axes.jl
@@ -40,6 +40,27 @@ julia> ro[3]
 ERROR: BoundsError: attempt to access 3-element $(IdOffsetRange{Int, UnitRange{Int}}) with indices -1:1 at index [3]
 ```
 
+The `values` and `indices` keywords can be extracted as properties or via the `values` and `eachindex` methods.
+```jldoctest ior
+julia> values(ro)
+IdOffsetRange(values=9:11, indices=-1:1)
+
+julia> ro.values
+IdOffsetRange(values=9:11, indices=-1:1)
+
+julia> UnitRange(ro.values)
+9:11
+
+julia> eachindex(ro)
+IdOffsetRange(values=-1:1, indices=-1:1)
+
+julia> ro.indices
+IdOffsetRange(values=-1:1, indices=-1:1)
+
+julia> ro.indices |> UnitRange
+-1:1
+```
+
 # Extended help
 
 Construction/coercion preserves the (shifted) values of the input range, but may modify
@@ -277,6 +298,17 @@ Broadcast.broadcasted(::Base.Broadcast.DefaultArrayStyle{1}, ::typeof(big), r::I
 
 Base.show(io::IO, r::IdOffsetRange) = print(io, IdOffsetRange, "(values=",first(r), ':', last(r),", indices=",first(eachindex(r)),':',last(eachindex(r)), ")")
 
+
+# Based on the constructor display above, allow for the keywords to be extracted as
+# properties. The properties will be `IdOffsetRange` rather than `UnitRange`
+@inline Base.getproperty(r::IdOffsetRange, s::Symbol) =
+    s == :values ? values(r) :
+    s == :indices ? eachindex(r) :
+    getfield(r, s)
+
+@inline Base.propertynames(r::IdOffsetRange) =
+    (fieldnames(typeof(r))..., :values, :indices)
+
 # Optimizations
 @inline Base.checkindex(::Type{Bool}, inds::IdOffsetRange, i::Real) = Base.checkindex(Bool, inds.parent, i - inds.offset)
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 7cd56bfb..7e10077e 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -203,6 +203,7 @@ end
             for i in eachindex(s)
                 @test r[s[i]] == r[s][i]
             end
+            @test eachindex(s) === s.indices
 
             # Indexing with UnitRange
             s = 0:2
@@ -401,6 +402,20 @@ end
         ind, st = iterate(ax, st)
         @test C[ind] == C[5]
     end
+
+    @testset "virtual properties" begin
+        _values = 5:8
+        _indices = 6:9
+        id = IdOffsetRange(values=_values, indices=_indices)
+        @test id.values === values(id)
+        @test id.values == _values
+        @test id.indices === eachindex(id)
+        @test id.indices == _indices
+        id2 = IdOffsetRange(; id.values, id.indices)
+        @test id == id2
+        id3 = IdOffsetRange(; id.indices, id.values)
+        @test id == id3
+    end
 end
 
 # used in testing the constructor