composing

Author: rafaqz

src/optics.jl

@@ -133,8 +133,6 @@ struct ConstructIfChanged{C}
     constructor::C
 end
 
-_constructor(x, t) = _constructor(x.handler, t)
-
 # TODO what do we call these things?
 struct Construct end
 _constructor(::Construct, ::Type{T}) where T = constructorof(T)
@@ -251,19 +249,6 @@ function modify(f, obj, w::If)
     end
 end
 
-struct Select{C}
-    select_condition::C
-end
-OpticStyle(::Type{<:If}) = ModifyBased()
-
-function modify(f, obj, w::If)
-    if w.modify_condition(obj)
-        (obj,)
-    else
-        ()
-    end
-end
-
 """
     mapproperties(f, obj)
 
@@ -280,7 +265,7 @@ julia> Accessors.mapproperties(x -> x+1, obj)
 ```
 $EXPERIMENTAL
 """
-function mapproperties(f, obj::O, optic, itr::Nothing=nothing) where O
+function mapproperties(f, obj::O, handler=Construct(), itr::Nothing=nothing) where O
     # TODO move this helper elsewhere?
     pnames = propertynames(obj)
     if isempty(pnames)
@@ -290,11 +275,11 @@ function mapproperties(f, obj::O, optic, itr::Nothing=nothing) where O
         new_props = map(pnames) do p
             f(getproperty(obj, p))
         end
-        ctr = _constructor(optic, O)
+        ctr = _constructor(handler, O)
         return ctr(new_props...)
     end
 end
-function mapproperties(f, obj::O, optic, itr::Int) where O
+function mapproperties(f, obj::O, handler, itr::Int) where O
     pnames = propertynames(obj)
     if isempty(pnames)
         return _maybeitr(obj, itr)
@@ -304,7 +289,7 @@ function mapproperties(f, obj::O, optic, itr::Int) where O
             val, itr = f(getproperty(obj, p), itr)
             (vals..., val), itr
         end
-        ctr = _constructor(optic, O)
+        ctr = _constructor(handler, O)
         return _maybeitr(ctr(new_props...), itr)
     end
 end
@@ -330,10 +315,7 @@ Based on [`mapproperties`](@ref).
 
 $EXPERIMENTAL
 """
-struct Properties{H}
-    handler::H
-end
-Properties() = Properties(Construct())
+struct Properties end
 OpticStyle(::Type{<:Properties}) = ModifyBased()
 modify(f, o, ::Properties) = mapproperties(f, o)
 
@@ -353,7 +335,7 @@ julia> Accessors.mapfields(x -> x+1, obj)
 ```
 $EXPERIMENTAL
 """
-@generated function mapfields(f, obj::O, optic, itr::I=nothing) where {O,H,I}
+@generated function mapfields(f, obj::O, handler::H=Construct(), itr::I=nothing) where {O,H,I}
     # TODO: This is how Flatten.jl works, but it's not really 
     # correct use of ConstructionBase as it assumers properties=fields
     fnames = fieldnames(O)
@@ -424,12 +406,9 @@ Based on [`mapfields`](@ref).
 
 $EXPERIMENTAL
 """
-struct Fields{H} 
-    handler::H
-end
-Fields() = Fields(Construct())
+struct Fields end
 OpticStyle(::Type{<:Fields}) = ModifyBased()
-modify(f, o, optic::Fields) = mapfields(f, o, optic)
+modify(f, o, ::Fields) = mapfields(f, o)
 
 """
     Recursive(descent_condition, optic)
@@ -528,18 +507,22 @@ julia> modify(x -> 100x, obj, Recursive(x -> (x isa Tuple), Elements()))
 ```
 $EXPERIMENTAL
 """
-struct Query{Select,Descend,Optic}
+struct Query{Select,Descend,Optic<:Union{ComposedOptic,Fields,Properties}}
     select_condition::Select
     descent_condition::Descend
     optic::Optic
 end
 Query(select, descend = x -> true) = Query(select, descend, Fields())
 Query(; select=Any, descend=x -> true, optic=Fields()) = Query(select, descend, optic)
 
+_inner(optic::ComposedOptic) = optic.inner
+_inner(optic::Fields) = optic
+_inner(optic::Properties) = optic
+
 function (q::Query)(obj)
-    _query(obj, q.optic, Splat(), nothing) do o
+    _query(obj, _inner(q.optic), Splat(), nothing) do o
         if q.select_condition(o)
-            (o,)
+            (_getouter(o, q.optic),)
         elseif q.descent_condition(o)
             q(o)
         else
@@ -548,12 +531,15 @@ function (q::Query)(obj)
     end
 end
 
+_getouter(o, optic::ComposedOptic) = optic.outer(o)
+_getouter(o, optic) = o
+
 _set(obj, q::Query, val, ::SetBased) = _setquery(obj, q::Query, (val, 1))[1]
 
 function _setquery(obj, q::Query, (val, itr))
-    _query(obj, q.optic, Construct(), itr) do o, itr
+    _query(obj, _inner(q.optic), Construct(), itr) do o, itr
         if q.select_condition(o)
-            val[itr], itr + 1
+            _setouter(o, q.optic, val[itr]), itr + 1
         elseif q.descent_condition(o)
             _setquery(o, q, (val, itr))
         else
@@ -562,8 +548,10 @@ function _setquery(obj, q::Query, (val, itr))
     end
 end
 
+_setouter(o, optic::ComposedOptic, v) = set(o, optic.outer, v)
+_setouter(o, optic, v) = v
+
 modify(f, obj, q::Query) = set(obj, q, map(f, q(obj)))
 
-_query(f, o, ::Elements, itr) = map(f, o)
-_query(f, o, ::Fields, itr) = mapfields(f, o, itr)
-_query(f, o, ::Properties, itr) = mapproperties(f, o, itr)
+_query(f, o, ::Fields, handler, itr) = mapfields(f, o, handler, itr)
+_query(f, o, ::Properties, handler, itr) = mapproperties(f, o, handler, itr)

test/test_queries.jl

@@ -1,11 +1,19 @@
 using Accessors, Test, BenchmarkTools
 
-obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), (x=6.0,), [1])
+obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), ((a=6.0,), [1]))
 vals = (1.0, 2.0, 3.0, 4.0)
 
 # Fields is the default
-lens = Query(; select=x -> x isa Float64, descend=x -> x isa NamedTuple)
-slowlens = Query(x -> x isa Float64, x -> x isa NamedTuple, Accessors.Properties())
+lens = Query(; 
+    select=x -> x isa NamedTuple, 
+    descend=x -> x isa Tuple, 
+    optic = (Accessors.@optic _.a) ∘ Accessors.Fields()
+)
+slowlens = Query(; 
+    select=x -> x isa NamedTuple, 
+    descend=x -> x isa Tuple, 
+    optic = (Accessors.@optic _.a) ∘ Accessors.Properties()
+)
 
 @code_typed lens(obj)
 @code_typed slowlens(obj)
@@ -22,12 +30,13 @@ println("set")
 # Need a wrapper so we don't have to pass in the starting iterator
 @btime Accessors.set($obj, $lens, $vals)
 @btime Accessors.set($obj, $slowlens, $vals)
+Accessors.set(obj, lens, vals) 
 @test Accessors.set(obj, lens, vals) == 
     Accessors.set(obj, lens, vals) == 
-    (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), (x=2.0,), [1])
+    (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), ((a=2.0,), [1]))
 
-using ProfileView
-@profview for i in 1:1000000 Accessors.set(obj, lens, vals) end
+# using ProfileView
+# @profview for i in 1:1000000 Accessors.set(obj, lens, vals) end
 
 println("unstable set")
 unstable_lens = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x -> x isa NamedTuple)
@@ -37,12 +46,4 @@ unstable_lens = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x ->
 
 # Somehow modify compiles away almost completely
 @btime modify(x -> 10x, $obj, $lens)
-@test modify(x -> 10x, obj, lens) == (7, (a=170.0, b=2.0f0), ("3", 4, 5.0), (x=60.0,), [1])
-using ProfileView
-@profview for i in 1:1000000 modify(x -> 10x, obj, lens) end
-
-
-obj = (1,2,3,4,5,6);
-
-@macroexpand 
-@set obj |> Properties() |> If(iseven)
+@test modify(x -> 10x, obj, lens) == (7, (a=170.0, b=2.0f0), ("3", 4, 5.0), ((a=60.0,), [1]))