From 624cd376d50c821dd2446cbee1aed32501d8ced3 Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Sun, 6 Jun 2021 14:39:37 +1000
Subject: [PATCH 01/10] get/set queries

---
 src/optics.jl        | 174 +++++++++++++++++++++++++++++++++++--------
 src/sugar.jl         |  72 +++++++++++++++++-
 test/test_optics.jl  |   2 +
 test/test_queries.jl | 104 ++++++++++++++++++++++++++
 4 files changed, 321 insertions(+), 31 deletions(-)
 create mode 100644 test/test_queries.jl

diff --git a/src/optics.jl b/src/optics.jl
index 9d532096..5179a204 100644
--- a/src/optics.jl
+++ b/src/optics.jl
@@ -1,7 +1,7 @@
 export @optic
 export set, modify
 export ∘, opcompose, var"⨟"
-export Elements, Recursive, If, Properties
+export Elements, Recursive, Query, If, Properties
 export setproperties
 export constructorof
 using ConstructionBase
@@ -125,6 +125,7 @@ function _set(obj, optic, val, ::SetBased)
    )
 end
 
+<<<<<<< HEAD
 if VERSION < v"1.7"
     struct Returns{V}
         value::V
@@ -132,6 +133,32 @@ if VERSION < v"1.7"
     (o::Returns)(x) = o.value
 else
     using Base: Returns
+=======
+
+struct Changed end
+struct Unchanged end
+
+struct MaybeConstruct end
+_constructor(::MaybeConstruct, ::Type{T}) where T = constructorof(T)
+
+struct List end
+_constructor(::List, ::Type) = tuple
+
+struct Splat end
+_constructor(::Splat, ::Type) = _splat_all
+
+_splat_all(args...) = _splat_all(args)  
+@generated function _splat_all(args::A) where A<:Tuple  
+    exp = Expr(:tuple)
+    for i in fieldnames(A)
+        push!(exp.args, Expr(:..., :(args[$i])))
+    end
+    exp
+end
+
+
+struct Constant{V}
+    value::V
 end
 
 @inline function _set(obj, optic, val, ::ModifyBased)
@@ -189,9 +216,7 @@ $EXPERIMENTAL
 struct Elements end
 OpticStyle(::Type{<:Elements}) = ModifyBased()
 
-function modify(f, obj, ::Elements)
-    map(f, obj)
-end
+modify(f, obj, ::Elements) = map(f, obj)
 
 """
     If(modify_condition)
@@ -222,8 +247,36 @@ function modify(f, obj, w::If)
     end
 end
 
+abstract type ObjectMap end
+
+OpticStyle(::Type{<:ObjectMap}) = ModifyBased()
+modify(f, o, optic::ObjectMap) = mapobject(f, o, optic, Construct)
+
 """
-    mapproperties(f, obj)
+    Properties()
+
+Access all properties of an objects.
+
+```jldoctest
+julia> using Accessors
+
+julia> obj = (a=1, b=2, c=3)
+(a = 1, b = 2, c = 3)
+
+julia> set(obj, Properties(), "hi")
+(a = "hi", b = "hi", c = "hi")
+
+julia> modify(x -> 2x, obj, Properties())
+(a = 2, b = 4, c = 6)
+```
+Based on [`mapobject`](@ref).
+
+$EXPERIMENTAL
+"""
+struct Properties <: ObjectMap end
+
+"""
+    mapobject(f, obj)
 
 Construct a copy of `obj`, with each property replaced by
 the result of applying `f` to it.
@@ -233,7 +286,7 @@ julia> using Accessors
 
 julia> obj = (a=1, b=2);
 
-julia> Accessors.mapproperties(x -> x+1, obj)
+julia> Accessors.mapobject(x -> x+1, obj)
 (a = 2, b = 3)
 ```
 
@@ -257,30 +310,19 @@ function mapproperties(f, obj)
     return setproperties(obj, patch)
 end
 
-"""
-    Properties()
-
-Access all properties of an objects.
-
-```jldoctest
-julia> using Accessors
-
-julia> obj = (a=1, b=2, c=3)
-(a = 1, b = 2, c = 3)
-
-julia> set(obj, Properties(), "hi")
-(a = "hi", b = "hi", c = "hi")
-
-julia> modify(x -> 2x, obj, Properties())
-(a = 2, b = 4, c = 6)
-```
-Based on [`mapproperties`](@ref).
+# Don't construct when we don't absolutely have to.
+# `constructorof` may not be defined for an object.
+@generated function _maybeconstruct(obj::O, props::P, handler::H) where {O,P,H}
+    ctr = _constructor(H(), O)
+    if Changed in map(last ∘ fieldtypes, fieldtypes(P))
+        :($ctr(map(first, props)...) => Changed())
+    else
+        :(obj => Unchanged())
+    end
+end
 
-$EXPERIMENTAL
-"""
-struct Properties end
-OpticStyle(::Type{<:Properties}) = ModifyBased()
-modify(f, o, ::Properties) = mapproperties(f, o)
+skip(::Splat) = true
+skip(x) = false
 
 """
     Recursive(descent_condition, optic)
@@ -318,6 +360,80 @@ function _modify(f, obj, r::Recursive, ::ModifyBased)
     end
 end
 
+abstract type AbstractQuery end
+
+"""
+    Query(select, descend, optic)
+
+Query an object recursively, choosing fields when `select` 
+returns `true`, and descending when `descend`.
+
+```jldoctest
+julia> using Accessors
+
+julia> obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
+(a = missing, b = 1, c = (d = missing, e = (f = missing, g = 2)))
+
+julia> set(obj, Query(ismissing), (1.0, 2.0, 3.0))
+(a = 1.0, b = 1, c = (d = 2.0, e = (f = 3.jjjjjjtk,rg, g = 2)))
+
+julia> obj = (1,2,(3,(4,5),6))
+(1, 2, (3, (4, 5), 6))
+
+julia> modify(x -> 100x, obj, Recursive(x -> (x isa Tuple), Elements()))
+(100, 200, (300, (400, 500), 600))
+```
+$EXPERIMENTAL
+"""
+struct Query{Select,Descend,Optic<:Union{ComposedOptic,Properties}} <: AbstractQuery
+    select_condition::Select
+    descent_condition::Descend
+    optic::Optic
+end
+Query(select, descend = x -> true) = Query(select, descend, Properties())
+Query(; select=Any, descend=x -> true, optic=Properties()) = Query(select, descend, optic)
+
+OpticStyle(::Type{<:AbstractQuery}) = SetBased()
+
+@inline function (q::AbstractQuery)(obj)
+    let obj=obj, q=q
+        mapobject(obj, _inner(q.optic), Splat()) do o
+            if q.select_condition(o)
+                (_getouter(o, q.optic),)
+            elseif q.descent_condition(o)
+                q(o) # also a tuple
+            else
+                ()
+            end
+        end
+    end
+end
+
+set(obj, q::AbstractQuery, vals) = _set(obj, q, (vals, 1))[1][1]
+
+@inline function _set(obj, q::AbstractQuery, (vals, itr))
+    let obj=obj, q=q, vals=vals, itr=itr
+        mapobject(obj, _inner(q.optic), MaybeConstruct(), itr) do o, itr::Int
+            if q.select_condition(o)
+                _setouter(o, q.optic, vals[itr]) => Changed(), itr + 1
+            elseif q.descent_condition(o)
+                _set(o, q, (vals, itr)) # Will be marked as Changed()/Unchanged()
+            else
+                o => Unchanged(), itr 
+            end
+        end
+    end
+end
+
+modify(f, obj, q::Query) = set(obj, q, map(f, q(obj)))
+
+@inline _inner(optic::ComposedOptic) = optic.inner
+@inline _inner(optic) = optic
+@inline _getouter(o, optic::ComposedOptic) = optic.outer(o)
+@inline _getouter(o, optic) = o
+@inline _setouter(o, optic::ComposedOptic, v) = set(o, optic.outer, v)
+@inline _setouter(o, optic, v) = v
+
 ################################################################################
 ##### Lenses
 ################################################################################
diff --git a/src/sugar.jl b/src/sugar.jl
index 3d5494dd..c7aefd87 100644
--- a/src/sugar.jl
+++ b/src/sugar.jl
@@ -1,4 +1,4 @@
-export @set, @optic, @reset, @modify
+export @set, @optic, @reset, @modify, @getall, @setall
 using MacroTools
 
 """
@@ -84,13 +84,81 @@ end
 This function can be used to create a customized variant of [`@modify`](@ref).
 See also [`opticmacro`](@ref), [`setmacro`](@ref).
 """
-
 function modifymacro(optictransform, f, obj_optic)
     f = esc(f)
     obj, optic = parse_obj_optic(obj_optic)
     :(($modify)($f, $obj, $(optictransform)($optic)))
 end
 
+"""
+    @getall f(obj, arg...)
+    @setall [x for x in obs if x isa Number] = values
+
+@getall obj isa Number
+"""
+macro getall(ex)
+    getallmacro(ex)
+end
+macro getall(ex, descend)
+    getallmacro(ex; descend)
+end
+
+function getallmacro(ex; descend=true)
+    # Wrap descend in an anonoymous function
+    descend = :(descend -> $descend)
+    if @capture(ex, (lens_ for var_ in obj_ if select_))
+        select = _select(select, var)
+        optic =_optics(lens)
+        :(Query($select, $descend, $optic)($(esc(obj))))
+    elseif @capture(ex, [lens_ for var_ in obj_ if select_])
+        select = _select(select, var)
+        optic =_optics(lens)
+        :([Query($select, $descend, $optic)($(esc(obj)))...])
+    elseif @capture(ex, (lens_ for var_ in obj_))
+        select = _ -> false
+        optic = _optics(lens)
+        :(Query($select, $descend, $optic)($(esc(obj))))
+    elseif @capture(ex, [lens_ for var_ in obj_])
+        select = _ -> false
+        optic = _optics(lens)
+        :([Query($select, $descend, $optic)($(esc(obj)))...])
+    else 
+        error("@getall must be passed a generator")
+    end
+end
+
+# Turn this into an anonoymous function so it
+# doesn't matter which argument val is in
+_select(select, val) = :($(esc(val)) -> $(esc(select)))
+function _optics(ex)
+    obj, optic = parse_obj_optic(ex)
+    :($optic ∘ Fields())
+end
+
+
+"""
+    @setall f(obj, arg...) = values
+    
+    @setall [x for x in obs if x isa Number] = values
+
+"""
+macro setall(ex)
+    setallmacro(ex)
+end
+
+function setallmacro(ex)
+    if @capture(ex, ((lens_ for var_ in obj_ if select_) = vals_))
+        select = _select(select, var)
+        optic =_optics(lens)
+        :(set($(esc(obj)), Query(; select=$select, optic=$optic), $(esc(vals))))
+    elseif @capture(ex, ((lens_ for var_ in obj_) = vals_))
+        optic = _optics(lens)
+        :(set($(esc(obj)), Query(; optic=$optic), $(esc(vals))))
+    else 
+        error("@getall must be passed a generator")
+    end
+end
+
 foldtree(op, init, x) = op(init, x)
 foldtree(op, init, ex::Expr) =
     op(foldl((acc, x) -> foldtree(op, acc, x), ex.args; init=init), ex)
diff --git a/test/test_optics.jl b/test/test_optics.jl
index 9d90ddc4..e0b2b1ae 100644
--- a/test/test_optics.jl
+++ b/test/test_optics.jl
@@ -43,6 +43,8 @@ end
     pt = Point(1f0, 2e0, 3)
     pt2 = @inferred modify(x->2x, pt, Properties())
     @test pt2 === Point(2f0, 4e0, 6)
+    @test (x=0, y=1, z=2) === 
+    @set pt |> Properties(pt) -= 1
 end
 
 @testset "Elements" begin
diff --git a/test/test_queries.jl b/test/test_queries.jl
new file mode 100644
index 00000000..59ac4a99
--- /dev/null
+++ b/test/test_queries.jl
@@ -0,0 +1,104 @@
+using Accessors, Test, BenchmarkTools, Static
+
+obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=6.0,), [1,]))
+vals = (1.0, 2.0, 3.0, 4.0)
+
+
+# Fields is the default
+q = Query(; 
+    select=x -> x isa NamedTuple, 
+    descend=x -> x isa Tuple, 
+    optic = (Accessors.@optic _.a) ∘ Accessors.Fields()
+    # optic = Accessors.Fields()
+)
+slowq = Query(; 
+    select=x -> x isa NamedTuple, 
+    descend=x -> x isa Tuple, 
+    optic = (Accessors.@optic _.a) ∘ Accessors.Properties()
+)
+
+q(obj)
+@code_native q(obj)
+@code_native slowq(obj)
+
+@code_warntype q(obj)
+@code_warntype slowq(obj)
+
+
+println("get")
+@benchmark $q($obj)
+@benchmark $slowlens($obj)
+@test q(obj) == slowq(obj) == (17.0, 6.0)
+
+missings_obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
+@test Query(ismissing)(missings_obj) === (missing, missing, missing)
+@benchmark Query(ismissing)($missings_obj)
+
+println("set")
+# Need a wrapper so we don't have to pass in the starting iterator
+set(obj, q, vals) 
+@benchmark set($obj, $q, $vals)
+
+# Package deinition
+# set(obj, q::Query, vals) = _set(obj, q, (vals, 1))[1][1]
+# REPL definition
+f(obj, q::Query, vals) = Accessors._set(obj, q, (vals, 1))[1][1]
+
+julia> @btime f(obj, q, vals)
+  19.302 ns (1 allocation: 80 bytes)
+(7, (a = 1.0, b = 2.0f0), ("3", 4, 5.0), ((x = 19, a = 2.0), [1]))
+
+julia> @btime set(obj, q, vals)
+  89.260 ns (6 allocations: 464 bytes)
+(7, (a = 1.0, b = 2.0f0), ("3", 4, 5.0), ((x = 19, a = 2.0), [1]))
+
+@eval Accessors begin
+    set(obj, q::Query, vals) = _set(obj, q, (vals, 1))[1][1]
+end
+
+@btime f(obj, q, vals)
+@btime set(obj, q, vals) 
+
+# @btime Accessors.set($obj, $slowlens, $vals)
+@test Accessors.set(obj, lens, vals) == 
+    (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=2.0,), [1]))
+
+@code_warntype set(obj, lens, vals) 
+@code_native set(obj, lens, vals) 
+@code_native Accessors._set(obj, lens, (vals, 1))[1]
+
+# using Cthulhu
+# using ProfileView
+# @profview  for i in 1:1000000 Accessors.set(obj, lens, vals) end
+# @descend Accessors.set(obj, lens, vals) 
+
+println("unstable set")
+unstable_lens = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x -> x isa NamedTuple)
+@btime set($obj, $unstable_lens, $vals)
+# slow_unstable_lens = Accessors.Query(; select=x -> x isa Number && x > 4, optic=Properties())
+# @btime Accessors.set($obj, $slow_unstable_lens, $vals))
+
+# Somehow modify compiles away almost completely
+@btime modify(x -> 10x, $obj, $lens)
+
+# Macros
+@test (@getall missings_obj isa Number) == (1, 2)
+expected = (a=missing, b=5, c=(d=missing, e=(f=missing, g=6)))
+@test (@setall missings_obj isa Number = (5, 6)) === expected
+@getall missings_obj isa Number
+@setall missings_obj isa Number = (5, 6)
+
+using Accessors
+
+obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
+
+q = Query(ismissing);
+
+obj2 = set(obj, q, ["first", "wins", "here"])
+
+set(obj2, Query(x -> x isa String), ["second", "should", "win"])
+
+@getall missings_obj isa Number
+missings_obj = (a=missing, b=(1, (; a=4)), c=(d=missing, e=(f=missing, g=2)))
+@setall (x for x in missings_obj if x isa Missing) = (100.0, 200.0, 300.0)
+@getall (x[1] for x in missings_obj if x isa NamedTuple) !(descend isa Dict)

From 44bd20fcab4145f044999e48b5686c1785c2707a Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Wed, 16 Jun 2021 00:40:31 +1000
Subject: [PATCH 02/10] context

---
 src/optics.jl        | 202 +++++++++++++++++++++++++++++++------------
 src/setindex.jl      |   4 +
 src/sugar.jl         |   6 +-
 test/test_queries.jl | 103 +++++++---------------
 4 files changed, 183 insertions(+), 132 deletions(-)

diff --git a/src/optics.jl b/src/optics.jl
index 5179a204..b2bb340a 100644
--- a/src/optics.jl
+++ b/src/optics.jl
@@ -6,6 +6,7 @@ export setproperties
 export constructorof
 using ConstructionBase
 using CompositionsBase
+using Static
 using Base: getproperty
 using Base
 
@@ -125,7 +126,6 @@ function _set(obj, optic, val, ::SetBased)
    )
 end
 
-<<<<<<< HEAD
 if VERSION < v"1.7"
     struct Returns{V}
         value::V
@@ -133,7 +133,8 @@ if VERSION < v"1.7"
     (o::Returns)(x) = o.value
 else
     using Base: Returns
-=======
+end
+
 
 struct Changed end
 struct Unchanged end
@@ -276,19 +277,7 @@ $EXPERIMENTAL
 struct Properties <: ObjectMap end
 
 """
-    mapobject(f, obj)
-
-Construct a copy of `obj`, with each property replaced by
-the result of applying `f` to it.
-
-```jldoctest
-julia> using Accessors
-
-julia> obj = (a=1, b=2);
-
-julia> Accessors.mapobject(x -> x+1, obj)
-(a = 2, b = 3)
-```
+    maproperties()
 
 # Implementation
 
@@ -300,8 +289,8 @@ $EXPERIMENTAL
 """
 function mapproperties end
 
-function mapproperties(f, nt::NamedTuple)
-    map(f,nt)
+function mapproperties(f, nt::Union{Tuple,NamedTuple})
+    map(f, nt)
 end
 
 function mapproperties(f, obj)
@@ -310,17 +299,6 @@ function mapproperties(f, obj)
     return setproperties(obj, patch)
 end
 
-# Don't construct when we don't absolutely have to.
-# `constructorof` may not be defined for an object.
-@generated function _maybeconstruct(obj::O, props::P, handler::H) where {O,P,H}
-    ctr = _constructor(H(), O)
-    if Changed in map(last ∘ fieldtypes, fieldtypes(P))
-        :($ctr(map(first, props)...) => Changed())
-    else
-        :(obj => Unchanged())
-    end
-end
-
 skip(::Splat) = true
 skip(x) = false
 
@@ -360,6 +338,59 @@ function _modify(f, obj, r::Recursive, ::ModifyBased)
     end
 end
 
+"""
+
+    new_obj, new_state = modify_stateful(f, (obj,state), optic)
+
+Here `f` has signature `f(::Value, ::State) -> Tuple{NewValue, NewState}`.
+"""
+function modify_stateful end
+
+@inline function modify_stateful(f, (obj, state), optic::Properties)
+    let f=f, obj=obj, state=state
+        modify_stateful_context((obj, state), optic) do _, fn, pr, st
+            f(getfield(pr, known(fn)), st)
+        end
+    end
+end
+
+@generated function modify_stateful_context(f, (obj, state1)::T, optic::Properties) where T
+    _modify_stateful_inner(T)
+end
+
+# Separated for testing object/state combinations without restarts
+function _modify_stateful_inner(::Type{<:Tuple{O,S}}) where {O,S}
+    modifications = []
+    vals = Expr(:tuple)
+    fns = fieldnames(O)
+    local st1 = :state0
+    local st2 = :state1
+    for (i, fn) in enumerate(fns)
+        v = Symbol("val$i")
+        st1 = Symbol("state$i")
+        st2 = Symbol("state$(i+1)")
+        ms = if O <: Tuple 
+            :(($v, $st2) = f(obj, StaticInt{$(QuoteNode(fn))}(), props, $st1))
+        else
+            :(($v, $st2) = f(obj, StaticSymbol{$(QuoteNode(fn))}(), props, $st1))
+        end
+        push!(modifications, ms)
+        push!(vals.args, v)
+    end
+    patch = O <: Tuple ? vals : :(NamedTuple{$fns}($vals))
+    Expr(:block,
+        :(props = getproperties(obj)),
+        modifications...,
+        :(patch = $patch),
+        :(new_obj = maybesetproperties($st2, obj, patch)),
+        :(new_state = maybesetstate($st2, obj, patch)),
+        :(return (setproperties(obj, patch), $st2)),
+    )
+end
+
+maybesetproperties(state, obj, patch) = setproperties(obj, patch)
+maybesetstate(state, obj, patch) = state
+
 abstract type AbstractQuery end
 
 """
@@ -395,44 +426,101 @@ Query(; select=Any, descend=x -> true, optic=Properties()) = Query(select, desce
 
 OpticStyle(::Type{<:AbstractQuery}) = SetBased()
 
-@inline function (q::AbstractQuery)(obj)
-    let obj=obj, q=q
-        mapobject(obj, _inner(q.optic), Splat()) do o
-            if q.select_condition(o)
-                (_getouter(o, q.optic),)
-            elseif q.descent_condition(o)
-                q(o) # also a tuple
-            else
-                ()
-            end
-        end
+struct Context{Select,Descend,Optic<:Union{ComposedOptic,Properties}} <: AbstractQuery
+    select_condition::Select
+    descent_condition::Descend
+    optic::Optic
+end
+
+
+struct ContextState{V}
+    vals::V
+end
+struct GetAllState{V}
+    vals::V
+end
+struct SetAllState{C,V,I}
+    change::C
+    vals::V
+    itr::I
+end
+
+pop(x) = first(x), Base.tail(x)
+push(x, val) = (x..., val)
+push(x::GetAllState, val) = GetAllState(push(x.vals, val))
+
+(q::Query)(obj) = getall(obj, q)
+
+function getall(obj, q)
+    initial_state = GetAllState(())
+    _, final_state = modify_stateful((obj, initial_state), q) do o, s
+        new_state = push(s, outer(q.optic, o, s))
+        o, new_state
+    end
+    return final_state.vals
+end
+
+function setall(obj, q, vals)
+    initial_state = SetAllState(Unchanged(), vals, 1)
+    final_obj, _ = modify_stateful((obj, initial_state), q) do o, s
+        new_output = outer(q.optic, o, s)
+        new_state = SetAllState(Changed(), s.vals, s.itr + 1)
+        new_output, new_state
+    end
+    return final_obj
+end
+
+function context(f, obj, q)
+    initial_state = GetAllState(())
+    _, final_state = modify_stateful_context((obj, initial_state), Properties()) do o, fn, pr, s
+        new_state = push(s, f(o, known(fn)))
+        o, new_state
     end
+    return final_state.vals
 end
 
-set(obj, q::AbstractQuery, vals) = _set(obj, q, (vals, 1))[1][1]
+modify(f, obj, q::Query) = setall(obj, q, map(f, getall(obj, q)))
 
-@inline function _set(obj, q::AbstractQuery, (vals, itr))
-    let obj=obj, q=q, vals=vals, itr=itr
-        mapobject(obj, _inner(q.optic), MaybeConstruct(), itr) do o, itr::Int
-            if q.select_condition(o)
-                _setouter(o, q.optic, vals[itr]) => Changed(), itr + 1
-            elseif q.descent_condition(o)
-                _set(o, q, (vals, itr)) # Will be marked as Changed()/Unchanged()
-            else
-                o => Unchanged(), itr 
-            end
+@inline function modify_stateful(f::F, (obj, state), q::Query) where F
+    modify_stateful((obj, state), inner(q.optic)) do o, s
+        if q.select_condition(o)
+            f(o, s)
+        elseif q.descent_condition(o)
+            ds = descent_state(s)
+            o, s = modify_stateful(f::F, (o, ds), q)
+            o, merge_state(s, ds)
+        else
+            o, s
         end
     end
 end
 
-modify(f, obj, q::Query) = set(obj, q, map(f, q(obj)))
+maybesetproperties(state::GetAllState, obj, patch) = obj
+maybesetproperties(state::SetAllState, obj, patch) =
+    maybesetproperties(state.change, state, obj, patch)
+maybesetproperties(::Changed, state::SetAllState, obj, patch) = setproperties(obj, patch)
+maybesetproperties(::Unchanged, state::SetAllState, obj, patch) = obj
+
+descent_state(state::SetAllState) = SetAllState(Unchanged(), state.vals, state.itr)
+descent_state(state) = state
+
+merge_state(s1::SetAllState, s2) = SetAllState(anychanged(s1, s2), s2.vals, s2.itr)
+merge_state(s1, s2) = s2
+
+anychanged(s1, s2) = anychanged(s1.change, s2.change)
+anychanged(::Unchanged, ::Unchanged) = Unchanged()
+anychanged(::Unchanged, ::Changed) = Changed()
+anychanged(::Changed, ::Unchanged) = Changed()
+anychanged(::Changed, ::Changed) = Changed()
+
+inner(optic) = optic
+inner(optic::ComposedOptic) = optic.inner
+
+outer(optic, o, state::GetAllState) = o
+outer(optic::ComposedOptic, o, state::GetAllState) = optic.outer(o)
+outer(optic::ComposedOptic, o, state::SetAllState) = set(o, optic.outer, state.vals[state.itr])
+outer(optic, o, state::SetAllState) = state.vals[state.itr]
 
-@inline _inner(optic::ComposedOptic) = optic.inner
-@inline _inner(optic) = optic
-@inline _getouter(o, optic::ComposedOptic) = optic.outer(o)
-@inline _getouter(o, optic) = o
-@inline _setouter(o, optic::ComposedOptic, v) = set(o, optic.outer, v)
-@inline _setouter(o, optic, v) = v
 
 ################################################################################
 ##### Lenses
diff --git a/src/setindex.jl b/src/setindex.jl
index 919c38e3..7c40308d 100644
--- a/src/setindex.jl
+++ b/src/setindex.jl
@@ -2,6 +2,10 @@ Base.@propagate_inbounds function setindex(args...)
     Base.setindex(args...)
 end
 
+Base.@propagate_inbounds function setindex(xs::NamedTuple{K}, v, i::Int) where K
+    Base.setindex(xs, v, K[i])
+end
+
 @inline setindex(::Base.RefValue, val) = Ref(val)
 
 Base.@propagate_inbounds function setindex(xs::AbstractArray, v, I...)
diff --git a/src/sugar.jl b/src/sugar.jl
index c7aefd87..055a9173 100644
--- a/src/sugar.jl
+++ b/src/sugar.jl
@@ -132,7 +132,7 @@ end
 _select(select, val) = :($(esc(val)) -> $(esc(select)))
 function _optics(ex)
     obj, optic = parse_obj_optic(ex)
-    :($optic ∘ Fields())
+    :($optic ∘ Properties())
 end
 
 
@@ -150,10 +150,10 @@ function setallmacro(ex)
     if @capture(ex, ((lens_ for var_ in obj_ if select_) = vals_))
         select = _select(select, var)
         optic =_optics(lens)
-        :(set($(esc(obj)), Query(; select=$select, optic=$optic), $(esc(vals))))
+        :(setall($(esc(obj)), Query(; select=$select, optic=$optic), $(esc(vals))))
     elseif @capture(ex, ((lens_ for var_ in obj_) = vals_))
         optic = _optics(lens)
-        :(set($(esc(obj)), Query(; optic=$optic), $(esc(vals))))
+        :(setall($(esc(obj)), Query(; optic=$optic), $(esc(vals))))
     else 
         error("@getall must be passed a generator")
     end
diff --git a/test/test_queries.jl b/test/test_queries.jl
index 59ac4a99..5a502722 100644
--- a/test/test_queries.jl
+++ b/test/test_queries.jl
@@ -1,104 +1,63 @@
 using Accessors, Test, BenchmarkTools, Static
+using Accessors: setall, getall, context
 
 obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=6.0,), [1,]))
 vals = (1.0, 2.0, 3.0, 4.0)
 
-
 # Fields is the default
 q = Query(; 
-    select=x -> x isa NamedTuple, 
-    descend=x -> x isa Tuple, 
-    optic = (Accessors.@optic _.a) ∘ Accessors.Fields()
-    # optic = Accessors.Fields()
-)
-slowq = Query(; 
     select=x -> x isa NamedTuple, 
     descend=x -> x isa Tuple, 
     optic = (Accessors.@optic _.a) ∘ Accessors.Properties()
+    # optic = Accessors.Properties()
 )
 
-q(obj)
-@code_native q(obj)
-@code_native slowq(obj)
-
-@code_warntype q(obj)
-@code_warntype slowq(obj)
+println("getall")
+getall(obj, q)
+@code_native getall(obj, q)
+@code_warntype getall(obj, q)
 
-
-println("get")
-@benchmark $q($obj)
-@benchmark $slowlens($obj)
-@test q(obj) == slowq(obj) == (17.0, 6.0)
+@benchmark getall($obj, $q)
+@test getall(obj, q) == (17.0, 6.0)
 
 missings_obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
-@test Query(ismissing)(missings_obj) === (missing, missing, missing)
-@benchmark Query(ismissing)($missings_obj)
+@test getall(missings_obj, Query(ismissing)) === (missing, missing, missing)
+@benchmark getall($missings_obj, Query(ismissing))
 
-println("set")
+println("setall")
 # Need a wrapper so we don't have to pass in the starting iterator
-set(obj, q, vals) 
-@benchmark set($obj, $q, $vals)
-
-# Package deinition
-# set(obj, q::Query, vals) = _set(obj, q, (vals, 1))[1][1]
-# REPL definition
-f(obj, q::Query, vals) = Accessors._set(obj, q, (vals, 1))[1][1]
-
-julia> @btime f(obj, q, vals)
-  19.302 ns (1 allocation: 80 bytes)
-(7, (a = 1.0, b = 2.0f0), ("3", 4, 5.0), ((x = 19, a = 2.0), [1]))
-
-julia> @btime set(obj, q, vals)
-  89.260 ns (6 allocations: 464 bytes)
-(7, (a = 1.0, b = 2.0f0), ("3", 4, 5.0), ((x = 19, a = 2.0), [1]))
-
-@eval Accessors begin
-    set(obj, q::Query, vals) = _set(obj, q, (vals, 1))[1][1]
-end
-
-@btime f(obj, q, vals)
-@btime set(obj, q, vals) 
+setall(obj, q, vals) 
+@benchmark setall($obj, $q, $vals)
+@code_native setall(obj, q, vals)
+@code_warntype setall(obj, q, vals)
 
 # @btime Accessors.set($obj, $slowlens, $vals)
-@test Accessors.set(obj, lens, vals) == 
+@test setall(obj, q, vals) == 
     (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=2.0,), [1]))
 
-@code_warntype set(obj, lens, vals) 
-@code_native set(obj, lens, vals) 
-@code_native Accessors._set(obj, lens, (vals, 1))[1]
-
-# using Cthulhu
+using Cthulhu
+@descend getall(obj, q)
 # using ProfileView
 # @profview  for i in 1:1000000 Accessors.set(obj, lens, vals) end
-# @descend Accessors.set(obj, lens, vals) 
 
 println("unstable set")
-unstable_lens = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x -> x isa NamedTuple)
-@btime set($obj, $unstable_lens, $vals)
+unstable_q = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x -> x isa NamedTuple)
+@btime setall($obj, $unstable_q, $vals)
 # slow_unstable_lens = Accessors.Query(; select=x -> x isa Number && x > 4, optic=Properties())
 # @btime Accessors.set($obj, $slow_unstable_lens, $vals))
 
 # Somehow modify compiles away almost completely
-@btime modify(x -> 10x, $obj, $lens)
+@btime modify(x -> 10x, $obj, $q)
+
+# Context
+obj = (b=2, c=2)
+@test context((o, fn) -> fn, obj, q) == (:b, :c)
+@test context((o, fn) -> typeof(o), obj, q) == (typeof(obj), typeof(obj))
+@btime context((o, fn) -> fn, $obj, $q)
 
 # Macros
-@test (@getall missings_obj isa Number) == (1, 2)
+@test (@getall (x for x in missings_obj if x isa Number)) == (1, 2)
 expected = (a=missing, b=5, c=(d=missing, e=(f=missing, g=6)))
-@test (@setall missings_obj isa Number = (5, 6)) === expected
-@getall missings_obj isa Number
-@setall missings_obj isa Number = (5, 6)
-
-using Accessors
-
-obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
-
-q = Query(ismissing);
-
-obj2 = set(obj, q, ["first", "wins", "here"])
-
-set(obj2, Query(x -> x isa String), ["second", "should", "win"])
-
-@getall missings_obj isa Number
-missings_obj = (a=missing, b=(1, (; a=4)), c=(d=missing, e=(f=missing, g=2)))
-@setall (x for x in missings_obj if x isa Missing) = (100.0, 200.0, 300.0)
-@getall (x[1] for x in missings_obj if x isa NamedTuple) !(descend isa Dict)
+@test (@setall (x for x in missings_obj if x isa Number) = (5, 6)) === expected
+@getall (x[2].g for x in missings_obj if x isa NamedTuple)
+@setall (x[2].g for x in missings_obj if x isa NamedTuple) = (5, 6)

From 9ad188640f04a332515ecd2ba380ca2cb3d383e4 Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Sun, 20 Jun 2021 00:34:52 +1000
Subject: [PATCH 03/10] working but slow

---
 src/optics.jl        | 130 +++++++++++++++++++++----------------------
 test/test_queries.jl |  36 ++++++------
 2 files changed, 83 insertions(+), 83 deletions(-)

diff --git a/src/optics.jl b/src/optics.jl
index b2bb340a..3140ae9d 100644
--- a/src/optics.jl
+++ b/src/optics.jl
@@ -42,8 +42,7 @@ julia> obj = (a=1, b=2); lens=@optic _.a; val = 100;
 
 julia> set(obj, lens, val)
 (a = 100, b = 2)
-```
-See also [`modify`](@ref).
+``` See also [`modify`](@ref).
 """
 function set end
 
@@ -346,15 +345,7 @@ Here `f` has signature `f(::Value, ::State) -> Tuple{NewValue, NewState}`.
 """
 function modify_stateful end
 
-@inline function modify_stateful(f, (obj, state), optic::Properties)
-    let f=f, obj=obj, state=state
-        modify_stateful_context((obj, state), optic) do _, fn, pr, st
-            f(getfield(pr, known(fn)), st)
-        end
-    end
-end
-
-@generated function modify_stateful_context(f, (obj, state1)::T, optic::Properties) where T
+@generated function modify_stateful(f::F, (obj, state)::T, optic::Properties) where {T,F}
     _modify_stateful_inner(T)
 end
 
@@ -363,29 +354,29 @@ function _modify_stateful_inner(::Type{<:Tuple{O,S}}) where {O,S}
     modifications = []
     vals = Expr(:tuple)
     fns = fieldnames(O)
-    local st1 = :state0
-    local st2 = :state1
     for (i, fn) in enumerate(fns)
         v = Symbol("val$i")
-        st1 = Symbol("state$i")
-        st2 = Symbol("state$(i+1)")
-        ms = if O <: Tuple 
-            :(($v, $st2) = f(obj, StaticInt{$(QuoteNode(fn))}(), props, $st1))
+        st = if S <: ContextState 
+            if O <: Tuple 
+                :(ContextState(state.vals, obj, StaticInt{$(QuoteNode(fn))}()))
+            else
+                :(ContextState(state.vals, obj, StaticSymbol{$(QuoteNode(fn))}()))
+            end
         else
-            :(($v, $st2) = f(obj, StaticSymbol{$(QuoteNode(fn))}(), props, $st1))
+            :state
         end
+        ms = :(($v, state) = f(getfield(props, $(QuoteNode(fn))), $st))
         push!(modifications, ms)
         push!(vals.args, v)
     end
     patch = O <: Tuple ? vals : :(NamedTuple{$fns}($vals))
-    Expr(:block,
-        :(props = getproperties(obj)),
-        modifications...,
-        :(patch = $patch),
-        :(new_obj = maybesetproperties($st2, obj, patch)),
-        :(new_state = maybesetstate($st2, obj, patch)),
-        :(return (setproperties(obj, patch), $st2)),
-    )
+    start = :(props = getproperties(obj))
+    rest = MacroTools.@q begin
+        patch = $patch
+        new_obj = maybesetproperties(state, obj, patch)
+        return (new_obj, state)
+    end
+    Expr(:block, start, modifications..., rest) 
 end
 
 maybesetproperties(state, obj, patch) = setproperties(obj, patch)
@@ -426,15 +417,10 @@ Query(; select=Any, descend=x -> true, optic=Properties()) = Query(select, desce
 
 OpticStyle(::Type{<:AbstractQuery}) = SetBased()
 
-struct Context{Select,Descend,Optic<:Union{ComposedOptic,Properties}} <: AbstractQuery
-    select_condition::Select
-    descent_condition::Descend
-    optic::Optic
-end
-
-
-struct ContextState{V}
+struct ContextState{V,O,FN}
     vals::V
+    obj::O
+    fn::FN
 end
 struct GetAllState{V}
     vals::V
@@ -445,57 +431,69 @@ struct SetAllState{C,V,I}
     itr::I
 end
 
-pop(x) = first(x), Base.tail(x)
-push(x, val) = (x..., val)
-push(x::GetAllState, val) = GetAllState(push(x.vals, val))
+const GetStates = Union{GetAllState,ContextState}
+
+@inline pop(x) = first(x), Base.tail(x)
+@inline push(x, val) = (x..., val)
+@inline push(x::GetAllState, val) = GetAllState(push(x.vals, val))
+@inline push(x::ContextState, val) = ContextState(push(x.vals, val), nothing, nothing)
 
 (q::Query)(obj) = getall(obj, q)
 
-function getall(obj, q)
+getall(obj, q) = _getall(obj, q).vals
+function _getall(obj, q::Q) where Q<:Query
     initial_state = GetAllState(())
-    _, final_state = modify_stateful((obj, initial_state), q) do o, s
-        new_state = push(s, outer(q.optic, o, s))
-        o, new_state
+    _, final_state = let q=q
+        modify_stateful((obj, initial_state), q) do o, s
+            new_state = push(s, outer(q.optic, o, s))
+            o, new_state
+        end
     end
-    return final_state.vals
+    final_state
 end
 
-function setall(obj, q, vals)
+function setall(obj, q::Q, vals) where Q<:Query
     initial_state = SetAllState(Unchanged(), vals, 1)
-    final_obj, _ = modify_stateful((obj, initial_state), q) do o, s
-        new_output = outer(q.optic, o, s)
-        new_state = SetAllState(Changed(), s.vals, s.itr + 1)
-        new_output, new_state
+    final_obj, _ = let obj=obj, q=q, initial_state=initial_state
+        modify_stateful((obj, initial_state), q) do o, s
+            new_output = outer(q.optic, o, s)
+            new_state = SetAllState(Changed(), s.vals, s.itr + 1)
+            new_output, new_state
+        end
     end
     return final_obj
 end
 
-function context(f, obj, q)
-    initial_state = GetAllState(())
-    _, final_state = modify_stateful_context((obj, initial_state), Properties()) do o, fn, pr, s
-        new_state = push(s, f(o, known(fn)))
-        o, new_state
+function context(f::F, obj, q::Q) where {F,Q<:Query}
+    initial_state = ContextState((), nothing, nothing)
+    _, final_state = let f=f
+        modify_stateful((obj, initial_state), q) do o, s
+            new_state = push(s, f(s.obj, known(s.fn)))
+            o, new_state
+        end
     end
     return final_state.vals
 end
 
 modify(f, obj, q::Query) = setall(obj, q, map(f, getall(obj, q)))
 
-@inline function modify_stateful(f::F, (obj, state), q::Query) where F
-    modify_stateful((obj, state), inner(q.optic)) do o, s
-        if q.select_condition(o)
-            f(o, s)
-        elseif q.descent_condition(o)
-            ds = descent_state(s)
-            o, s = modify_stateful(f::F, (o, ds), q)
-            o, merge_state(s, ds)
-        else
-            o, s
+@inline function modify_stateful(f::F, (obj, state), q::Q) where {F,Q<:Query}
+    let f=f, q=q
+        modify_stateful((obj, state), inner(q.optic)) do o, s
+            if (q::Q).select_condition(o)
+                (f::F)(o, s)
+            elseif (q::Q).descent_condition(o)
+                ds = descent_state(s)
+                o, ns = modify_stateful(f::F, (o, ds), q::Q)
+                o, merge_state(ds, ns)
+            else
+                o, s
+            end
         end
     end
 end
 
-maybesetproperties(state::GetAllState, obj, patch) = obj
+maybesetproperties(state::GetStates, obj, patch) = obj
 maybesetproperties(state::SetAllState, obj, patch) =
     maybesetproperties(state.change, state, obj, patch)
 maybesetproperties(::Changed, state::SetAllState, obj, patch) = setproperties(obj, patch)
@@ -516,8 +514,8 @@ anychanged(::Changed, ::Changed) = Changed()
 inner(optic) = optic
 inner(optic::ComposedOptic) = optic.inner
 
-outer(optic, o, state::GetAllState) = o
-outer(optic::ComposedOptic, o, state::GetAllState) = optic.outer(o)
+outer(optic, o, state::GetStates) = o
+outer(optic::ComposedOptic, o, state::GetStates) = optic.outer(o)
 outer(optic::ComposedOptic, o, state::SetAllState) = set(o, optic.outer, state.vals[state.itr])
 outer(optic, o, state::SetAllState) = state.vals[state.itr]
 
@@ -532,7 +530,7 @@ function (l::PropertyLens{field})(obj) where {field}
 end
 
 @inline function set(obj, l::PropertyLens{field}, val) where {field}
-    patch = (;field => val)
+    patch = (; field => val)
     setproperties(obj, patch)
 end
 
diff --git a/test/test_queries.jl b/test/test_queries.jl
index 5a502722..99722716 100644
--- a/test/test_queries.jl
+++ b/test/test_queries.jl
@@ -1,9 +1,7 @@
 using Accessors, Test, BenchmarkTools, Static
 using Accessors: setall, getall, context
-
-obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=6.0,), [1,]))
+obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=6.0,)), [1])
 vals = (1.0, 2.0, 3.0, 4.0)
-
 # Fields is the default
 q = Query(; 
     select=x -> x isa NamedTuple, 
@@ -11,36 +9,35 @@ q = Query(;
     optic = (Accessors.@optic _.a) ∘ Accessors.Properties()
     # optic = Accessors.Properties()
 )
-
-println("getall")
 getall(obj, q)
+
 @code_native getall(obj, q)
 @code_warntype getall(obj, q)
 
 @benchmark getall($obj, $q)
 @test getall(obj, q) == (17.0, 6.0)
 
+# using ProfileView, Cthulhu
+# @descend getall(obj, q)
+# f(obj, q) = for i in 1:10000000 getall(obj, q) end
+# @profview f(obj, q)
+
 missings_obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
 @test getall(missings_obj, Query(ismissing)) === (missing, missing, missing)
 @benchmark getall($missings_obj, Query(ismissing))
 
-println("setall")
 # Need a wrapper so we don't have to pass in the starting iterator
 setall(obj, q, vals) 
 @benchmark setall($obj, $q, $vals)
+# using ProfileView
+# @profview for i in 1:1000000 setall(obj, q, vals) end
 @code_native setall(obj, q, vals)
 @code_warntype setall(obj, q, vals)
 
 # @btime Accessors.set($obj, $slowlens, $vals)
 @test setall(obj, q, vals) == 
-    (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=2.0,), [1]))
-
-using Cthulhu
-@descend getall(obj, q)
-# using ProfileView
-# @profview  for i in 1:1000000 Accessors.set(obj, lens, vals) end
+    (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=2.0,)), [1])
 
-println("unstable set")
 unstable_q = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x -> x isa NamedTuple)
 @btime setall($obj, $unstable_q, $vals)
 # slow_unstable_lens = Accessors.Query(; select=x -> x isa Number && x > 4, optic=Properties())
@@ -50,10 +47,15 @@ unstable_q = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x -> x
 @btime modify(x -> 10x, $obj, $q)
 
 # Context
-obj = (b=2, c=2)
-@test context((o, fn) -> fn, obj, q) == (:b, :c)
-@test context((o, fn) -> typeof(o), obj, q) == (typeof(obj), typeof(obj))
-@btime context((o, fn) -> fn, $obj, $q)
+q = Query(; 
+    select=x -> x isa Int, 
+    descend=x -> x isa NamedTuple, 
+    optic = Accessors.Properties()
+)
+obj2 = (1.0, :a, (b=2, c=2))
+@test context((o, fn) -> fn, obj2, q) == (:b, :c)
+@test context((o, fn) -> typeof(o), obj2, q) == (typeof(obj2[3]), typeof(obj2[3]))
+@btime context((o, fn) -> fn, $obj2, $q)
 
 # Macros
 @test (@getall (x for x in missings_obj if x isa Number)) == (1, 2)

From 4aaacf5f8f9f5a5978ede3b17a233173d29501b2 Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Mon, 26 Jul 2021 15:36:25 +1000
Subject: [PATCH 04/10] use modify_stateful

---
 src/optics.jl | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/optics.jl b/src/optics.jl
index 3140ae9d..25d7553d 100644
--- a/src/optics.jl
+++ b/src/optics.jl
@@ -250,7 +250,10 @@ end
 abstract type ObjectMap end
 
 OpticStyle(::Type{<:ObjectMap}) = ModifyBased()
-modify(f, o, optic::ObjectMap) = mapobject(f, o, optic, Construct)
+function modify(f, o, optic::ObjectMap) 
+    obj, state = modify_stateful(f, (o, nothing), optic)
+    return obj
+end
 
 """
     Properties()
@@ -269,7 +272,7 @@ julia> set(obj, Properties(), "hi")
 julia> modify(x -> 2x, obj, Properties())
 (a = 2, b = 4, c = 6)
 ```
-Based on [`mapobject`](@ref).
+Based on [`modify_stateful`](@ref).
 
 $EXPERIMENTAL
 """

From 0fd6a953b4c2bfc01926d989a2ec921f6f43d592 Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Mon, 26 Jul 2021 15:36:56 +1000
Subject: [PATCH 05/10] add Static to deps

---
 Project.toml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Project.toml b/Project.toml
index 3e844484..34a1ef3f 100644
--- a/Project.toml
+++ b/Project.toml
@@ -11,6 +11,7 @@ Future = "9fa8497b-333b-5362-9e8d-4d0656e87820"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 MacroTools = "1914dd2f-81c6-5fcd-8719-6d5c9610ff09"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
+Static = "aedffcd0-7271-4cad-89d0-dc628f76c6d3"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [compat]
@@ -19,6 +20,7 @@ CompositionsBase = "0.1"
 ConstructionBase = "1.2"
 MacroTools = "0.4.4, 0.5"
 Requires = "0.5, 1.0"
+Static = "0.3"
 StaticNumbers = "0.3"
 julia = "1.3"
 

From 225d2bad73044d63f9a49bdb617051ec1b7de172 Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Sun, 1 Aug 2021 23:14:14 +1000
Subject: [PATCH 06/10] test macros

---
 test/test_queries.jl | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/test/test_queries.jl b/test/test_queries.jl
index 99722716..2160cc8a 100644
--- a/test/test_queries.jl
+++ b/test/test_queries.jl
@@ -61,5 +61,6 @@ obj2 = (1.0, :a, (b=2, c=2))
 @test (@getall (x for x in missings_obj if x isa Number)) == (1, 2)
 expected = (a=missing, b=5, c=(d=missing, e=(f=missing, g=6)))
 @test (@setall (x for x in missings_obj if x isa Number) = (5, 6)) === expected
-@getall (x[2].g for x in missings_obj if x isa NamedTuple)
-@setall (x[2].g for x in missings_obj if x isa NamedTuple) = (5, 6)
+@test (@getall (x[2].g for x in missings_obj if x isa NamedTuple)) == (2,)
+@test (@setall (x[2].g for x in missings_obj if x isa NamedTuple) = 5) ==
+    (a=missing, b=1, c=(d=missing, e=(f=missing, g=5)))

From e331a11b46101443fb3a94bce3eec7c0c36dd46d Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Mon, 2 Aug 2021 01:18:43 +1000
Subject: [PATCH 07/10] cleanup

---
 src/optics.jl        | 111 ++++++++++++++++++-------------------------
 src/sugar.jl         |  45 ++++++++++++++----
 test/test_optics.jl  |   2 -
 test/test_queries.jl |  34 ++++++-------
 4 files changed, 95 insertions(+), 97 deletions(-)

diff --git a/src/optics.jl b/src/optics.jl
index 25d7553d..1514c2d2 100644
--- a/src/optics.jl
+++ b/src/optics.jl
@@ -42,7 +42,8 @@ julia> obj = (a=1, b=2); lens=@optic _.a; val = 100;
 
 julia> set(obj, lens, val)
 (a = 100, b = 2)
-``` See also [`modify`](@ref).
+```
+See also [`modify`](@ref).
 """
 function set end
 
@@ -134,32 +135,9 @@ else
     using Base: Returns
 end
 
-
 struct Changed end
 struct Unchanged end
 
-struct MaybeConstruct end
-_constructor(::MaybeConstruct, ::Type{T}) where T = constructorof(T)
-
-struct List end
-_constructor(::List, ::Type) = tuple
-
-struct Splat end
-_constructor(::Splat, ::Type) = _splat_all
-
-_splat_all(args...) = _splat_all(args)  
-@generated function _splat_all(args::A) where A<:Tuple  
-    exp = Expr(:tuple)
-    for i in fieldnames(A)
-        push!(exp.args, Expr(:..., :(args[$i])))
-    end
-    exp
-end
-
-
-struct Constant{V}
-    value::V
-end
 
 @inline function _set(obj, optic, val, ::ModifyBased)
     modify(Returns(val), obj, optic)
@@ -216,7 +194,9 @@ $EXPERIMENTAL
 struct Elements end
 OpticStyle(::Type{<:Elements}) = ModifyBased()
 
-modify(f, obj, ::Elements) = map(f, obj)
+function modify(f, obj, ::Elements)
+    map(f, obj)
+end
 
 """
     If(modify_condition)
@@ -247,39 +227,20 @@ function modify(f, obj, w::If)
     end
 end
 
-abstract type ObjectMap end
-
-OpticStyle(::Type{<:ObjectMap}) = ModifyBased()
-function modify(f, o, optic::ObjectMap) 
-    obj, state = modify_stateful(f, (o, nothing), optic)
-    return obj
-end
-
 """
-    Properties()
+    mapproperties(f, obj)
 
-Access all properties of an objects.
+Construct a copy of `obj`, with each property replaced by
+the result of applying `f` to it.
 
 ```jldoctest
 julia> using Accessors
 
-julia> obj = (a=1, b=2, c=3)
-(a = 1, b = 2, c = 3)
-
-julia> set(obj, Properties(), "hi")
-(a = "hi", b = "hi", c = "hi")
+julia> obj = (a=1, b=2);
 
-julia> modify(x -> 2x, obj, Properties())
-(a = 2, b = 4, c = 6)
+julia> Accessors.mapproperties(x -> x+1, obj)
+(a = 2, b = 3)
 ```
-Based on [`modify_stateful`](@ref).
-
-$EXPERIMENTAL
-"""
-struct Properties <: ObjectMap end
-
-"""
-    maproperties()
 
 # Implementation
 
@@ -291,8 +252,8 @@ $EXPERIMENTAL
 """
 function mapproperties end
 
-function mapproperties(f, nt::Union{Tuple,NamedTuple})
-    map(f, nt)
+function mapproperties(f, nt::NamedTuple)
+    map(f,nt)
 end
 
 function mapproperties(f, obj)
@@ -301,8 +262,30 @@ function mapproperties(f, obj)
     return setproperties(obj, patch)
 end
 
-skip(::Splat) = true
-skip(x) = false
+"""
+    Properties()
+
+Access all properties of an objects.
+
+```jldoctest
+julia> using Accessors
+
+julia> obj = (a=1, b=2, c=3)
+(a = 1, b = 2, c = 3)
+
+julia> set(obj, Properties(), "hi")
+(a = "hi", b = "hi", c = "hi")
+
+julia> modify(x -> 2x, obj, Properties())
+(a = 2, b = 4, c = 6)
+```
+Based on [`mapproperties`](@ref).
+
+$EXPERIMENTAL
+"""
+struct Properties end
+OpticStyle(::Type{<:Properties}) = ModifyBased()
+modify(f, o, ::Properties) = mapproperties(f, o)
 
 """
     Recursive(descent_condition, optic)
@@ -341,10 +324,9 @@ function _modify(f, obj, r::Recursive, ::ModifyBased)
 end
 
 """
+    modify_stateful(f, (obj,state), optic) => Tuple{NewValue,NewState}
 
-    new_obj, new_state = modify_stateful(f, (obj,state), optic)
-
-Here `f` has signature `f(::Value, ::State) -> Tuple{NewValue, NewState}`.
+Here `f` has signature `f(::Value, ::State) => Tuple{NewValue,NewState}`.
 """
 function modify_stateful end
 
@@ -399,8 +381,8 @@ julia> using Accessors
 julia> obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
 (a = missing, b = 1, c = (d = missing, e = (f = missing, g = 2)))
 
-julia> set(obj, Query(ismissing), (1.0, 2.0, 3.0))
-(a = 1.0, b = 1, c = (d = 2.0, e = (f = 3.jjjjjjtk,rg, g = 2)))
+julia> 
+
 
 julia> obj = (1,2,(3,(4,5),6))
 (1, 2, (3, (4, 5), 6))
@@ -441,9 +423,8 @@ const GetStates = Union{GetAllState,ContextState}
 @inline push(x::GetAllState, val) = GetAllState(push(x.vals, val))
 @inline push(x::ContextState, val) = ContextState(push(x.vals, val), nothing, nothing)
 
-(q::Query)(obj) = getall(obj, q)
+(q::Query)(obj) = _getall(obj, q)
 
-getall(obj, q) = _getall(obj, q).vals
 function _getall(obj, q::Q) where Q<:Query
     initial_state = GetAllState(())
     _, final_state = let q=q
@@ -452,10 +433,10 @@ function _getall(obj, q::Q) where Q<:Query
             o, new_state
         end
     end
-    final_state
+    final_state.vals
 end
 
-function setall(obj, q::Q, vals) where Q<:Query
+function set(obj, q::Q, vals) where Q<:Query
     initial_state = SetAllState(Unchanged(), vals, 1)
     final_obj, _ = let obj=obj, q=q, initial_state=initial_state
         modify_stateful((obj, initial_state), q) do o, s
@@ -478,7 +459,7 @@ function context(f::F, obj, q::Q) where {F,Q<:Query}
     return final_state.vals
 end
 
-modify(f, obj, q::Query) = setall(obj, q, map(f, getall(obj, q)))
+modify(f, obj, q::Query) = set(obj, q, map(f, q(obj)))
 
 @inline function modify_stateful(f::F, (obj, state), q::Q) where {F,Q<:Query}
     let f=f, q=q
@@ -533,7 +514,7 @@ function (l::PropertyLens{field})(obj) where {field}
 end
 
 @inline function set(obj, l::PropertyLens{field}, val) where {field}
-    patch = (; field => val)
+    patch = (;field => val)
     setproperties(obj, patch)
 end
 
diff --git a/src/sugar.jl b/src/sugar.jl
index 055a9173..4b7fab96 100644
--- a/src/sugar.jl
+++ b/src/sugar.jl
@@ -91,10 +91,21 @@ function modifymacro(optictransform, f, obj_optic)
 end
 
 """
-    @getall f(obj, arg...)
-    @setall [x for x in obs if x isa Number] = values
+    @getall [x for x in obs if f(x)]
 
-@getall obj isa Number
+Get each `x` in `obj` that matches the condition `f`.
+
+This can be combined with other optics, e.g. 
+
+```julia
+julia> using Accessors
+
+julia> obj = ("1", 2, 3, (a=4, b="5"))
+("1", 2, 3, (a = 4, b = "5"))
+
+julia> @getall (x for x in obj if x isa Number && iseven(x))
+(2, 4)
+```
 """
 macro getall(ex)
     getallmacro(ex)
@@ -135,12 +146,26 @@ function _optics(ex)
     :($optic ∘ Properties())
 end
 
-
 """
-    @setall f(obj, arg...) = values
-    
-    @setall [x for x in obs if x isa Number] = values
+    @setall [x for x in obs if f(x)] = values
+
+Set each `x` in `obj` matching the condition `f` 
+to values from the `Tuple` or vector `values`.
 
+# Example
+
+Used combination with lenses to set the `b` field of the
+second item of all `Tuple`:
+
+```jldoctest
+julia> using Accessors
+
+julia> obj = ("x", (1, (a = missing, b = :y), (2, (a = missing, b = :b))))
+("x", (1, (a = missing, b = :y), (2, (a = missing, b = :b))))
+
+julia> @setall (x[2].b for x in obj if x isa Tuple) = (:x, :a)
+("x", (1, (a = missing, b = :x), (2, (a = missing, b = :b))))
+```
 """
 macro setall(ex)
     setallmacro(ex)
@@ -150,12 +175,12 @@ function setallmacro(ex)
     if @capture(ex, ((lens_ for var_ in obj_ if select_) = vals_))
         select = _select(select, var)
         optic =_optics(lens)
-        :(setall($(esc(obj)), Query(; select=$select, optic=$optic), $(esc(vals))))
+        :(set($(esc(obj)), Query(; select=$select, optic=$optic), $(esc(vals))))
     elseif @capture(ex, ((lens_ for var_ in obj_) = vals_))
         optic = _optics(lens)
-        :(setall($(esc(obj)), Query(; optic=$optic), $(esc(vals))))
+        :(set($(esc(obj)), Query(; optic=$optic), $(esc(vals))))
     else 
-        error("@getall must be passed a generator")
+        error("@setall must be passed a generator")
     end
 end
 
diff --git a/test/test_optics.jl b/test/test_optics.jl
index e0b2b1ae..9d90ddc4 100644
--- a/test/test_optics.jl
+++ b/test/test_optics.jl
@@ -43,8 +43,6 @@ end
     pt = Point(1f0, 2e0, 3)
     pt2 = @inferred modify(x->2x, pt, Properties())
     @test pt2 === Point(2f0, 4e0, 6)
-    @test (x=0, y=1, z=2) === 
-    @set pt |> Properties(pt) -= 1
 end
 
 @testset "Elements" begin
diff --git a/test/test_queries.jl b/test/test_queries.jl
index 2160cc8a..bde5ce33 100644
--- a/test/test_queries.jl
+++ b/test/test_queries.jl
@@ -9,13 +9,13 @@ q = Query(;
     optic = (Accessors.@optic _.a) ∘ Accessors.Properties()
     # optic = Accessors.Properties()
 )
-getall(obj, q)
+q(obj)
 
-@code_native getall(obj, q)
-@code_warntype getall(obj, q)
+@code_native q(obj)
+@code_warntype q(obj)
 
-@benchmark getall($obj, $q)
-@test getall(obj, q) == (17.0, 6.0)
+@benchmark $q($obj)
+@test q(obj) == (17.0, 6.0)
 
 # using ProfileView, Cthulhu
 # @descend getall(obj, q)
@@ -23,31 +23,25 @@ getall(obj, q)
 # @profview f(obj, q)
 
 missings_obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
-@test getall(missings_obj, Query(ismissing)) === (missing, missing, missing)
-@benchmark getall($missings_obj, Query(ismissing))
+@test Query(ismissing)(missings_obj) === (missing, missing, missing)
+@benchmark Query(ismissing)($missings_obj)
 
 # Need a wrapper so we don't have to pass in the starting iterator
-setall(obj, q, vals) 
-@benchmark setall($obj, $q, $vals)
+set(obj, q, vals) 
+@benchmark set($obj, $q, $vals)
 # using ProfileView
 # @profview for i in 1:1000000 setall(obj, q, vals) end
-@code_native setall(obj, q, vals)
-@code_warntype setall(obj, q, vals)
+@code_native set(obj, q, vals)
+@code_warntype set(obj, q, vals)
 
 # @btime Accessors.set($obj, $slowlens, $vals)
-@test setall(obj, q, vals) == 
+@test set(obj, q, vals) == 
     (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=2.0,)), [1])
 
-unstable_q = Accessors.Query(select=x -> x isa Float64 && x > 2, descend=x -> x isa NamedTuple)
-@btime setall($obj, $unstable_q, $vals)
-# slow_unstable_lens = Accessors.Query(; select=x -> x isa Number && x > 4, optic=Properties())
-# @btime Accessors.set($obj, $slow_unstable_lens, $vals))
-
-# Somehow modify compiles away almost completely
 @btime modify(x -> 10x, $obj, $q)
 
 # Context
-q = Query(; 
+q = Query(;
     select=x -> x isa Int, 
     descend=x -> x isa NamedTuple, 
     optic = Accessors.Properties()
@@ -62,5 +56,5 @@ obj2 = (1.0, :a, (b=2, c=2))
 expected = (a=missing, b=5, c=(d=missing, e=(f=missing, g=6)))
 @test (@setall (x for x in missings_obj if x isa Number) = (5, 6)) === expected
 @test (@getall (x[2].g for x in missings_obj if x isa NamedTuple)) == (2,)
-@test (@setall (x[2].g for x in missings_obj if x isa NamedTuple) = 5) ==
+@test (@setall (x[2].g for x in missings_obj if x isa NamedTuple) = 5) ===
     (a=missing, b=1, c=(d=missing, e=(f=missing, g=5)))

From 6e9efd6b7573944dfa6b404211c8b72c96de65e4 Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Mon, 2 Aug 2021 07:54:43 +0200
Subject: [PATCH 08/10] use old keyword syntax for 1.3

---
 src/sugar.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/sugar.jl b/src/sugar.jl
index 4b7fab96..8593e3c5 100644
--- a/src/sugar.jl
+++ b/src/sugar.jl
@@ -111,7 +111,7 @@ macro getall(ex)
     getallmacro(ex)
 end
 macro getall(ex, descend)
-    getallmacro(ex; descend)
+    getallmacro(ex; descend=descend)
 end
 
 function getallmacro(ex; descend=true)

From a55a7098cd68fa30d76df332bec13d0c8fe42cae Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Mon, 2 Aug 2021 15:06:58 +0200
Subject: [PATCH 09/10] document Query

---
 src/optics.jl | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/src/optics.jl b/src/optics.jl
index 1514c2d2..06b455dd 100644
--- a/src/optics.jl
+++ b/src/optics.jl
@@ -371,24 +371,22 @@ abstract type AbstractQuery end
 
 """
     Query(select, descend, optic)
+    Query(; select=Any, descend=x -> true, optic=Properties())
 
-Query an object recursively, choosing fields when `select` 
-returns `true`, and descending when `descend`.
+Query an object recursively, choosing fields where `select` 
+returns `true`, and descending when `descend` returns `true`.
 
 ```jldoctest
 julia> using Accessors
 
-julia> obj = (a=missing, b=1, c=(d=missing, e=(f=missing, g=2)))
-(a = missing, b = 1, c = (d = missing, e = (f = missing, g = 2)))
-
-julia> 
-
+julia> q = Query(; select=x -> x isa Int, descend=x -> x isa Tuple)
+Query{var"#5#7", var"#6#8", Properties}(var"#5#7"(), var"#6#8"(), Properties())
 
-julia> obj = (1,2,(3,(4,5),6))
-(1, 2, (3, (4, 5), 6))
+julia> obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), ((x=19, a=6.0,)), [1])
+(7, (a = 17.0, b = 2.0f0), ("3", 4, 5.0), (x = 19, a = 6.0), [1])
 
-julia> modify(x -> 100x, obj, Recursive(x -> (x isa Tuple), Elements()))
-(100, 200, (300, (400, 500), 600))
+julia> q(obj)
+(7, 4)
 ```
 $EXPERIMENTAL
 """
@@ -397,7 +395,7 @@ struct Query{Select,Descend,Optic<:Union{ComposedOptic,Properties}} <: AbstractQ
     descent_condition::Descend
     optic::Optic
 end
-Query(select, descend = x -> true) = Query(select, descend, Properties())
+Query(select, descend=x -> true) = Query(select, descend, Properties())
 Query(; select=Any, descend=x -> true, optic=Properties()) = Query(select, descend, optic)
 
 OpticStyle(::Type{<:AbstractQuery}) = SetBased()

From 36a7670d4a9994d7eeb9de017c52015e2f085d5c Mon Sep 17 00:00:00 2001
From: Rafael Schouten <rafaelschouten@gmail.com>
Date: Tue, 3 Aug 2021 13:32:52 +0200
Subject: [PATCH 10/10] Update src/sugar.jl

Co-authored-by: Jan Weidner <jw3126@gmail.com>
---
 src/sugar.jl | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/sugar.jl b/src/sugar.jl
index 8593e3c5..2edee6a5 100644
--- a/src/sugar.jl
+++ b/src/sugar.jl
@@ -134,7 +134,7 @@ function getallmacro(ex; descend=true)
         optic = _optics(lens)
         :([Query($select, $descend, $optic)($(esc(obj)))...])
     else 
-        error("@getall must be passed a generator")
+        error("@getall must be passed a generator or array comprehension")
     end
 end
 
@@ -403,4 +403,3 @@ function show_composition_order(io::IO, optic::ComposedOptic)
     show_composition_order(io, optic.inner)
     print(io, ")")
 end
-