From 11ebab929e78cd9e4282c4c6fc6bffb177c2d816 Mon Sep 17 00:00:00 2001
From: Penelope Yong <penelopeysm@gmail.com>
Date: Thu, 20 Aug 2026 01:22:50 +0100
Subject: [PATCH 1/4] Add `Draw` struct

---
 HISTORY.md      | 11 +++++++++++
 Project.toml    |  2 +-
 src/VarNames.jl |  5 +++++
 src/draw.jl     | 32 ++++++++++++++++++++++++++++++++
 test/draw.jl    | 16 ++++++++++++++++
 5 files changed, 65 insertions(+), 1 deletion(-)
 create mode 100644 HISTORY.md
 create mode 100644 src/draw.jl
 create mode 100644 test/draw.jl

diff --git a/HISTORY.md b/HISTORY.md
new file mode 100644
index 0000000..6d1b32a
--- /dev/null
+++ b/HISTORY.md
@@ -0,0 +1,11 @@
+# 0.1.1
+
+Added the `Draw` struct, which bundles a `VarNamedTuple` of parameter values with a `NamedTuple` of extra information, as well as the accessor functions `parameters` and `extras`.
+This is intended to represent a single MCMC sample.
+
+`Draw` is structurally the same as what used to be called `ParamsWithStats` in DynamicPPL.
+
+# 0.1.0
+
+Initial release.
+This is a direct port of code from AbstractPPL and DynamicPPL, with one major change: `@vn` is now an alias for `@varname`, which is hopefully helpful since it gets used quite a lot.
diff --git a/Project.toml b/Project.toml
index 3a706a8..4072f2e 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "VarNames"
 uuid = "09a315b2-63fc-4165-8d7f-d59368e770cc"
-version = "0.1.0"
+version = "0.1.1"
 authors = ["Penelope Yong <penelopeysm@gmail.com>", "Markus Hauru <markus@mhauru.org>"]
 
 [deps]
diff --git a/src/VarNames.jl b/src/VarNames.jl
index 7c5ab57..0d1cfe2 100644
--- a/src/VarNames.jl
+++ b/src/VarNames.jl
@@ -70,6 +70,11 @@ export VarNamedTuple,
     SkipTemplate,
     @vnt
 
+include("draw.jl")
+export Draw
+export parameters
+export extras
+
 using BangBang: push!!, empty!!, setindex!!
 export push!!, empty!!, setindex!!
 
diff --git a/src/draw.jl b/src/draw.jl
new file mode 100644
index 0000000..55f95e2
--- /dev/null
+++ b/src/draw.jl
@@ -0,0 +1,32 @@
+"""
+    Draw{P<:VarNamedTuple,S<:NamedTuple}
+
+A struct that bundles a set of parameter values stored as a `VarNamedTuple`, along with a
+`NamedTuple` of extra information associated with this set of values (for example, this can
+be used to store log-probability values, etc.).
+
+In VarNames.jl, this struct is not used at all; however, it is defined here so that other
+packages can dispatch on it easily.
+"""
+struct Draw{P<:VarNamedTuple,S<:NamedTuple}
+    parameters::P
+    extras::S
+end
+
+"""
+    VarNames.parameters(draw::Draw)::VarNamedTuple
+
+Returns the parameters of the draw as a `VarNamedTuple`.
+"""
+function parameters(draw::Draw)
+    return draw.parameters
+end
+
+"""
+    VarNames.extras(draw::Draw)::NamedTuple
+
+Returns the extra information of the draw as a `NamedTuple`.
+"""
+function extras(draw::Draw)
+    return draw.extras
+end
diff --git a/test/draw.jl b/test/draw.jl
new file mode 100644
index 0000000..5f3f257
--- /dev/null
+++ b/test/draw.jl
@@ -0,0 +1,16 @@
+module DrawTests
+
+using VarNames
+using Test
+
+@testset "draw" begin
+    # Since it's just a bare struct, just test its API.
+    vnt = VarNamedTuple(x = 0.5, y = randn(3))
+    nt = (a = :hello, logjoint = randn())
+    d = Draw(vnt, nt)
+
+    @test parameters(d) == vnt
+    @test extras(d) == nt
+end
+
+end # module DrawTests

From 8e6939b3ffd15685ff4373df4626a518042c98a2 Mon Sep 17 00:00:00 2001
From: Penelope Yong <penelopeysm@gmail.com>
Date: Thu, 20 Aug 2026 01:28:49 +0100
Subject: [PATCH 2/4] Actually run the tests

---
 test/runtests.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/runtests.jl b/test/runtests.jl
index 05fbd3e..da996e2 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -9,4 +9,5 @@ using Test
     include("varname/leaves.jl")
     include("varname/serialize.jl")
     include("varnamedtuple.jl")
+    include("draw.jl")
 end

From ed70a434f1afc0fa0ae78128cba74b0bccc05fcf Mon Sep 17 00:00:00 2001
From: Penelope Yong <penelopeysm@gmail.com>
Date: Thu, 20 Aug 2026 01:29:43 +0100
Subject: [PATCH 3/4] Document

---
 docs/src/vnt/api.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/docs/src/vnt/api.md b/docs/src/vnt/api.md
index a9b477d..73470f3 100644
--- a/docs/src/vnt/api.md
+++ b/docs/src/vnt/api.md
@@ -16,3 +16,9 @@ templated_setindex!!
 densify!!
 skeleton
 ```
+
+```@docs
+Draw
+parameters
+extras
+```

From 57d1425214d7b83afa50653f709f5f720831c927 Mon Sep 17 00:00:00 2001
From: Penelope Yong <penelopeysm@gmail.com>
Date: Thu, 20 Aug 2026 01:30:05 +0100
Subject: [PATCH 4/4] Format

---
 test/draw.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/draw.jl b/test/draw.jl
index 5f3f257..4f9da41 100644
--- a/test/draw.jl
+++ b/test/draw.jl
@@ -5,8 +5,8 @@ using Test
 
 @testset "draw" begin
     # Since it's just a bare struct, just test its API.
-    vnt = VarNamedTuple(x = 0.5, y = randn(3))
-    nt = (a = :hello, logjoint = randn())
+    vnt = VarNamedTuple(x=0.5, y=randn(3))
+    nt = (a=:hello, logjoint=randn())
     d = Draw(vnt, nt)
 
     @test parameters(d) == vnt