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diff --git a/src/Inky/Data/Row.idr b/src/Inky/Data/Row.idr
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+module Inky.Data.Row
+
+import public Data.So
+import public Inky.Data.Context
+import public Inky.Data.SnocList.Quantifiers
+
+import Inky.Data.SnocList.Elem
+import Inky.Data.Irrelevant
+import Inky.Decidable
+
+public export
+FreshIn : String -> SnocList String -> Type
+FreshIn n = All (\x => So (x /= n))
+
+public export
+AllFresh : SnocList String -> Type
+AllFresh = Pairwise (So .: (/=))
+
+public export
+record Row (a : Type) where
+  constructor MkRow
+  context : Context a
+  0 fresh : AllFresh context.names
+
+%name Row row
+
+public export
+(.names) : Row a -> SnocList String
+row.names = row.context.names
+
+-- Interfaces ------------------------------------------------------------------
+
+public export
+Functor Row where
+  map f row = MkRow (map (map f) row.context) (rewrite mapNames f row.context in row.fresh)
+
+public export
+Foldable Row where
+  foldr f x row = foldr (\x, y => f x.value y) x row.context
+  foldl f x row = foldl (\x, y => f x y.value) x row.context
+  null row = null row.context
+  foldlM f x row = foldlM (\x, y => f x y.value) x row.context
+  foldMap f row = foldMap (f . value) row.context
+
+-- Equality --------------------------------------------------------------------
+
+export
+soUnique : (prf1, prf2 : So b) -> prf1 = prf2
+soUnique Oh Oh = Refl
+
+export
+freshInUnique : (freshIn1, freshIn2 : x `FreshIn` sx) -> freshIn1 = freshIn2
+freshInUnique [<] [<] = Refl
+freshInUnique (freshIn1 :< prf1) (freshIn2 :< prf2) =
+  cong2 (:<) (freshInUnique freshIn1 freshIn2) (soUnique prf1 prf2)
+
+export
+freshUnique : (fresh1, fresh2 : AllFresh sx) -> fresh1 = fresh2
+freshUnique [<] [<] = Refl
+freshUnique (fresh1 :< freshIn1) (fresh2 :< freshIn2) =
+  cong2 (:<) (freshUnique fresh1 fresh2) (freshInUnique freshIn1 freshIn2)
+
+export
+rowCong :
+  {0 ctx1, ctx2 : Context a} ->
+  {0 fresh1 : AllFresh ctx1.names} ->
+  {0 fresh2 : AllFresh ctx2.names} ->
+  ctx1 = ctx2 -> MkRow ctx1 fresh1 = MkRow ctx2 fresh2
+rowCong Refl = rewrite freshUnique fresh1 fresh2 in Refl
+
+-- Smart Constructors ----------------------------------------------------------
+
+public export
+Lin : Row a
+Lin = MkRow [<] [<]
+
+public export
+(:<) :
+  (row : Row a) -> (x : Assoc a) ->
+  (0 fresh : x.name `FreshIn` row.names) =>
+  Row a
+row :< x = MkRow (row.context :< x) (row.fresh :< fresh)
+
+public export
+fromAll : (row : Row a) -> All (const b) row.names -> Row b
+fromAll row sx = MkRow (fromAll row.context sx) (rewrite fromAllNames row.context sx in row.fresh)
+
+-- Operations ------------------------------------------------------------------
+
+export
+isFresh :
+  (names : SnocList String) ->
+  (name : String) ->
+  Dec' (Irrelevant $ name `FreshIn` names)
+isFresh names name =
+  map irrelevant (\contra, prfs => anyNegAll contra $ relevant names prfs.value) $
+  all (\x => (decSo $ x /= name).forget) names
+
+export
+extend : Row a -> Assoc a -> Maybe (Row a)
+extend row x with (isFresh row.names x.name)
+  _ | True `Because` Forget prf = Just (row :< x)
+  _ | False `Because` _ = Nothing
+
+-- Search ----------------------------------------------------------------------
+
+noLookupFresh :
+  (ctx : Context a) ->
+  (0 freshIn : n `FreshIn` ctx.names) ->
+  Not (Elem (n :- x) ctx)
+noLookupFresh (sx :< (n :- x)) (freshIn :< prf) Here with ((decEq n n).reason) | ((decEq n n).does)
+  _ | _ | True = void $ absurd prf
+  _ | contra | False = void $ contra Refl
+noLookupFresh (sx :< (k :- _)) (freshIn :< prf) (There i) = noLookupFresh sx freshIn i
+
+doLookupUnique :
+  (ctx : Context a) ->
+  (0 fresh : AllFresh ctx.names) ->
+  (i : Elem (n :- x) ctx) ->
+  (j : Elem (n :- y) ctx) ->
+  the (x ** Elem (n :- x) ctx) (x ** i) = (y ** j)
+doLookupUnique (ctx :< (n :- x)) (fresh :< freshIn) Here Here = Refl
+doLookupUnique (ctx :< (n :- x)) (fresh :< freshIn) Here (There j) = void $ noLookupFresh ctx freshIn j
+doLookupUnique (ctx :< (n :- z)) (fresh :< freshIn) (There i) Here = void $ noLookupFresh ctx freshIn i
+doLookupUnique (ctx :< (k :- z)) (fresh :< freshIn) (There i) (There j) =
+  cong (\(x ** i) => (x ** There i)) $
+  doLookupUnique ctx fresh i j
+
+export
+lookupUnique :
+  (row : Row a) ->
+  (i : Elem (n :- x) row.context) ->
+  (j : Elem (n :- y) row.context) ->
+  the (x ** Elem (n :- x) row.context) (x ** i) = (y ** j)
+lookupUnique row i j = doLookupUnique row.context row.fresh i j
+
+-- Removal ---------------------------------------------------------------------
+
+dropElemFreshIn :
+  (ctx : Context a) -> n `FreshIn` ctx.names -> (i : Elem nx ctx) ->
+  n `FreshIn` (dropElem ctx i).names
+dropElemFreshIn (ctx :< (n :- x)) (freshIn :< prf) Here = freshIn
+dropElemFreshIn (ctx :< (n :- x)) (freshIn :< prf) (There i) = dropElemFreshIn ctx freshIn i :< prf
+
+export
+dropElemFresh :
+  (ctx : Context a) -> AllFresh ctx.names -> (i : Elem nx ctx) ->
+  AllFresh (dropElem ctx i).names
+dropElemFresh (ctx :< (n :- x)) (fresh :< freshIn) Here = fresh
+dropElemFresh (ctx :< (n :- x)) (fresh :< freshIn) (There i) =
+  dropElemFresh ctx fresh i :< dropElemFreshIn ctx freshIn i