Switch maps (and consequently most of the code) to using instances

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

Isomorphism.agda

@@ -63,27 +63,29 @@ module TransportFiniteHeight
         portChain₂ (done₂ a₂≈a₁) = done₁ (g-preserves-≈₂ a₂≈a₁)
         portChain₂ (step₂ {b₁} {b₂} (b₁≼b₂ , b₁̷≈b₂) b₂≈b₂' c) = step₁ (≈₁-trans (≈₁-sym (g-⊔-distr b₁ b₂)) (g-preserves-≈₂ b₁≼b₂) , g-preserves-̷≈ b₁̷≈b₂) (g-preserves-≈₂ b₂≈b₂') (portChain₂ c)
 
-    isFiniteHeightLattice : IsFiniteHeightLattice B height _≈₂_ _⊔₂_ _⊓₂_
-    isFiniteHeightLattice =
-        let
-            open Chain.Height (IsFiniteHeightLattice.fixedHeight fhlA)
-                using ()
-                renaming (⊥ to ⊥₁; ⊤ to ⊤₁; bounded to bounded₁; longestChain to c)
-        in record
-            { isLattice = lB
-            ; fixedHeight = record
-                { ⊥ = f ⊥₁
-                ; ⊤ = f ⊤₁
-                ; longestChain = portChain₁ c
-                ; bounded = λ c' → bounded₁ (portChain₂ c')
-                }
+    open Chain.Height (IsFiniteHeightLattice.fixedHeight fhlA)
+        using ()
+        renaming (⊥ to ⊥₁; ⊤ to ⊤₁; bounded to bounded₁; longestChain to c)
+
+    instance
+        fixedHeight = record
+            { ⊥ = f ⊥₁
+            ; ⊤ = f ⊤₁
+            ; longestChain = portChain₁ c
+            ; bounded = λ c' → bounded₁ (portChain₂ c')
             }
 
-    finiteHeightLattice : FiniteHeightLattice B
-    finiteHeightLattice = record
-        { height = height
-        ; _≈_ = _≈₂_
-        ; _⊔_ = _⊔₂_
-        ; _⊓_ = _⊓₂_
-        ; isFiniteHeightLattice = isFiniteHeightLattice
-        }
+        isFiniteHeightLattice : IsFiniteHeightLattice B height _≈₂_ _⊔₂_ _⊓₂_
+        isFiniteHeightLattice = record
+            { isLattice = lB
+            ; fixedHeight = fixedHeight
+            }
+
+        finiteHeightLattice : FiniteHeightLattice B
+        finiteHeightLattice = record
+            { height = height
+            ; _≈_ = _≈₂_
+            ; _⊔_ = _⊔₂_
+            ; _⊓_ = _⊓₂_
+            ; isFiniteHeightLattice = isFiniteHeightLattice
+            }