feat(client): changed the tiny existing render code to use the update…

…d core

packages/client/spago.dhall

@@ -16,6 +16,9 @@
   , "effect"
   , "console"
   , "canvas"
+  , "run"
+  , "fixed-points"
+  , "matryoshka"
   , "lunarflow-utils"
   , "lunarflow-core"
   , "lunarflow-geometry"

packages/client/src/Render.purs

@@ -0,0 +1,43 @@
+module Lunarbox.Render where
+
+import Prelude
+import Data.List as List
+import Lunarflow.Ast (AstF(..))
+import Lunarflow.Geometry.Foreign (fitIntoBounds)
+import Lunarflow.Geometry.Types as Shape
+import Lunarflow.Layout (Layout, LayoutF)
+import Matryoshka (Algebra, cata)
+import Run (Run)
+import Run.Reader (READER, local)
+
+type RenderContext
+  = { doNotRender :: List.List Int
+    }
+
+type RenderM r
+  = Run ( reader :: READER RenderContext | r )
+
+-- | Prepare stuff for rendering inside a lambda.
+shiftContext :: Int -> RenderContext -> RenderContext
+shiftContext by ctx = ctx { doNotRender = ((+) by) <$> ctx.doNotRender }
+
+{-- 
+So:
+- When we encounter a lambda, we draw the body and then the box around it
+- When we encouner a var, we check where it is in scope and draw until here
+--}
+render :: forall r. Layout -> RenderM r Shape.Shape
+render = cata algebra
+  where
+  algebra :: Algebra LayoutF (RenderM r Shape.Shape)
+  algebra (Lambda { args } body) = do
+    bodyShape <- local (shiftContext $ List.length args) body
+    let
+      bounds = fitIntoBounds bodyShape
+    pure
+      $ Shape.group {}
+          [ Shape.fromBounds { fill: "transparent", stroke: "red" } bounds
+          , bodyShape
+          ]
+
+  algebra _ = pure mempty