simplify some things

src/LetInBlock.tsx

@@ -1,4 +1,4 @@
-import type { EditorState } from "./Editor";
+import { Editor, type EditorState } from "./Editor";
 import type { Dynamic, State2Props } from "./util/extra";
 
 
@@ -16,6 +16,36 @@ interface LetInBlockProps extends State2Props<LetInBlockState> {
 }
 
 
-export function LetInBlock({env, name, value, inner, resolved, onResolve}) {
-  
-}
+export function LetInBlock({state, setState, onResolve}: LetInBlockProps) {
+  const {env, name, value, inner, resolved} = state;
+  const onChangeName = (e: React.ChangeEvent<HTMLInputElement>) => {
+    setState({...state, name: e.target.value});
+  }
+  return <span className="letIn">
+    <div className="decl">
+      let <input
+        className='editable'
+        value={name}
+        placeholder="<variable name>"
+        onChange={onChangeName}
+        /> =
+      <Editor
+        state={value}
+        filter={() => true}
+        onResolve={(state: EditorState) => {} }
+        onCancel={() => {} }
+        setState={(state: EditorState) => {} }
+        />
+      in
+    </div>
+    <div className="inner">
+      <Editor
+        state={inner}
+        filter={() => true}
+        onResolve={(state: EditorState) => {} }
+        onCancel={() => {} }
+        setState={(state: EditorState) => {} }
+        />
+    </div>
+  </span>
+}