can disable syntactic sugar also for let...in... blocks + nicer looking fn input parameters

src/LetInBlock.tsx

@@ -3,12 +3,13 @@ import { useContext, useEffect, useRef } from "react";
 
 import { Editor, type EditorState } from "./Editor";
 import { EnvContext } from "./EnvContext";
-import { evalEditorBlock, evalLetInBlock, makeInnerEnv, scoreResolved } from "./eval";
+import { evalEditorBlock, makeInnerEnv, scoreResolved } from "./eval";
 import { type State2Props } from "./Editor";
 import { autoInputWidth } from "./util/dom_trickery";
 
 import "./LetInBlock.css";
 import type { SuggestionType } from "./InputBlock";
+import { CommandContext } from "./CommandContext";
 
 export interface LetInBlockState {
   kind: "let";
@@ -35,13 +36,14 @@ export function LetInBlock({state, setState, suggestionPriority}: LetInBlockProp
         state={state}
         setState={setState}
         suggestionPriority={suggestionPriority}
-        />    
+        />
     </div>
   </span>
 }
 
 function DeclColumns({state, setState, suggestionPriority}) {
   const env = useContext(EnvContext);
+  const globalContext = useContext(CommandContext);
   const {name, value, inner} = state;
 
   const setInner = callback => setState(state => ({...state, inner: callback(state.inner)}));
@@ -86,8 +88,8 @@ function DeclColumns({state, setState, suggestionPriority}) {
           onCancel={() => setState(state => state.inner)} // keep inner
           />
       </span>
-    {/* <span className="keyword column">in</span> */}
     {inner.kind === "let" &&
+     globalContext?.syntacticSugar &&
       <EnvContext value={innerEnv}>
         <DeclColumns
           state={inner}
@@ -101,11 +103,12 @@ function DeclColumns({state, setState, suggestionPriority}) {
 
 function InnerMost({state, setState, suggestionPriority}) {
   const env = useContext(EnvContext);
+  const globalContext = useContext(CommandContext);
   const setInner = callback => setState(state => ({...state, inner: callback(state.inner)}));
   const valueResolved = evalEditorBlock(state.value, env);
   const innerEnv = makeInnerEnv(env, state.name, valueResolved);
   const onCancel = () => setState(state => state.value);
-  if (state.inner.kind === "let") {
+  if (state.inner.kind === "let" && globalContext?.syntacticSugar) {
     return <EnvContext value={innerEnv}>
         <InnerMost
           state={state.inner}