diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index ebe24a2..ab03867 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -10,7 +10,7 @@ importers:
     dependencies:
       dope2:
         specifier: git+https://deemz.org/git/joeri/dope2.git
-        version: git+https://deemz.org/git/joeri/dope2.git#3b8548e9af5528069f07ec62519e263511ecc34b
+        version: git+https://deemz.org/git/joeri/dope2.git#d531c48a9298f318d089b900009f32cb9f04a53a
       react:
         specifier: ^19.1.0
         version: 19.1.0
@@ -633,8 +633,8 @@ packages:
     resolution: {integrity: sha512-g7nH6P6dyDioJogAAGprGpCtVImJhpPk/roCzdb3fIh61/s/nPsfR6onyMwkCAR/OlC3yBC0lESvUoQEAssIrw==}
     engines: {node: '>= 0.8'}
 
-  dope2@git+https://deemz.org/git/joeri/dope2.git#3b8548e9af5528069f07ec62519e263511ecc34b:
-    resolution: {commit: 3b8548e9af5528069f07ec62519e263511ecc34b, repo: https://deemz.org/git/joeri/dope2.git, type: git}
+  dope2@git+https://deemz.org/git/joeri/dope2.git#d531c48a9298f318d089b900009f32cb9f04a53a:
+    resolution: {commit: d531c48a9298f318d089b900009f32cb9f04a53a, repo: https://deemz.org/git/joeri/dope2.git, type: git}
     version: 0.0.1
 
   dunder-proto@1.0.1:
@@ -1758,7 +1758,7 @@ snapshots:
 
   depd@2.0.0: {}
 
-  dope2@git+https://deemz.org/git/joeri/dope2.git#3b8548e9af5528069f07ec62519e263511ecc34b:
+  dope2@git+https://deemz.org/git/joeri/dope2.git#d531c48a9298f318d089b900009f32cb9f04a53a:
     dependencies:
       functional-red-black-tree: 1.0.1
 
diff --git a/src/App.tsx b/src/App.tsx
index 01a7d28..1c8859e 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,11 +1,15 @@
 // import { useState } from 'react'
+import { useEffect, useState } from 'react';
 import './App.css'
-import { Editor } from './Editor'
+import { Editor, initialEditorState, type EditorState } from './Editor'
 
-import {module2Env, ModuleStd} from "dope2";
 
-function App() {
-  const env = module2Env(ModuleStd);
+export function App() {
+  const [state, setState] = useState<EditorState>(initialEditorState);
+
+  useEffect(() => {
+    // console.log("EDITOR STATE:", state);
+  }, [state]);
 
   return (
     <>
@@ -14,7 +18,7 @@ function App() {
       </header>
 
       <main>
-        <Editor env={env}></Editor>
+        <Editor state={state} setState={setState}></Editor>
       </main>
 
       <footer>
@@ -23,5 +27,3 @@ function App() {
     </>
   )
 }
-
-export default App
diff --git a/src/CallBlock.css b/src/CallBlock.css
new file mode 100644
index 0000000..961beb2
--- /dev/null
+++ b/src/CallBlock.css
@@ -0,0 +1,65 @@
+.functionBlock {
+  border: solid 1px darkgray;
+  display: inline-block;
+  margin: 1px;
+}
+
+.functionName {
+  text-align: center;
+
+}
+
+
+.inputParam:after {
+  content: "";
+  position: absolute;
+  border: solid 10px transparent;
+  border-left-color: rgba(242, 253, 146);
+  margin-left: 0px;
+}
+
+.inputParam {
+  height: 20px;
+  margin-right: 20px;
+  /* vertical-align: ; */
+  /* margin-left: 0; */
+  display: inline-block;
+  /* border: solid 1px black; */
+  background-color: rgba(242, 253, 146);
+  /* border-radius: 10px; */
+}
+
+
+
+.typeAnnot {
+  display: inline-block;
+  vertical-align: top;
+}
+
+
+
+
+/* .outputParam:before {
+  content: "";
+  position: absolute;
+  width: 0px;
+  height: 0px;
+  margin-left: -28px;
+  margin-top: 0px;
+  border-style: solid;
+  border-color: orange;
+  border-width: 14px;
+  border-left-color: transparent;
+} */
+
+.outputParam {
+  vertical-align: top;
+  /* margin-left: 28px; */
+  padding: 0px;
+  /* padding-left: 14px; */
+  display: inline-block;
+  /* border: solid 2px orange; */
+  background-color: rgb(233, 224, 205);
+  /* border-radius: 10px; */
+  width: 100%;
+}
diff --git a/src/CallBlock.tsx b/src/CallBlock.tsx
new file mode 100644
index 0000000..f0b955e
--- /dev/null
+++ b/src/CallBlock.tsx
@@ -0,0 +1,75 @@
+import type { Dynamic, State2Props } from "./util/extra";
+import { Editor, type EditorState } from "./Editor";
+
+import "./CallBlock.css";
+
+export interface CallBlockState {
+  kind: "call";
+  env: any;
+  fn: EditorState;
+  input: EditorState;
+}
+
+interface CallBlockProps extends State2Props<CallBlockState> {
+  onResolve: (d: Dynamic) => void;
+}
+
+export function CallBlock({ state: {kind, env, fn, input}, setState, onResolve }: CallBlockProps) {
+  const setFn = (fn: EditorState) => {
+    setState({kind, env, fn, input});
+  }
+  const setInput = (input: EditorState) => {
+    setState({kind, env, fn, input});
+  }
+  return <span className="functionBlock">
+    <div className="functionName">
+    &#119891;&#119899;&nbsp;
+      <Editor state={fn} setState={setFn}/>
+    </div>
+    <div className="functionParams">
+      <div className="outputParam">
+      <div className="inputParam">
+        <Editor state={input} setState={setInput} />
+      </div>
+      result
+      </div>
+    </div>
+  </span>;
+}
+
+// function FunctionBlock({env, done, name, funDynamic}) {
+//   const functionType = getType(funDynamic);
+//   const inType = functionType.params[0](functionType);
+//   const [outDynamic, setOutDynamic] = useState<any>(null);
+//   const [input, setInput] = useState<any>(null);
+//   const gotInput = (name, inDynamic) => {
+//     setInput([name, inDynamic]);
+//     const outDynamic = apply(inDynamic)(funDynamic);
+//     setOutDynamic(outDynamic);
+//     // propagate result up
+//     done(outDynamic);
+//   };
+//   return <span className="functionBlock">
+//     <div className="functionName">
+//     &#119891;&#119899;&nbsp;
+//       {name}
+//       {/* <Type type={functionType}/> */}
+//     </div>
+//     <div className="functionParams">
+//       <div className="outputParam">
+//       <div className="inputParam">
+//         {
+//           (input === null)
+//             ? <InputBlock env={env} done={gotInput} type={inType} />
+//             : <DynamicBlock env={env} name={input[0]} dynamic={input[1]}/>
+//         }
+//       </div>
+//       {
+//           (input === null)
+//             ? <>&nbsp;</>
+//             : <DynamicBlock env={env} name="" dynamic={outDynamic} />
+//         }
+//       </div>
+//     </div>
+//   </span>;
+// }
\ No newline at end of file
diff --git a/src/Editor.tsx b/src/Editor.tsx
index caeb66c..8a2f873 100644
--- a/src/Editor.tsx
+++ b/src/Editor.tsx
@@ -1,138 +1,100 @@
-import { useEffect, useRef, useState } from "react";
-import {growPrefix, suggest, getType, symbolFunction, symbolProduct, symbolSum, symbolDict, symbolSet, symbolList, symbolSetIterator, symbolDictIterator, getSymbol, getHumanReadableName} from "dope2";
+import { getSymbol, getType, module2Env, ModuleStd, symbolFunction } from "dope2";
 
-import "./Editor.css";
+import { InputBlock, type InputBlockState } from "./InputBlock";
+import { type Dynamic, type State2Props } from "./util/extra";
+import { CallBlock, type CallBlockState } from "./CallBlock";
 
-export function Editor({env}) {
-  return <Block env={env} />;
+interface LetInBlockState {
+  kind: "let";
+  env: any;
+  name: string;
+  value: EditorState;
+  inner: EditorState;
 }
 
-function getCursorPosition() {
-  const selection = window.getSelection();
-  if (selection) {
-    const range = selection.getRangeAt(0);
-    const clonedRange = range.cloneRange();
-    return clonedRange.startOffset;
+interface LambdaBlockState {
+  kind: "lambda";
+  paramName: string;
+  expr: EditorState;
+}
+
+export type EditorState =
+    InputBlockState
+  | CallBlockState
+  | LetInBlockState
+  | LambdaBlockState;
+
+export const initialEditorState: EditorState = {
+  kind: "input",
+  env: module2Env(ModuleStd),
+  text: "",
+  resolved: undefined,
+};
+
+type EditorProps = State2Props<EditorState>;
+
+const dontFilter = () => true;
+
+export function Editor({state, setState}: EditorProps) {
+  let onResolve;
+  switch (state.kind) {
+    case "input":
+      onResolve = (resolved: InputBlockState) => {
+        console.log('resolved!', state, resolved);
+        if (resolved) {
+          const type = getType(resolved.resolved);
+          if (getSymbol(type) === symbolFunction) {
+            console.log('function!');
+            // we were InputBlock
+            // now we become FunctionBlock
+            setState({
+              kind: "call",
+              env: state.env,
+              fn: resolved,
+              input: initialEditorState,
+            })
+          }
+        }
+        // const type = getType(state.resolved);
+        // if (getSymbol(type) === symbolFunction) {
+        //   console.log('function!');
+        //   console.log('editor state:', state);
+        // }
+      }
+      return <InputBlock state={state} setState={setState} filter={dontFilter} onResolve={onResolve} />;
+    case "call":
+      onResolve = (d: Dynamic) => {}
+      return <CallBlock state={state} setState={setState} onResolve={onResolve} />;
+    case "let":
+      return <></>;
+    case "lambda":
+      return <></>;
   }
 }
 
-function setCursorPosition(elem, pos) {
-  const range = document.createRange();
-  range.selectNode(elem);
-  range.setStart(elem, pos);
-  range.setEnd(elem, pos);
-  const selection = window.getSelection();
-  if (!selection) {
-    console.log('no selection!')
-  }
-  selection?.removeAllRanges();
-  selection?.addRange(range);
-}
+// function DynamicBlock({env, name, dynamic}) {
+//   const type = getType(dynamic);
+//   if (getSymbol(type) === symbolFunction) {
+//     return <FunctionBlock env={env} name={name} funDynamic={dynamic} />;
+//   }
+//   else return <>{getInst(dynamic).toString()} :: <Type type={type}/></>;
+// }
 
-function Block({env}) {
-  const [text, setText] = useState("edit me!");
-  const ref = useRef<any>(null);
-  const singleSuggestion = growPrefix(env.name2dyn)(text);
-  const suggestions = suggest(env.name2dyn)(text)(16);
-  const [i, setI] = useState(0);
-  const resetFocus = () => {
-    ref.current?.focus();
-  };
-  useEffect(resetFocus, [ref.current])
-  const onSelect = ([name]) => {
-    setText(name);
-    ref.current.innerText = name;
-    setCursorPosition(ref.current.lastChild, name.length);
-    setI(0);
-  }
-  const onInput = e => {
-    const pos = getCursorPosition();
-    setText(e.target.innerText);
-    setCursorPosition(e.target.lastChild, pos);
-  };
-  const onKeyDown = e => {
-    if (e.key === "Tab") {
-      const newText = text + singleSuggestion;
-      setText(newText);
-      ref.current.innerText = newText;
-      setCursorPosition(ref.current.lastChild, newText.length);
-      e.preventDefault();
-      return;
-    }
-    if (e.key === "ArrowDown") {
-      setI((i + 1) % suggestions.length);
-      e.preventDefault();
-      return;
-    }
-    if (e.key === "ArrowUp") {
-      setI((i - 1) % suggestions.length);
-      e.preventDefault();
-      return;
-    }
-    if (e.key === "Enter") {
-      onSelect(suggestions[i]);
-      e.preventDefault();
-      return;
-    }
-  };
-  return <span>
-    <span ref={ref} contentEditable="plaintext-only" onInput={onInput} tabIndex={0} onKeyDown={onKeyDown} onBlur={() =>{
-      // hacky, but couldn't find another way:
-      setTimeout(resetFocus, 0);
-    }}></span>
-    <Suggestions suggestions={suggestions} onSelect={onSelect} i={i} setI={setI}/>
-    <span className="text-block suggest">{singleSuggestion}</span>
-  </span>;
-}
+// function InputBlock({env, done, type}) {
+//   const filterInputType = ([_, dynamic]) => {
+//     try {
+//       unify(type, getType(dynamic));
+//       return true;
+//     } catch (e) {
+//       if (!(e instanceof UnifyError)) {
+//         console.error(e);
+//       }
+//       return false;
+//     }
+//   }
+//   return <>
+//     <span className="typeAnnot"><InputBlock env={env} done={done} filter={filterInputType} /></span>
+//     <span className="typeAnnot">:: <Type type={type}/></span>
+//   </>;
+// }
 
-function Suggestions({suggestions, onSelect, i, setI}) {
-  return (suggestions.length > 0) ?
-    <div className="suggestions">
-      {suggestions.map(([name, dynamic], j) => <div key={`${i}_${name}`} className={i===j?"selected":""} onClick={() => setI(j)} onDoubleClick={() => onSelect(suggestions[i])}>{name} :: <Type type={getType(dynamic)}/></div>)}
-    </div>
-    : <></>;
-}
-
-
-function Type({type}) {
-  const symbol = getSymbol(type);
-  switch (symbol) {
-    case symbolFunction:
-      return <BinaryType type={type} cssClass="functionType" infix="&rarr;" prefix="" suffix=""/>;
-    case symbolProduct:
-      return <BinaryType type={type} cssClass="productType" infix="&#10799;" prefix="" suffix=""/>;
-    case symbolSum:
-      return <BinaryType type={type} cssClass="sumType" infix="+" prefix="" suffix=""/>;
-    case symbolDict:
-      return <BinaryType type={type} cssClass="dictType" infix="&rArr;" prefix="{" suffix="}"/>;
-    case symbolSet:
-      return <UnaryType type={type} cssClass="setType" prefix="{" suffix="}" />;
-    case symbolList:
-      return <UnaryType type={type} cssClass="listType" prefix="[" suffix="]" />;
-    case symbolSetIterator:
-      return <UnaryType type={type} cssClass="setType iteratorType" prefix="{*" suffix="}" />;
-    case symbolDictIterator:
-      return <BinaryType type={type} cssClass="dictType iteratorType" infix="*&rArr;" prefix="{" suffix="}"/>;
-  
-      default:
-      return <div className="type">{getHumanReadableName(symbol)}</div>
-  }
-}
-
-function BinaryType({type, cssClass, infix, prefix, suffix}) {
-  return <div className={`type ${cssClass}`}>
-    {prefix}
-    <Type type={type.params[0](type)}/>
-    <span className="infix">{infix}</span>
-    <Type type={type.params[1](type)}/>
-    {suffix}
-  </div>
-}
-
-function UnaryType({type, cssClass, prefix, suffix}) {
-  return <div className={`type ${cssClass}`}>
-    {prefix}
-    <Type type={type.params[0](type)}/>
-    {suffix}
-  </div>
-}
\ No newline at end of file
diff --git a/src/InputBlock.css b/src/InputBlock.css
new file mode 100644
index 0000000..db54782
--- /dev/null
+++ b/src/InputBlock.css
@@ -0,0 +1,25 @@
+.suggest {
+  color: #aaa;
+}
+.suggestions { 
+  position: absolute;
+  /* display: inline-block; */
+  /* top: 20px; */
+  border: solid 1px lightgrey;
+  cursor: pointer;
+  max-height: calc(100vh - 44px);
+  overflow: scroll;
+}
+.selected {
+  background-color: dodgerblue;
+  color: white;
+}
+.editable {
+  outline: 0px solid transparent;
+  display: inline-block;
+}
+.border-around-input {
+  border: 1px solid black;
+  padding: 1px;
+  margin: 1px;
+}
\ No newline at end of file
diff --git a/src/InputBlock.tsx b/src/InputBlock.tsx
new file mode 100644
index 0000000..87b0940
--- /dev/null
+++ b/src/InputBlock.tsx
@@ -0,0 +1,149 @@
+import { Double, getType, Int, newDynamic, trie } from "dope2";
+import { focusNextElement, focusPrevElement, getCaretPosition, setRightMostCaretPosition } from "./util/dom_trickery";
+import { parseDouble, parseInt } from "./util/parse";
+
+import { useEffect, useRef, useState } from "react";
+import { Type } from "./Type";
+
+import "./InputBlock.css";
+import type { Dynamic, State2Props } from "./util/extra";
+
+export interface InputBlockState {
+  kind: "input";
+  env: any;
+  text: string;
+  resolved: undefined | Dynamic;
+}
+
+interface InputBlockProps extends State2Props<InputBlockState> {
+  filter: (ls: any[]) => boolean;
+  onResolve: (state: InputBlockState) => void;
+}
+
+export function InputBlock({ state: {kind, env, text, resolved}, setState, filter, onResolve }: InputBlockProps) {
+  const ref = useRef<any>(null);
+  useEffect(() => {
+    ref.current?.focus();
+    if (ref.current) {
+      ref.current.textContent = text;
+    }
+  }, []);
+
+  const [i, setI] = useState(0); // selected suggestion
+  const [haveFocus, setHaveFocus] = useState(false); // whether to render suggestions or not
+
+  const setText = (text: string) => {
+    setState({kind, env, text, resolved});
+  }
+  const setResolved = (resolved: Dynamic) => {
+    setState({kind, env, text, resolved});
+  }
+
+  const singleSuggestion = trie.growPrefix(env.name2dyn)(text);
+
+  const asDouble = parseDouble(text);
+  const asInt = parseInt(text);
+
+  const suggestions = [
+    ... (asDouble ? [[asDouble.toString(), newDynamic(asDouble)(Double)]] : []),
+    ... (asInt ? [[asInt.toString(), newDynamic(BigInt(asInt))(Int)]] : []),
+
+    ... (text !== '') ? trie.suggest(env.name2dyn)(text)(Infinity) : [],
+  ].filter(filter);
+
+  useEffect(() => {
+    setI(0); // reset
+    const found = trie.get(env.name2dyn)(text);
+    setResolved(found); // may be undefined
+  }, [text]);
+  
+
+  const onSelectSuggestion = ([name, _dynamic]) => {
+    // setText(name);
+    // ref.current.textContent = name;
+    // setRightMostCaretPosition(ref.current);
+    // setI(0);
+    onResolve({
+      env,
+      kind: "input",
+      resolved: _dynamic,
+      text: name,
+    });
+  };
+
+  const onInput = e => {
+    setText(e.target.textContent);
+  };
+
+  const onKeyDown = (e: React.KeyboardEvent) => {
+    const fns = {
+      Tab: () => {
+        if (e.shiftKey) {
+          focusPrevElement();
+          e.preventDefault();
+        }
+        else {
+          // not shift key
+          if (singleSuggestion.length > 0) {
+            const newText = text + singleSuggestion;
+            setText(newText);
+            ref.current.textContent = newText;
+            setRightMostCaretPosition(ref.current);
+            e.preventDefault();  
+          }
+        }
+      },
+      ArrowDown: () => {
+        setI((i + 1) % suggestions.length);
+        e.preventDefault();
+      },
+      ArrowUp: () => {
+        setI((i - 1) % suggestions.length);
+        e.preventDefault();  
+      },
+      ArrowLeft: () => {
+        if (getCaretPosition() === 0) {
+          focusPrevElement();
+          e.preventDefault();
+        }
+      },
+      ArrowRight: () => {
+        if (getCaretPosition() === text.length) {
+          focusNextElement();
+          e.preventDefault();
+        }
+      },
+      Enter: () => {
+        onSelectSuggestion(suggestions[i]);
+        e.preventDefault();
+      },
+    };
+    fns[e.key]?.();
+  };
+
+  return <span>
+    <span className="border-around-input">
+      <span className="editable" ref={ref} contentEditable="plaintext-only" onInput={onInput} onKeyDown={onKeyDown}
+      onFocus={() => setHaveFocus(true)}
+      onBlur={() => {
+        // hacky, but couldn't find another way:
+        // setTimeout(resetFocus, 0);
+        setHaveFocus(false);
+      } } style={{ height: 19 }}></span>
+      {
+        (haveFocus)
+        ? <Suggestions suggestions={suggestions} onSelect={onSelectSuggestion} i={i} setI={setI} />
+        : <></>
+      }
+    <span className="text-block suggest">{singleSuggestion}</span>
+    </span>
+  </span>;
+}
+
+function Suggestions({ suggestions, onSelect, i, setI }) {
+  return (suggestions.length > 0) ?
+    <div className="suggestions">
+      {suggestions.map(([name, dynamic], j) => <div key={`${j}_${name}`} className={i === j ? "selected" : ""} onClick={() => setI(j)} onDoubleClick={() => onSelect(suggestions[i])}>{name} :: <Type type={getType(dynamic)} /></div>)}
+    </div>
+    : <></>;
+}
\ No newline at end of file
diff --git a/src/Editor.css b/src/Type.css
similarity index 77%
rename from src/Editor.css
rename to src/Type.css
index 366386e..d11a299 100644
--- a/src/Editor.css
+++ b/src/Type.css
@@ -1,26 +1,3 @@
-.suggest {
-  color: #aaa;
-}
-.suggestions { 
-  position: absolute;
-  border: solid 1px lightgrey;
-  cursor: pointer;
-  max-height: calc(100vh - 48px);
-  overflow: scroll;
-}
-.selected {
-  background-color: darkseagreen;
-  color: white;
-}
-
-
-[contenteditable] {
-  outline: 0px solid transparent;
-}
-
-
-/* TYPES */
-
 .infix {
   margin-left: 1px;
   margin-right: 1px;
diff --git a/src/Type.tsx b/src/Type.tsx
new file mode 100644
index 0000000..db77e59
--- /dev/null
+++ b/src/Type.tsx
@@ -0,0 +1,46 @@
+import { getHumanReadableName, getSymbol, symbolDict, symbolDictIterator, symbolFunction, symbolList, symbolProduct, symbolSet, symbolSetIterator, symbolSum } from "dope2";
+
+import "./Type.css";
+
+export function Type({type}) {
+  const symbol = getSymbol(type);
+  switch (symbol) {
+    case symbolFunction:
+      return <BinaryType type={type} cssClass="functionType" infix="&rarr;" prefix="" suffix=""/>;
+    case symbolProduct:
+      return <BinaryType type={type} cssClass="productType" infix="&#10799;" prefix="" suffix=""/>;
+    case symbolSum:
+      return <BinaryType type={type} cssClass="sumType" infix="+" prefix="" suffix=""/>;
+    case symbolDict:
+      return <BinaryType type={type} cssClass="dictType" infix="&rArr;" prefix="{" suffix="}"/>;
+    case symbolSet:
+      return <UnaryType type={type} cssClass="setType" prefix="{" suffix="}" />;
+    case symbolList:
+      return <UnaryType type={type} cssClass="listType" prefix="[" suffix="]" />;
+    case symbolSetIterator:
+      return <UnaryType type={type} cssClass="setType iteratorType" prefix="{*" suffix="}" />;
+    case symbolDictIterator:
+      return <BinaryType type={type} cssClass="dictType iteratorType" infix="*&rArr;" prefix="{" suffix="}"/>;
+  
+      default:
+      return <div className="type">{getHumanReadableName(symbol)}</div>
+  }
+}
+
+function BinaryType({type, cssClass, infix, prefix, suffix}) {
+  return <div className={`type ${cssClass}`}>
+    {prefix}
+    <Type type={type.params[0](type)}/>
+    <span className="infix">{infix}</span>
+    <Type type={type.params[1](type)}/>
+    {suffix}
+  </div>
+}
+
+function UnaryType({type, cssClass, prefix, suffix}) {
+  return <div className={`type ${cssClass}`}>
+    {prefix}
+    <Type type={type.params[0](type)}/>
+    {suffix}
+  </div>
+}
\ No newline at end of file
diff --git a/src/main.tsx b/src/main.tsx
index bef5202..ee85237 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -1,7 +1,7 @@
 import { StrictMode } from 'react'
 import { createRoot } from 'react-dom/client'
+import { App } from './App.tsx'
 import './index.css'
-import App from './App.tsx'
 
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
diff --git a/src/util/dom_trickery.ts b/src/util/dom_trickery.ts
new file mode 100644
index 0000000..c474b7e
--- /dev/null
+++ b/src/util/dom_trickery.ts
@@ -0,0 +1,49 @@
+
+// If there is a caret anywhere in the document (user entering text), returns the position of the caret in the focused element
+export function getCaretPosition(): number | undefined {
+  const selection = window.getSelection();
+  if (selection) {
+    const range = selection.getRangeAt(0);
+    const clonedRange = range.cloneRange();
+    return clonedRange.startOffset;
+  }
+}
+
+// export function setCursorPosition(elem, pos) {
+//   const range = document.createRange();
+//   range.selectNode(elem);
+//   range.setStart(elem, pos);
+//   range.setEnd(elem, pos);
+//   const selection = window.getSelection();
+//   selection?.removeAllRanges();
+//   selection?.addRange(range);
+// }
+
+// Move caret all the way to the right in the currently focused element
+export function setRightMostCaretPosition(elem) {
+  const range = document.createRange();
+  range.selectNode(elem);
+  if (elem.lastChild) { // if no text is entered, there is no lastChild
+    range.setStart(elem.lastChild, elem.textContent.length);
+    range.setEnd(elem.lastChild, elem.textContent.length);
+    const selection = window.getSelection();
+    selection?.removeAllRanges();
+    selection?.addRange(range);
+  }
+}
+
+export function focusNextElement() {
+  const editable = Array.from<any>(document.querySelectorAll('[contenteditable]'));
+  const index = editable.indexOf(document.activeElement);
+  editable[index+1]?.focus();
+}
+
+export function focusPrevElement() {
+  const editable = Array.from<any>(document.querySelectorAll('[contenteditable]'));
+  const index = editable.indexOf(document.activeElement);
+  const prevElem = editable[index-1]
+  if (prevElem) {
+    prevElem.focus();
+    setRightMostCaretPosition(prevElem);
+  }
+}
\ No newline at end of file
diff --git a/src/util/extra.ts b/src/util/extra.ts
new file mode 100644
index 0000000..c8a39a4
--- /dev/null
+++ b/src/util/extra.ts
@@ -0,0 +1,10 @@
+export interface Dynamic {
+  i: any;
+  t: any;
+}
+
+export interface State2Props<T> {
+  state: T;
+  // setState: (callback: (state: T) => T) => void;
+  setState: (state: T) => void;
+}
diff --git a/src/fake_node_util.js b/src/util/fake_node_util.js
similarity index 100%
rename from src/fake_node_util.js
rename to src/util/fake_node_util.js
diff --git a/src/util/parse.ts b/src/util/parse.ts
new file mode 100644
index 0000000..fbd24f1
--- /dev/null
+++ b/src/util/parse.ts
@@ -0,0 +1,21 @@
+
+// Helpers...
+export function parseDouble(text: string): number | undefined {
+  if (text === '') {
+    return;
+  }
+  const num = Number(text);
+  if (Number.isNaN(num)) {
+    return;
+  }
+  return num;
+}
+export function parseInt(text: string): bigint | undefined {
+  if (text === '') {
+    return;
+  }
+  try {
+    return BigInt(text);
+  }
+  catch (e) { };
+}
diff --git a/vite.config.ts b/vite.config.ts
index 8d7ef44..4f72c3e 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -10,7 +10,7 @@ export default defineConfig({
   resolve: {
     alias: {
         // polyfills
-        "node:util": './src/fake_node_util.js',
+        "node:util": './src/util/fake_node_util.js',
     }
   }
 });