fix(calc-02): update stack labels for navigation and move modes

Canceling stack-top editing now pushes the original value back before
leaving edit mode, including Escape and ArrowDown handling.

.memory/project.md

@@ -1,7 +1,8 @@
 # State
 - Core engine: `src/rpn-calculator.js`
-- Reference demo: `samples/calc-02/` (portrait-first HP48GX layout, compact mode/constants popups; Const button comes before Mode in the display row)
+- Reference demo: `samples/calc-02/` (portrait-first HP48GX layout; calc-02 keyboard shortcuts are the reference; compact mode/constants popups; Const button comes before Mode in the display row)
 - Important UI behavior: mode button shows the current angle mode; keyboard focus stays on the hidden input on desktop; clipboard paste is supported
+- Note: keep scrolling behavior in mind for the calc-02 demo when changing the stack/UI layout
 - Public API: `push`, `pop`, `clear`, `swap`, `remove`, `edit`, `isValidIndex`, `input`, `command`, `getOperationsByCategory`, `getConstants`, `listConstants`, `setConstant`, `removeConstant`, `hasConstant`
 - Config: `maxSize`, `base`, `angleMode`, `enabledCommands`
 - Commands: arithmetic, stack, trigonometry, constants `pi` and `e`; arithmetic includes `root`; constants can be added or removed dynamically through the core API

.memory/state.md

@@ -1,9 +1,8 @@
 # State
 - Core engine: `src/rpn-calculator.js`
-- Active demo: `samples/calc-02/` portrait-only HP48GX layout; display-adjacent button row stays in 4 columns and now shares the same base button styling as the function keys
+- Default demo: `samples/dev/` classic browser demo; `samples/calc-02/` remains the portrait-first HP48GX-inspired reference
-- Mode button shows the current angle mode only; selecting a mode uses a popup menu
 - Public API: `push`, `pop`, `clear`, `swap`, `remove`, `edit`, `isValidIndex`, `input`, `command`, `getOperationsByCategory`, `getConstants`, `listConstants`, `setConstant`, `removeConstant`, `hasConstant`
 - Config: `maxSize`, `base`, `angleMode`, `enabledCommands`
-- Commands: arithmetic, stack, trigonometry, constants `pi`, `e`, `phi`, `g`, and `c`; arithmetic now includes `root` for y-th roots; constants can now be added or removed dynamically through the core API
+- Commands: arithmetic, stack, trigonometry, constants `pi`, `e`, `phi`, `g`, and `c`; arithmetic includes `root` with `y√x`, `yroot`, and `nroot` aliases; constants can be added or removed dynamically through the core API
-- Demo actions: keyboard focus is kept on the hidden input on desktop so typing keeps working; the keypad layout places Enter in the bottom-left, ± in the former Enter position, and Esc before Clear for safety; paste parses clipboard text as a number before pushing it to the stack; Ctrl+V is supported via the hidden input paste event; backspace is ignored when the stack is empty; operation errors are shown as an overlay bar on top of the calculator with a shorter timeout and darker red; the display button row uses a 4-column grid with a spacer cell to preserve alignment
+- Demo behavior: `samples/dev/` keeps hidden input focus on desktop and supports clipboard paste; `samples/calc-02/` uses compact mode/constants popups, a 4-column display-adjacent row, stack selection/move mode, and paste through the hidden input
 - Exports: browser `window.RpnCalculator`, CommonJS `module.exports`

README.md

@@ -1,15 +1,16 @@
 # RPN Virtual Calculator
 
-A browser-friendly RPN calculator built around a small, generic JavaScript API.
+A browser-friendly RPN calculator built around a small JavaScript API.
 
 ## Overview
 
 This project provides:
 
 - a reusable JavaScript RPN engine in `src/rpn-calculator.js`
-- browser demos in `samples/dev/` and `samples/calc-02/`
+- a classic browser demo in `samples/dev/`
-- a command system centralized in a single operation dictionary
+- a portrait-first HP48GX-inspired demo in `samples/calc-02/`
-- a small public API focused on stack operations and generic command dispatch
+- a centralized command system with aliases
+- a compact public API focused on stack operations, editing, and command dispatch
 
 The main class is `RpnCalculator`.
 
@@ -19,9 +20,6 @@ The main class is `RpnCalculator`.
 - `samples/dev/index.html`: browser demo entry point
 - `samples/dev/index.css`: demo styles
 - `samples/dev/index.js`: demo UI and keyboard logic
-- `samples/calc-01/index.html`: active browser demo entry point
-- `samples/calc-01/index.css`: demo styles
-- `samples/calc-01/index.js`: demo UI and keyboard logic
 - `samples/calc-02/index.html`: portrait-first HP48GX-style demo entry point
 - `samples/calc-02/index.css`: portrait-first demo styles
 - `samples/calc-02/index.js`: portrait-first HP48GX-style demo UI and keyboard logic
@@ -68,10 +66,10 @@ State exposed on instances:
 
 ```js README.md
 const calc = new RpnCalculator({
-  maxSize: 2048,
+	maxSize: 2048,
-  base: 10,
+	base: 10,
-  angleMode: 'deg',
+	angleMode: 'deg',
-  enabledCommands: ['add', 'sub', 'mul', 'div']
+	enabledCommands: ['add', 'sub', 'mul', 'div']
 });
 ```
 
@@ -88,6 +86,9 @@ Available constants:
 
 - `pi`
 - `e`
+- `phi`
+- `g`
+- `c`
 - plus any user-defined constants added through the engine API
 
 They can be used through `command(...)`:
@@ -194,10 +195,10 @@ console.log(calc.pop()); // 5
 ```html README.md
 <script src="./src/rpn-calculator.js"></script>
 <script>
-  const calc = new RpnCalculator({ angleMode: 'deg' });
+	const calc = new RpnCalculator({ angleMode: 'deg' });
-  calc.push(9);
+	calc.push(9);
-  calc.command('sqrt');
+	calc.command('sqrt');
-  console.log(calc.pop());
+	console.log(calc.pop());
 </script>
 ```
 
@@ -239,7 +240,7 @@ console.log(calc.pop()); // 0.5
 
 ## Demo
 
-The active demo lives in `samples/dev/`.
+The default demo lives in `samples/dev/`.
 
 Main UI features:
 
@@ -249,7 +250,7 @@ Main UI features:
 - angle mode selector for `deg`, `rad`, and `grad`
 - status pills for `inputValue` and `isEditing`
 - grouped panels for `Stack`, `Arithmetic`, `Trigonometry`, and `Constants`
-- error display area
+- keyboard-friendly hidden input on desktop
 
 ## Calc 02 demo
 
@@ -274,12 +275,15 @@ The current demo supports:
 - `Escape`
 - `ArrowUp`, `ArrowDown`, `ArrowRight`
 - `+`, `-`, `*`, `/`, `%`, `^`
-- `q`, `n`, `r`, `i`, `g`, `l`, `s`, `c`, `S`, `C`
+- `s`, `S`, `r`, `R`, `v`, `u`
-- `x`, `y`, `z`, `t`
+- `l`, `L`, `n`, `N`, `e`, `E`
+- `i`, `o`, `a`, `I`, `O`, `A`
 
 The demo also implements stack selection and stack-item move mode in its UI layer using the public calculator methods.
 It keeps the calculator screen focused and updates the visible stack window as the selection moves.
 
+Note: `calc-02` keyboard shortcuts are the reference for this project.
+
 ## Exports
 
 `RpnCalculator` is exposed in both environments:

samples/calc-02/index.css

@@ -32,6 +32,7 @@
 html, body {
 	margin: 0;
 	min-height: 100%;
+	overflow-y: hidden;
 }
 
 body {
@@ -51,25 +52,24 @@ body {
 
 .calculator {
 	width: 100%;
-	height: auto;
+	max-width: 460px;
-	display: grid;
+	height: 100vh;
+	max-height: 100vh;
 	padding: 8px;
+	display: grid;
+	grid-template-rows: auto auto minmax(0, 1fr);
+	gap: 8px;
 	border-radius: 8px;
 	background: var(--panel);
 	box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.08);
-	grid-template-columns: 1fr;
+	justify-content: stretch;
-	grid-template-rows: auto auto auto auto auto;
+	align-content: start;
-	row-gap: 6px;
+	overflow: hidden;
-	grid-template-areas:
-		"display"
-		"display-buttons"
-		"keypad"
-		"functions"
-		"trigo";
 }
 
 .display-block,
 .display-panel,
+.display-buttons-panel,
 .keypad-panel,
 .functions-panel,
 .trigo-panel {
@@ -79,15 +79,7 @@ body {
 	box-shadow: none;
 }
 
-.display-buttons-panel {
-	border-radius: 8px;
-	border: 1px solid rgba(255, 255, 255, 0.06);
-	background: rgba(6, 10, 16, 0.16);
-	box-shadow: none;
-}
-
 .display-block {
-	grid-area: display;
 	display: grid;
 	gap: 0;
 	align-self: start;
@@ -131,10 +123,7 @@ body {
 	padding-block: 0;
 }
 
-.stack-label {
+/* removed extra first-column styling */
-	text-align: right;
-	opacity: 0.78;
-}
 
 .stack-value {
 	min-height: 0;
@@ -145,11 +134,26 @@ body {
 	justify-self: end;
 	font-size: 20px;
 }
+
+.stack-value.is-editing {
+	letter-spacing: 0.02em;
+}
+
+
+.stack-cell.is-selected {
+	background: transparent;
+	border-radius: 6px;
+	outline: 2px solid rgba(31, 42, 18, 0.2);
+	outline-offset: -2px;
+}
+
+.stack-cell.is-moving {
+	background: rgba(31, 42, 18, 0.18);
+}
 .display-buttons-panel {
-	grid-area: display-buttons;
 	padding: 8px;
-	align-self: start;
 	min-height: 0;
+	background: rgba(6, 10, 16, 0.16);
 }
 
 .display-buttons-grid {
@@ -231,10 +235,22 @@ body {
 .functions-panel,
 .trigo-panel {
 	padding: 8px;
-	align-self: start;
 	min-height: 0;
 }
 
+.calculator > .display-block,
+.calculator > .display-buttons-panel,
+.calculator > .keypad-scroll-area {
+	justify-self: stretch;
+}
+
+.keypad-scroll-area {
+	min-height: 0;
+	overflow-y: auto;
+	scrollbar-width: thin;
+	scrollbar-color: rgba(46, 105, 135, 1);
+}
+
 .status-bar {
 	position: absolute;
 	top: 0;
@@ -291,7 +307,6 @@ button {
 	border: 1px solid rgba(14, 18, 25, 0.85);
 	border-radius: 8px;
 	padding: 8px 8px;
-
 	font: inherit;
 	font-weight: 700;
 	color: var(--btnText);
@@ -326,6 +341,7 @@ button:active {
 		opacity: 0.7;
 	}
 }
+
 .stack-copy-button {
 	padding: 4px;
 	min-width: 24px;
@@ -376,6 +392,37 @@ button:active {
 	outline-offset: 2px;
 }
 
+.stack-value.is-editing {
+	display: inline-flex;
+	align-items: center;
+	justify-content: flex-end;
+	gap: 0;
+}
+
+.edit-text {
+	display: inline-block;
+	white-space: pre;
+}
+
+.edit-caret {
+	display: inline-block;
+	width: 1px;
+	height: 1em;
+	margin: 0 0.12ch;
+	background: currentColor;
+	animation: caret-blink 1s steps(1, end) infinite;
+	transform: translateY(0.02em);
+}
+
+@keyframes caret-blink {
+	0%, 49% {
+		opacity: 1;
+	}
+	50%, 100% {
+		opacity: 0.15;
+	}
+}
+
 .key-default {
 	background: linear-gradient(180deg, var(--btnTop), var(--btnBottom));
 	color: #eef2f7;

samples/calc-02/index.html

@@ -4,49 +4,51 @@
 	<meta charset="utf-8">
 	<meta name="viewport" content="width=device-width, initial-scale=1">
 	<title>HP48GX RPN Calculator</title>
-	<link rel="stylesheet" href="./index.css">
+	<link rel="stylesheet" href="./index.css?ver=1">
 </head>
 <body>
 	<main class="app-shell">
-		<section class="calculator calculator-portrait" aria-label="HP48GX style RPN calculator">
+		<section class="calculator" aria-label="HP48GX style RPN calculator">
-			<div class="display-block">
+				<div class="display-block">
-				<div class="display-panel">
+					<div class="display-panel">
-					<div class="status-bar" id="statusLine" aria-live="polite"></div>
+						<div class="status-bar" id="statusLine" aria-live="polite"></div>
-					<div class="display-frame">
+						<div class="display-frame">
-						<div class="display-grid">
+							<div class="display-grid">
-							<div class="stack-cell"><span class="stack-label">T:</span><button type="button" class="stack-copy-button" data-copy-stack="T" aria-label="Copy T value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackT" class="stack-value"></span></div>
+								<div class="stack-cell"><span class="stack-label">T:</span><button type="button" class="stack-copy-button" data-copy-stack="T" aria-label="Copy T value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackT" class="stack-value"></span></div>
-							<div class="stack-cell"><span class="stack-label">Z:</span><button type="button" class="stack-copy-button" data-copy-stack="Z" aria-label="Copy Z value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackZ" class="stack-value"></span></div>
+								<div class="stack-cell"><span class="stack-label">Z:</span><button type="button" class="stack-copy-button" data-copy-stack="Z" aria-label="Copy Z value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackZ" class="stack-value"></span></div>
-							<div class="stack-cell"><span class="stack-label">Y:</span><button type="button" class="stack-copy-button" data-copy-stack="Y" aria-label="Copy Y value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackY" class="stack-value"></span></div>
+								<div class="stack-cell"><span class="stack-label">Y:</span><button type="button" class="stack-copy-button" data-copy-stack="Y" aria-label="Copy Y value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackY" class="stack-value"></span></div>
-							<div class="stack-cell"><span class="stack-label">X:</span><button type="button" class="stack-copy-button" data-copy-stack="X" aria-label="Copy X value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackX" class="stack-value"></span></div>
+								<div class="stack-cell"><span class="stack-label">X:</span><button type="button" class="stack-copy-button" data-copy-stack="X" aria-label="Copy X value"><svg viewBox="0 0 24 24" aria-hidden="true" focusable="false"><path d="M15.5 4h-7A2.5 2.5 0 0 0 6 6.5V8H5.5A1.5 1.5 0 0 0 4 9.5v8A2.5 2.5 0 0 0 6.5 20H13a1 1 0 0 0 1-1v-1.5H17.5A2.5 2.5 0 0 0 20 15V6.5A2.5 2.5 0 0 0 17.5 4h-2Zm.5 2h1.5a.5.5 0 0 1 .5.5V14a.5.5 0 0 1-.5.5H13V6.5A2.5 2.5 0 0 0 15.5 6Zm-1.5 12H6.5a.5.5 0 0 1-.5-.5v-8a.5.5 0 0 1 .5-.5h7.5V18Zm-1.5-8h-4V8.5A.5.5 0 0 1 9 8h4a.5.5 0 0 1 .5.5V10Z"/></svg></button><span id="stackX" class="stack-value"></span></div>
+							</div>
 						</div>
 					</div>
 				</div>
-			</div>
 
-			<div class="display-buttons-panel">
+				<div class="display-buttons-panel">
-				<div class="display-buttons-grid">
+					<div class="display-buttons-grid">
-					<button id="constButton" class="display-button">π</button>
+						<button id="constButton" class="display-button">π</button>
-					<button id="pasteButton" class="display-button"><span class="display-button-symbol paste-symbol">⎘</span></button>
+						<button id="pasteButton" class="display-button"><span class="display-button-symbol paste-symbol">⎘</span></button>
-					<button id="upButton" class="display-button"><span class="display-button-symbol arrow-symbol">↑</span></button>
+						<button id="upButton" class="display-button"><span class="display-button-symbol arrow-symbol">↑</span></button>
-					<button id="modeButton" class="display-button">Mode</button>
+						<button id="modeButton" class="display-button">Mode</button>
-					<div class="display-button-spacer"></div>
+						<div class="display-button-spacer"></div>
-					<button id="leftButton" class="display-button display-button-offset"><span class="display-button-symbol arrow-symbol">←</span></button>
+						<button id="leftButton" class="display-button display-button-offset"><span class="display-button-symbol arrow-symbol">←</span></button>
-					<button id="downButton" class="display-button"><span class="display-button-symbol arrow-symbol">↓</span></button>
+						<button id="downButton" class="display-button"><span class="display-button-symbol arrow-symbol">↓</span></button>
-					<button id="rightButton" class="display-button"><span class="display-button-symbol arrow-symbol">→</span></button>
+						<button id="rightButton" class="display-button"><span class="display-button-symbol arrow-symbol">→</span></button>
+					</div>
 				</div>
-			</div>
 
-			<div class="keypad-panel">
+			<div class="keypad-scroll-area">
-				<div class="keypad-grid" id="keypadGrid"></div>
+				<div class="keypad-panel">
-			</div>
+						<div class="keypad-grid" id="keypadGrid"></div>
+					</div>
 
-			<div class="functions-panel">
+					<div class="functions-panel">
-				<div class="functions-grid" id="functionsGrid"></div>
+						<div class="functions-grid" id="functionsGrid"></div>
-			</div>
+					</div>
 
-			<div class="trigo-panel">
+					<div class="trigo-panel">
-				<div class="trigo-grid" id="trigoGrid"></div>
+						<div class="trigo-grid" id="trigoGrid"></div>
-			</div>
+					</div>
+				</div>
 
 			<input id="hiddenInput" class="hidden-input" type="text" autocomplete="off" aria-hidden="true" tabindex="-1">
 		</section>

samples/calc-02/index.js

@@ -30,10 +30,10 @@ const calculatorEl = document.querySelector('.calculator');
 const statusLine = document.getElementById('statusLine');
 
 const keypadKeys = [
-	{ label: 'ENTER', action: 'enter', className: 'key-enter' },
-	{ label: '⎋', action: 'escape', className: 'key-escape' },
 	{ label: 'C', action: 'clear', className: 'key-danger' },
 	{ label: '⌫', action: 'backspace', className: 'key-danger' },
+	{ label: '⎋', action: 'escape', className: 'key-escape' },
+	{ label: '⏎', action: 'enter', className: 'key-enter' },
 	{ label: '7', input: '7', className: 'key-default' },
 	{ label: '8', input: '8', className: 'key-default' },
 	{ label: '9', input: '9', className: 'key-default' },
@@ -53,28 +53,28 @@ const keypadKeys = [
 ];
 
 const functionKeys = [
-	{ label: 'x²', action: 'sqr', className: 'key-default' },
+	{ label: 'x²', action: 'sqr', className: 'key-default', title: 's' },
-	{ label: 'yˣ', action: 'pow', className: 'key-default' },
+	{ label: '√x', action: 'sqrt', className: 'key-default', title: 'r' },
-	{ label: '1/x', action: 'recip', className: 'key-default' },
+	{ label: '1/x', action: 'recip', className: 'key-default', title: 'x' },
 	{ label: '%', action: 'mod', className: 'key-default' },
-	{ label: '√x', action: 'sqrt', className: 'key-default' },
+	{ label: 'yˣ', action: 'pow', className: 'key-default', title: 'S' },
-	{ label: 'y√x', action: 'root', className: 'key-default' },
+	{ label: 'y√x', action: 'root', className: 'key-default', title: 'R' },
-	{ label: '10ˣ', action: 'pow10', className: 'key-default' },
+	{ label: '10ˣ', action: 'pow10', className: 'key-default', title: 'd' },
 	{ label: '', spacer: true },
-	{ label: 'log', action: 'log', className: 'key-default' },
+	{ label: 'log', action: 'log', className: 'key-default', title: 'l / L' },
-	{ label: 'ln', action: 'ln', className: 'key-default' },
+	{ label: 'ln', action: 'ln', className: 'key-default', title: 'n / N' },
-	{ label: 'eˣ', action: 'exp', className: 'key-default' },
+	{ label: 'eˣ', action: 'exp', className: 'key-default', title: 'e / E' },
 	{ label: '', spacer: true },
 ];
 
 const trigoKeys = [
-	{ label: 'sin', action: 'sin', className: 'key-default' },
+	{ label: 'sin', action: 'sin', className: 'key-default', title: 'i' },
-	{ label: 'cos', action: 'cos', className: 'key-default' },
+	{ label: 'cos', action: 'cos', className: 'key-default', title: 'o' },
-	{ label: 'tan', action: 'tan', className: 'key-default' },
+	{ label: 'tan', action: 'tan', className: 'key-default', title: 'a' },
 	{ label: '', spacer: true },
-	{ label: 'asin', action: 'asin', className: 'key-default' },
+	{ label: 'asin', action: 'asin', className: 'key-default', title: 'I' },
-	{ label: 'acos', action: 'acos', className: 'key-default' },
+	{ label: 'acos', action: 'acos', className: 'key-default', title: 'O' },
-	{ label: 'atan', action: 'atan', className: 'key-default' },
+	{ label: 'atan', action: 'atan', className: 'key-default', title: 'A' },
 	{ label: '', spacer: true },
 ];
 
@@ -94,6 +94,11 @@ function focusInput() {
 }
 
 let statusTimer = null;
+let editCursor = 0;
+let editRestoreValue = null;
+let stackMode = 'normal';
+let stackSelection = 0;
+let stackMoveSnapshot = null;
 
 function setStatus(message, isError = false, timeoutMs = 1400) {
 	if (!statusLine) return;
@@ -118,27 +123,41 @@ function clearStatus() {
 	statusLine.classList.remove('is-error');
 }
 
-function normalizeStack() {
-	while (calc.stack.length > 4) {
-		calc.stack.shift();
-	}
-}
-
 function getStackLine(indexFromTop) {
 	return indexFromTop >= 0 && indexFromTop < calc.stack.length ? calc.stack[indexFromTop] : '';
 }
 
 function getStackDisplayValue(label) {
-	if (label === 'X') {
+	if (label === 'X' && calc.isEditing) {
-		return calc.isEditing ? calc.inputValue : (calc.formatNumber(getStackLine(0)) || '');
+		return calc.inputValue;
 	}
-	if (label === 'Y') {
+	const indexMap = { X: 0, Y: 1, Z: 2, T: 3 };
-		return calc.isEditing ? (calc.formatNumber(getStackLine(0)) || '') : (calc.formatNumber(getStackLine(1)) || '');
+	const indexFromTop = calc.isEditing ? Math.max(0, indexMap[label] - 1) : indexMap[label];
+	return calc.formatNumber(getStackLine(indexFromTop)) || '';
+}
+
+function getVisibleStackLabel(label) {
+	if (stackMode === 'navigation' || stackMode === 'move') {
+		const indexMap = { X: 0, Y: 1, Z: 2, T: 3 };
+		return String(indexMap[label]);
 	}
-	if (label === 'Z') {
+	return label;
-		return calc.isEditing ? (calc.formatNumber(getStackLine(1)) || '') : (calc.formatNumber(getStackLine(2)) || '');
+}
+
+function updateStackLabels() {
+	const stackLabels = ['T', 'Z', 'Y', 'X'];
+	for (const label of stackLabels) {
+		const stackCell = stackEls[label].parentElement;
+		if (!stackCell) continue;
+		const labelEl = stackCell.querySelector('.stack-label');
+		if (labelEl) {
+			labelEl.textContent = `${getVisibleStackLabel(label)}:`;
+		}
 	}
-	return calc.isEditing ? (calc.formatNumber(getStackLine(2)) || '') : (calc.formatNumber(getStackLine(3)) || '');
+}
+
+function stackModeToLabel(index) {
+	return ['X', 'Y', 'Z', 'T'][Math.max(0, Math.min(3, index))] ?? 'X';
 }
 
 function updateCopyButtons() {
@@ -152,40 +171,191 @@ function updateCopyButtons() {
 	}
 }
 
+function renderEditValue() {
+	const cursor = Math.max(0, Math.min(editCursor, calc.inputValue.length));
+	stackEls.X.innerHTML = `<span class="edit-text">${calc.inputValue.slice(0, cursor)}</span><span class="edit-caret" aria-hidden="true"></span><span class="edit-text">${calc.inputValue.slice(cursor)}</span>`;
+}
+
 function render() {
-	normalizeStack();
 	const isPortrait = window.matchMedia('(orientation: portrait)').matches || window.innerWidth <= 860;
 	calculatorEl?.classList.toggle('portrait', isPortrait);
 	calculatorEl?.classList.toggle('landscape', !isPortrait);
-	stackEls.X.textContent = getStackDisplayValue('X');
+	const stackLabels = ['T', 'Z', 'Y', 'X'];
-	stackEls.Y.textContent = getStackDisplayValue('Y');
+	for (const label of stackLabels) {
-	stackEls.Z.textContent = getStackDisplayValue('Z');
+		const isSelected = stackMode !== 'normal' && stackModeToLabel(stackSelection) === label;
-	stackEls.T.textContent = getStackDisplayValue('T');
+		const value = label === 'X' && calc.isEditing ? '' : getStackDisplayValue(label);
+		stackEls[label].textContent = value;
+		stackEls[label].classList.toggle('is-editing', label === 'X' && calc.isEditing);
+		stackEls[label].classList.toggle('is-caret-visible', label === 'X' && calc.isEditing);
+		stackEls[label].parentElement?.classList.toggle('is-selected', isSelected);
+		stackEls[label].parentElement?.classList.toggle('is-moving', stackMode === 'move' && stackModeToLabel(stackSelection) === label);
+	}
+	if (calc.isEditing) {
+		renderEditValue();
+	}
+	updateStackLabels();
 	updateCopyButtons();
 	modeButton.textContent = calc.angleMode;
 }
 
+function stopEditing(clearValue = false) {
+	if (clearValue) {
+		calc.inputValue = '';
+	}
+	calc.isEditing = false;
+	editCursor = 0;
+}
+
+function cancelEditing() {
+	if (editRestoreValue !== null) {
+		calc.push(editRestoreValue);
+	}
+	editRestoreValue = null;
+	stopEditing(true);
+}
+
+function enterNavigationMode() {
+	if (calc.isEditing) return;
+	stackMode = 'navigation';
+	stackSelection = 0;
+	stackMoveSnapshot = null;
+	render();
+}
+
+function exitStackMode() {
+	stackMode = 'normal';
+	stackSelection = 0;
+	stackMoveSnapshot = null;
+	render();
+}
+
+function moveNavigationSelection(delta) {
+	const maxIndex = Math.max(0, calc.stack.length - 1);
+	stackSelection = Math.max(0, Math.min(maxIndex, stackSelection + delta));
+	render();
+}
+
+function beginStackMove() {
+	stackMode = 'move';
+	stackMoveSnapshot = calc.stack.slice();
+	render();
+}
+
+function restoreStackMoveSnapshot() {
+	if (!stackMoveSnapshot) return;
+	calc.stack = stackMoveSnapshot.slice();
+	stackMoveSnapshot = null;
+	render();
+}
+
+function validateStackMove() {
+	stackMoveSnapshot = null;
+	stackMode = 'normal';
+	render();
+}
+
+function moveSelectedStackValue(delta) {
+	const index = stackSelection;
+	const target = Math.max(0, Math.min(calc.stack.length - 1, index + delta));
+	if (target === index) return;
+	const value = calc.stack.splice(index, 1)[0];
+	calc.stack.splice(target, 0, value);
+	stackSelection = target;
+	render();
+}
+
+function enterNavigationMode() {
+	if (calc.isEditing) return;
+	stackMode = 'navigation';
+	stackSelection = 0;
+	render();
+}
+
+function exitStackMode() {
+	stackMode = 'normal';
+	stackSelection = 0;
+	stackMoveSnapshot = null;
+	render();
+}
+
+function moveNavigationSelection(delta) {
+	const maxIndex = Math.max(0, calc.stack.length - 1);
+	stackSelection = Math.max(0, Math.min(maxIndex, stackSelection + delta));
+	render();
+}
+
+function beginStackMove() {
+	stackMode = 'move';
+	stackMoveSnapshot = calc.stack.slice();
+	render();
+}
+
+function restoreStackMoveSnapshot() {
+	if (!stackMoveSnapshot) return;
+	calc.stack = stackMoveSnapshot.slice();
+	stackMoveSnapshot = null;
+	render();
+}
+
+function validateStackMove() {
+	stackMoveSnapshot = null;
+	stackMode = 'normal';
+	render();
+}
+
+function moveSelectedStackValue(delta) {
+	const index = stackSelection;
+	const target = Math.max(0, Math.min(calc.stack.length - 1, index + delta));
+	if (target === index) return;
+	const value = calc.stack.splice(index, 1)[0];
+	calc.stack.splice(target, 0, value);
+	stackSelection = target;
+	render();
+}
+
+function moveEditCursor(delta) {
+	editCursor = Math.max(0, Math.min(calc.inputValue.length, editCursor + delta));
+}
+
 function pushEditingValueIfNeeded() {
 	if (!calc.isEditing) return;
 	if (calc.inputValue !== '') {
 		calc.push(calc.parseInputValue(calc.inputValue));
 	}
+	editRestoreValue = null;
 	calc.inputValue = '';
 	calc.isEditing = false;
+	editCursor = 0;
+}
+
+function startEditingFromStackTop() {
+	if (!calc.isValidIndex(0)) return false;
+	const value = calc.stack[0];
+	editRestoreValue = value;
+	calc.remove(0);
+	calc.isEditing = true;
+	calc.inputValue = calc.formatNumber(value);
+	editCursor = calc.inputValue.length;
+	return true;
 }
 
 function inputToX(value) {
 	if (!calc.isEditing) {
 		calc.isEditing = true;
 		calc.inputValue = '';
+		editCursor = 0;
 	}
 	if (value === 'Backspace') {
-		calc.inputValue = calc.inputValue.slice(0, -1);
+		if (editCursor > 0) {
+			calc.inputValue = `${calc.inputValue.slice(0, editCursor - 1)}${calc.inputValue.slice(editCursor)}`;
+			editCursor -= 1;
+		}
 	} else {
-		calc.inputValue += value;
+		calc.inputValue = `${calc.inputValue.slice(0, editCursor)}${value}${calc.inputValue.slice(editCursor)}`;
+		editCursor += value.length;
 	}
 	if (calc.inputValue === '') {
-		calc.isEditing = false;
+		stopEditing();
 	}
 }
 
@@ -217,11 +387,9 @@ function execute(name) {
 			}
 		} else if (name === 'clear') {
 			calc.clear();
-			calc.inputValue = '';
+			stopEditing(true);
-			calc.isEditing = false;
 		} else if (name === 'escape') {
-			calc.inputValue = '';
+			cancelEditing();
-			calc.isEditing = false;
 		} else if (name === 'backspace') {
 			if (calc.isEditing) {
 				inputToX('Backspace');
@@ -235,35 +403,26 @@ function execute(name) {
 			}
 		} else if (name === 'neg') {
 			if (calc.isEditing) {
-				calc.inputValue = calc.inputValue.startsWith('-') ? calc.inputValue.slice(1) : `-${calc.inputValue}`;
+				const hasSign = calc.inputValue.startsWith('-');
+				calc.inputValue = hasSign ? calc.inputValue.slice(1) : `-${calc.inputValue}`;
+				moveEditCursor(hasSign ? -1 : 1);
 			} else {
-				calc.push(calc.pop() * -1);
+				calc.command('neg');
 			}
-		} else if (name === 'pow10') {
-			pushEditingValueIfNeeded();
-			const exponent = calc.stack[0];
-			calc.remove(0);
-			calc.push(10);
-			calc.push(exponent);
-			calc.command('pow');
-		} else if (name === 'exp') {
-			pushEditingValueIfNeeded();
-			const exponent = calc.stack[0];
-			calc.remove(0);
-			calc.push(Math.E);
-			calc.push(exponent);
-			calc.command('pow');
 		} else {
 			pushEditingValueIfNeeded();
 			calc.command(name);
 		}
+		if (!calc.isEditing) {
+			editCursor = 0;
+		}
 		render();
 	} catch (error) {
 		setStatus(error?.message || 'Operation error', true);
 	}
 }
 
-function createKeyButton({ label, input, action, spacer, className }) {
+function createKeyButton({ label, input, action, spacer, className, title }) {
 	if (spacer) {
 		const div = document.createElement('div');
 		return div;
@@ -272,6 +431,7 @@ function createKeyButton({ label, input, action, spacer, className }) {
 	button.type = 'button';
 	button.textContent = label;
 	button.className = className;
+	if (title) button.title = title;
 	button.addEventListener('click', () => {
 		if (input) {
 			inputToX(input);
@@ -302,6 +462,53 @@ async function copyStackValue(label) {
 function handleKeyboard(event) {
 	if (event.defaultPrevented) return;
 	const key = event.key;
+	if (stackMode === 'navigation') {
+		if (key === 'ArrowUp') {
+			event.preventDefault();
+			moveNavigationSelection(1);
+			return;
+		}
+		if (key === 'ArrowDown') {
+			event.preventDefault();
+			moveNavigationSelection(-1);
+			return;
+		}
+		if (key === 'Escape' || key === 'ArrowLeft') {
+			event.preventDefault();
+			exitStackMode();
+			return;
+		}
+		if (key === 'Enter') {
+			event.preventDefault();
+			beginStackMove();
+			return;
+		}
+		return;
+	}
+	if (stackMode === 'move') {
+		if (key === 'ArrowUp') {
+			event.preventDefault();
+			moveSelectedStackValue(1);
+			return;
+		}
+		if (key === 'ArrowDown') {
+			event.preventDefault();
+			moveSelectedStackValue(-1);
+			return;
+		}
+		if (key === 'Escape') {
+			event.preventDefault();
+			restoreStackMoveSnapshot();
+			exitStackMode();
+			return;
+		}
+		if (key === 'Enter') {
+			event.preventDefault();
+			validateStackMove();
+			return;
+		}
+		return;
+	}
 	if (/^[0-9.]$/.test(key)) {
 		event.preventDefault();
 		inputToX(key);
@@ -319,16 +526,58 @@ function handleKeyboard(event) {
 		'/': 'div',
 		'%': 'mod',
 		'^': 'pow',
+		s: 'sqr',
+		S: 'pow',
+		r: 'sqrt',
+		R: 'root',
+		x: 'recip',
+		d: 'pow10',
+		l: 'log',
+		L: 'log',
+		n: 'ln',
+		N: 'ln',
+		e: 'exp',
+		E: 'exp',
+		i: 'sin',
+		o: 'cos',
+		a: 'tan',
+		I: 'asin',
+		O: 'acos',
+		A: 'atan',
 	};
-	const arrowMap = {
+	if (key === 'ArrowLeft') {
-		ArrowUp: upButton,
-		ArrowDown: downButton,
-		ArrowLeft: leftButton,
-		ArrowRight: rightButton,
-	};
-	if (arrowMap[key]) {
 		event.preventDefault();
-		arrowMap[key].click();
+		if (calc.isEditing) {
+			moveEditCursor(-1);
+			render();
+			return;
+		}
+		leftButton.click();
+		return;
+	}
+	if (key === 'ArrowRight') {
+		event.preventDefault();
+		if (calc.isEditing) {
+			moveEditCursor(1);
+			render();
+			return;
+		}
+		rightButton.click();
+		return;
+	}
+	if (key === 'ArrowUp') {
+		event.preventDefault();
+		upButton.click();
+		return;
+	}
+	if (key === 'ArrowDown') {
+		event.preventDefault();
+		if (calc.isEditing) {
+			cancelEditing();
+			render();
+			return;
+		}
+		downButton.click();
 		return;
 	}
 	if (map[key]) {
@@ -427,14 +676,19 @@ hiddenInput.addEventListener('paste', (event) => {
 	pasteTextIntoStack(text);
 });
 
-upButton.addEventListener('click', () => {});
+upButton.addEventListener('click', () => {
+	if (!calc.isEditing && stackMode === 'normal') {
+		enterNavigationMode();
+		focusInput();
+	}
+});
 
 const constantLabels = {
 	pi: 'π',
 	e: 'e',
 	phi: 'φ',
 	g: 'g',
-	c: 'c',
+	c: 'C',
 };
 const constantOrder = ['pi', 'e', 'phi', 'g', 'c'];
 
@@ -473,19 +727,34 @@ constButton.addEventListener('click', (event) => {
 	toggleConstMenu();
 });
 
-leftButton.addEventListener('click', () => {});
+leftButton.addEventListener('click', () => {
+	if (calc.isEditing) {
+		moveEditCursor(-1);
+		render();
+		focusInput();
+		return;
+	}
+	if (stackMode === 'navigation') {
+		exitStackMode();
+		focusInput();
+	}
+});
 downButton.addEventListener('click', () => {
-	if (!calc.isEditing && calc.isValidIndex(0)) {
+	if (!calc.isEditing && startEditingFromStackTop()) {
-		const value = calc.stack[0];
-		calc.remove(0);
-		calc.isEditing = true;
-		calc.inputValue = calc.formatNumber(value);
 		render();
 		focusInput();
 	}
 });
 
+
+
 rightButton.addEventListener('click', () => {
+	if (calc.isEditing) {
+		moveEditCursor(1);
+		render();
+		focusInput();
+		return;
+	}
 	execute('swap');
 });
 

samples/calc-02/visual-portrait.md

@@ -24,11 +24,11 @@
 
 ```
 ┌──────────── Keypad ─────────────┐
-| +/- | Clear | Esc   | backspace |
+| Clear | Backspace | Esc | Enter |
-| 7   | 8     | 9     | /         |
+| 7     | 8         | 9   | /     |
-| 4   | 5     | 6     | *         |
+| 4     | 5         | 6   | *     |
-| 1   | 2     | 3     | -         |
+| 1     | 2         | 3   | -     |
-| 0   | .     | Enter | +         |
+| 0     | .         | +/- | +     |
 └─────────────────────────────────┘
 ```
 
@@ -36,9 +36,9 @@
 
 ```
 ┌──────────── Functions ──────────┐
-| x^2  | y^x   | 1/x   | %        |
+| x^2  | √x    | 1/x   | %        |
-| √x   | y√x   | 10^x  |          |
+| y^x  | y√x   | 10^x  |          |
-| log  | ln    |       |          |
+| log  | ln    | e^x   |          |
 └─────────────────────────────────┘
 ```
 

src/rpn-calculator.js

@@ -49,6 +49,18 @@ class RpnCalculator {
       aliases: ['^', 'y^x'],
       execute: (calc, a, b) => Math.pow(a, b),
     },
+    pow10: {
+      category: 'Arithmetic',
+      argCount: 1,
+      aliases: ['10^x'],
+      execute: (calc, a) => Math.pow(10, a),
+    },
+    exp: {
+      category: 'Arithmetic',
+      argCount: 1,
+      aliases: ['e^x'],
+      execute: (calc, a) => Math.exp(a),
+    },
     root: {
       category: 'Arithmetic',
       argCount: 2,
@@ -195,7 +207,7 @@ class RpnCalculator {
   static getOperationsByCategory() {
     return {
       Stack: ['dup', 'drop', 'swap', 'clear', 'enter'],
-      Arithmetic: ['add', 'sub', 'mul', 'div', 'mod', 'pow', 'root', 'sqr', 'neg', 'sqrt', 'recip', 'log', 'ln'],
+      Arithmetic: ['add', 'sub', 'mul', 'div', 'mod', 'pow', 'pow10', 'exp', 'root', 'sqr', 'neg', 'sqrt', 'recip', 'log', 'ln'],
       Trigonometry: ['sin', 'cos', 'tan', 'asin', 'acos', 'atan'],
     };
   }