# RPN Virtual Calculator

A browser-friendly RPN calculator implemented as a single JavaScript class, with a simple API and an example HTML interface.

## Overview

The project includes:

- `rpn-calculator.js`: calculator engine
- `rpn-example.html`: browser demo

## Highlights

- Self-contained JavaScript class
- Configurable stack size (`maxSize`, default: 2048)
- Configurable numeric base (`base`, default: 10)
- Configurable angle mode (`angleMode`, default: `deg`)
- Optional command enabling via `enabledCommands`
- Generic public API centered on `push`, `pop`, `clear`, `swap`, `remove`, `edit`, `isValidIndex`, `input`, and `command`
- `inputValue` stays a string to keep hexadecimal input possible later
- `isEditing` tracks typed input mode
- Operations are centralized with `argCount`, category, and aliases
- Categories are limited to `Stack`, `Arithmetic`, and `Trigonometry`
- Clear domain errors for invalid inputs
- Degree-based trig demo in the example HTML

## Quick start

### In the browser

```html
<script src="rpn-calculator.js"></script>
<script>
  const calc = new RpnCalculator();
  calc.input('1');
  calc.input('2');
  calc.command('enter');
  calc.command('add');
  console.log(calc.stack);
</script>
```

### With options

```js
const calc = new RpnCalculator({
  maxSize: 1024,
  base: 10,
  angleMode: 'deg',
  enabledCommands: ['add', 'sub', 'mul', 'div', 'enter', 'clear'],
});
```

## Public API

### Properties

- `stack`: current stack, with the top item at index `0`
- `inputValue`: input text as a string
- `isEditing`: whether input is currently being edited

### Generic methods

- `push(value)`
- `pop()`
- `clear()`
- `swap(index1, index2)`
- `remove(index)`
- `edit(index)`
- `isValidIndex(index)`
- `input(command)`
- `command(name, ...args)`

## Supported commands

### Stack

- `enter`
- `dup`
- `drop`
- `swap`
- `clear`

### Arithmetic

- `add` / `+`
- `sub` / `-`
- `mul` / `*`
- `div` / `/`
- `mod` / `%`
- `pow` / `^` / `y^x`
- `sqr`
- `neg`
- `sqrt`
- `recip` / `1/x`
- `log`
- `ln`

### Trigonometry

- `sin`
- `cos`
- `tan`
- `asin`
- `acos`
- `atan`

## Important behavior

- `%` behaves as the RPN percentage operator: `a b % => (a * b) / 100`
- `sqrt`, `asin`, `acos`, `log`, and `ln` throw clear errors for invalid inputs
- `log` uses `Math.log10`
- `ln` uses `Math.log`
- `sin`, `cos`, and `tan` convert degrees to radians in the default demo
- `asin`, `acos`, and `atan` return degrees in `deg` mode

## Example HTML

The example UI groups buttons into `Stack`, `Arithmetic`, and `Trigonometry` sections, and calls `command(...)` to execute operations.

## License

To be completed according to your project.