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A text calculator for natural language expressions with a vim-style TUI.

Try it online →

• Natural language expressions: 20% of 150, $100 in euros, 2 hours + 30 min
• Variables: tax = 15% then 100 + tax
• Unit conversions: Length, weight, time, temperature, data sizes
• Compound units: 5 m * 10 m = 50 m², 100 km / 2 h = 50 km/h
• Currency conversions: USD, EUR, GBP, JPY, CHF, CNY, CAD, AUD, INR, KRW, RUB, ILS, PLN, UAH + crypto (BTC, ETH, SOL, and more)
• Live exchange rates: Fetched automatically on startup
• Dual keybinding modes: Vim (modal) or Standard (direct input) - toggle with Shift+Tab
• Mouse support: Scroll with mouse wheel or trackpad
• File persistence: Auto-saves to config directory, supports custom files
• Syntax highlighting: Numbers, operators, variables, units, and currencies
• Comments: Lines starting with # or // are treated as comments
• Continuation: Start a line with an operator (+ 10, * 2) to continue from the previous result
• Wrap mode: Toggle text wrapping with bottom-aligned results
• Grouped totals: Currencies and units summed separately in footer (respects exchange rates)

brew tap nasedkinpv/tap
brew install numr

# Using yay
yay -S numr

# Using paru
paru -S numr

# Install from source
cargo install --path crates/numr-tui

# Or build from source
cargo build --release

# Binary will be available at target/release/numr

# Open default file (~/.config/numr/default.numr)
numr

# Open specific file
numr example.numr

# Single expression
numr-cli "20% of 150"

# Evaluate file
numr-cli -f example.numr

# Interactive REPL
numr-cli -i

# Pipe mode
echo "100 + 200" | numr-cli

Run numr as a backend for other tools (editors, launchers, scripts):

numr-cli --server

Send JSON-RPC 2.0 requests via stdin, receive responses via stdout:

echo '{"jsonrpc":"2.0","method":"eval","params":{"expr":"20% of 150"},"id":1}' | numr-cli --server
# {"jsonrpc":"2.0","result":{"type":"number","value":30.0,"display":"30"},"id":1}

Available methods:

The TUI supports two keybinding modes: Vim (default) and Standard. Press Shift+Tab to toggle between them.

Direct input like traditional editors - no modal switching required.

10 + 20           → 30
100 - 25          → 75
6 * 7             → 42
100 / 4           → 25
2 ^ 8             → 256

20% of 150        → 30
100 + 15%         → 115
$50 - 10%         → $45

price = $100
tax = 8%
price + tax       → $108

# This is a comment
// This is also a comment
Groceries         $45.00
# Comments are dimmed and ignored in calculations

$100              → $100
+ $50             → $150 (continues from previous)
* 2               → $300
- 10%             → $270
total = _         → $270 (_ or ANS references previous result)

sum(10, 20, 30)   → 60
avg(10, 20, 30)   → 20
min(5, 3, 8)      → 3
max(5, 3, 8)      → 8
sqrt(16)          → 4
abs(-5)           → 5
round(3.7)        → 4
floor(3.7)        → 3
ceil(3.2)         → 4

# Area from multiplication
5 m * 10 m        → 50 m²

# Speed from division
100 km / 2 h      → 50 km/h

# Distance from speed × time
50 kph * 2 h      → 100 km

# Unit conversions
50 kph in mps     → 13.89 m/s

# Mixed operations
25 km / 100 km    → 0.25 (dimensionless)

Compound unit aliases: kph (km/h), mph (mi/h), mps (m/s), m2 (m²), km2 (km²), ft2 (ft²)

km, m, cm, mm, mi/miles, ft/feet, in/inches

m²/m2, km²/km2, ft²/ft2, acre, hectare/ha

m/s/mps, km/h/kph, mph, knot

kg, g, mg, lb/lbs, oz, ton

L, mL, gal, m³/m3

months/mo, weeks/wk, days/d, hours/hr/h, minutes/min, seconds/sec/s

J, kJ, cal, kcal, kWh

W, kW

K/Kelvin, C/Celsius, F/Fahrenheit

TB, GB, MB, KB, bytes

Fiat: $/USD, €/EUR, £/GBP, ¥/JPY, CHF, CNY/RMB, CAD, AUD, ₹/INR, ₩/KRW, ₽/RUB, ₪/ILS, zł/PLN, ₴/UAH

Crypto: ₿/BTC, Ξ/ETH, ◎/SOL, ₮/USDT, USDC, BNB, XRP, ₳/ADA, Ð/DOGE, DOT, Ł/LTC, LINK, AVAX, MATIC, TON

graph TB
    subgraph Frontends
        TUI[numr-tui<br/>Ratatui Terminal UI]
        CLI[numr-cli<br/>Command Line]
    end

    subgraph Editor[numr-editor]
        Highlight[Syntax Highlighting]
    end

    subgraph Core[numr-core]
        Parser[Parser<br/>Pest PEG Grammar]
        AST[AST Builder]
        Eval[Evaluator]
        Types[Types<br/>Value, Currency, Unit]
        Cache[Rate Cache]
        Fetch[Fetch Module]
    end

    subgraph External APIs
        Fiat[open.er-api.com<br/>Fiat Rates]
        Crypto[CoinGecko API<br/>Crypto Prices]
    end

    TUI --> Highlight
    TUI --> Parser
    CLI --> Parser
    Highlight --> Types
    Parser --> AST
    AST --> Eval
    Eval --> Types
    Eval --> Cache
    TUI -.->|fetch on startup| Fetch
    CLI -.->|fetch if cache expired| Fetch
    Fetch -.-> Fiat
    Fetch -.-> Crypto
    Fetch -.-> Cache

numr/
├── crates/
│   ├── numr-core/     # Core evaluation engine (WASM-compatible)
│   │   ├── parser/    # Pest PEG grammar and AST builder
│   │   ├── eval/      # Expression evaluation with unit/currency handling
│   │   ├── types/     # Value, Currency, Unit registries
│   │   ├── cache/     # Exchange rate caching with BFS path finding
│   │   └── fetch/     # HTTP fetching (optional "fetch" feature)
│   ├── numr-editor/   # Syntax highlighting (WASM-compatible)
│   ├── numr-tui/      # Terminal UI (Ratatui) with vim modes
│   └── numr-cli/      # Command-line interface and REPL

The core library (numr-core) is UI-agnostic and can be embedded in CLI, TUI, GUI, or WASM contexts. The fetch feature flag enables HTTP fetching (adds reqwest dependency, not WASM-compatible).

Exchange rates are cached to ~/.config/numr/rates.json with 1-hour expiry. Both TUI and CLI share this cache:

• TUI: Fetches fresh rates on startup
• CLI: Fetches only if cache is expired

Rate sources:

• Fiat currencies: open.er-api.com (152 currencies, free)
• Cryptocurrency: CoinGecko (15 tokens, free)

• elephant-numr — Provider for Walker/Elephant launcher

MIT