Bobbin

A clean, readable scripting language for branching dialogue and interactive stories.
Built for game developers. Ships with first-class Godot support.

WARNING: Bobbin is in early development... You should expect:

• Some features may be missing or incomplete
• Documentation is sparse
• There may be breaking changes between releases
• The API is not yet stable

Example

extern player_name
extern gold
save met_merchant = false

Welcome to the Brass Lantern, {player_name}!

- Browse wares
    set met_merchant = true
    The merchant spreads out their goods.
    - Buy healing potion (10 gold)
        if gold >= 10
            temp price = 10
            You hand over {price} gold coins.
            if met_merchant
                Here's a 2 gold discount for a returning customer!
                Actually, you only owe {price - 2} gold.
        else
            You don't have enough gold.
    - Just looking
        No problem, take your time.
    Come back anytime!

- Ask about rumors
    The merchant leans in close...
    Heard there's treasure in the old ruins.

Farewell, {player_name}! You have {gold} gold remaining.

Features

• Writer-friendly syntax — No boilerplate, just dialogue and choices
• Smart variable scoping — save persists across sessions, temp lives for the scene, extern reads from your game
• Nested branching — Unlimited nesting depth with automatic gather points
• Conditional logic — if/elseif/else with full expression support
• Expressions everywhere — Arithmetic, comparison, and logical operators in assignments and interpolations
• String interpolation — Embed variables and expressions in dialogue with {variable} or {a + b}
• Rich error messages — Rust-quality diagnostics that point to exactly what went wrong
• Fast & lightweight — Rust-powered runtime, instant parsing
• Cross-platform — Linux, Windows, macOS, and WASM (web exports)

Godot

Installation

1. Download the latest release from GitHub Releases
2. Extract the addons/ folder into your Godot project root
3. Enable the plugin in Project → Project Settings → Plugins

Quick Start

# Create runtime with extern variables
var host_state = { "player_name": "Ada" }
var runtime = BobbinRuntime.from_string_with_host(script_content, host_state)

# Main dialogue loop
while runtime.has_more():
    runtime.advance()
    print(runtime.current_line())

    if runtime.is_waiting_for_choice():
        var choices = runtime.current_choices()
        for i in choices.size():
            print("  %d. %s" % [i + 1, choices[i]])
        runtime.select_choice(0)  # Pick first choice

What's Next

• Character/speaker management
• Localization support
• Event triggering/callbacks
• Visit tracking for choices

Contributing

See CONTRIBUTING.md for development setup and guidelines.