ink

Ink is inkle's scripting language for writing interactive narrative, both for text-centric games as well as more graphical games that contain highly branching stories. It's designed to be easy to learn, but with powerful enough features to allow an advanced level of structuring.

Here's a taster from the tutorial.

- I looked at Monsieur Fogg 
*   ... and I could contain myself no longer.
    'What is the purpose of our journey, Monsieur?'
    'A wager,' he replied.
    * *     'A wager!'[] I returned.
            He nodded. 
            * * *   'But surely that is foolishness!'
            * * *  'A most serious matter then!'
            - - -   He nodded again.
            * * *   'But can we win?'
                    'That is what we will endeavour to find out,' he answered.
            * * *   'A modest wager, I trust?'
                    'Twenty thousand pounds,' he replied, quite flatly.
            * * *   I asked nothing further of him then[.], and after a final, polite cough, he offered nothing more to me. <>
    * *     'Ah[.'],' I replied, uncertain what I thought.
    - -     After that, <>
*   ... but I said nothing[] and <> 
- we passed the day in silence.
- -> END

Broadly, the engine is made up of two components:

inklecate is the command-line compiler for ink. It takes one or more text files with an .ink extension, and produces a .json file. It can also be used in play mode, for testing a story on the command line.
The ink runtime engine is a C# library that can be used within Unity or other C# environment.

Warning: ink is in alpha. Features may change, bugs may be encountered. We're yet to complete a project with this major rewrite of ink - it's a work in progress!

Getting started

Writing

Warning: Since the engine is in alpha, it hasn't been neatly packaged up for non-technical writers. Right now, you need basic knowledge of the command line to try out your stories.

Download the latest version of inklecate (or build it yourself, see below.)
Create a text file called myStory.ink, containing the text Hello, world!.
On the command line, run the following:

Mac: ./inklecate -p myStory.ink

Windows: inklecate.exe -p myStory.ink

The -p option uses play mode so that you can see the result immediately.

Optionally, you may want to install inklecate at a system level (e.g. on Mac copy to /usr/local/bin).
Follow the tutorial: Writing with Ink.

Integrating into your game

We currently have a C# runtime DLL ink-engine.dll, for example for use in Unity, and you'll also need the included Newtonsoft.Json.dll. It has a very simple API, so is easy integrate. It's not designed as an end-to-end narrative game engine. Rather, it's designed to be flexible, so that it can slot into your own game and UI with ease. Here's a taster, and is all you need to get started:

using Ink.Runtime;

// 1) Load story
_story = Story.CreateWithJson(sourceJsonString);

// 2) Game content, line by line
while(_story.canContinue)
    Debug.Log(story.Continue());

// 3) Display story.currentChoices list, allow player to choose one
Debug.Log(_story.currentChoices[0].choiceText);
_story.ChooseChoiceIndex(0);

// 4) Back to 2
...

For information on getting started, see Running Your Ink.

Building

Requirements

Windows:

Visual Studio (e.g. Community edition), Xamarin, or Unity's own version of MonoDevelop.

Mac:

Xamarin, or Unity's own version of MonoDevelop

Build

Load up the solution file - ink.sln.
Select the Release configuration and choose Build -> Build All (or Build Solution in Visual Studio).
The compiler binary should be built in inklecate/bin/Release (or x86), while the runtime engine DLL will be built in ink-engine-dll/bin/Release/ink-engine.dll

Note that the executable requires Mono on Mac or .NET on Windows. On Windows this isn't a problem since it ships with .NET, but on Mac you need Xamarin for Mono. The build_release.command file in the repo is a Mac script that will bundle up both Mac and Windows versions, and the Mac version will be bundled with the Mono runtime so that the end user doesn't need Xamarin/Mono installed.

The development of ink

How to contribute

We’d of course appreciate any bug fixes you might find! Also see the roadmap below for future planned features and optimisations that you might be able to help out with.

Create a GitHub issue if you want to start a discussion or request a feature. (Is this the best place for community discussion? We're pretty new to open source!) Or if you want to get in touch with us directly, email us.

We also have a public room in HipChat where you may find someone to help you:

In terms of related projects outside of the scope of this repo, we'd love to see the following since we don't have time to do it ourselves right now, and we think it would substantially help the community:

A more friendly install-edit-play flow for writers. For example, a downloadable GUI-based app with an editor pane on the left and a play pane on the right. Bonus points if the play pane automatically reloads the state of the story as you type!
Implementations of the runtime engine in other languages - for example JavaScript, so that stories can be run on the web. (Note that although we'd be excited to see that right now, we'd probably recommend that you don't embark on such a project just yet, since the runtime may still change substantially, so it could create unnecessary maintenance work.)
Unity template project to demonstrate how to set up a particular style of game.

Roadmap

Internally we've been thinking about the following. We can't guarantee we'll implement them any time soon though, or indeed at all!

Definitely coming

Save state from runtime
Punctuation and whitespace cleaner. Although the ink engine does the best it can at fixing various issues such including the right amount of whitespace, there are certain things that are hard or impossible to deal with, due to the text being inherently interactive and unpredictable. For Sorcery! and 80 Days we had a cleaning function which tidied up spacing and punctuation, and we intend to do the same with this latest version of the ink engine. A similar feature exists in HTML due to the inclusion of markup within text - for example, multiple spaces are collapsed down into one.
Improve succinctness of JSON representation - it’s currently much larger than it needs to be. Big problem when you have 10MB+ of source ink, as we've had on past games.
Tighten implementation to prevent certain "features" that aren't intentional (a wide class of bugs). For example, we currently allow content on the same line after the closing brace of a multi-line piece of logic.
Other bug fixes!

Probably coming

A scheme to split up the monolithic JSON output into smaller files that can be loaded on the fly in the runtime. This was necessary on Sorcery! and 80 Days as the quantity of content increased substantially, and we were running our games on low-end iOS devices at the time.
- Our implementation for the previous version of ink was to have two files: one huge text file with lots of JSON snippets that never got loaded in one go, and an index file, which contained byte offsets and lengths for all the compiled knots in the game. This worked pretty well, although it meant that the compiled JSON was still in one huge file.
- A possible alternative we could consider for ink2 is to (optionally?) be able to have a one-to-one mapping between source .ink files and output .json files, so that the size and arrangement is predictable and controllable.
Some kind of enum / flag system. Design yet to be determined.
General refactoring and improvements to code structure and optimisation of the compiler.
Structured JSON-like data objects within ink format. Exact design still to be determined, but goals are for it to be a superset of JSON, so that it’s compatible, but can be simpler (a bit like YAML, though not YAML for various reasons). Would allow more complex hierarchical game state to be stored within the ink engine.

To investigate

Consider changing multi-bullet weave indentation to Python-style whitespace indentation. This would be a huge syntax-breaking change, but we'd welcome a discussion and/or an experimental implementation.
Plugin architecture, to allow you to extract information from the ink while it's being compiled. Currently there's a basic example in the codebase, but it currently has to be built directly into the compiler, rather than via DLLs.
Audio and localisation. Difficult problems that need some thought.

Architectural overview

See the architectural overview documentation for information about the pipeline of the ink engine, and a birds-eye view of the project's code structure.

License

ink is released under the MIT license. Although we don't require attribution, we'd love to know if you decide to use ink a project! Let us know on Twitter or by email.

Newtonsoft's Json.NET is included, and also has the MIT License.

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.