This is a RiveScript interpreter library written for the Go programming language. RiveScript is a scripting language for chatterbots, making it easy to write trigger/response pairs for building up a bot's intelligence.

This project is currently in Beta status. The API should be mostly stable but things might move around on you.

RiveScript is a scripting language for authoring chatbots. It has a very simple syntax and is designed to be easy to read and fast to write.

A simple example of what RiveScript looks like:

+ hello bot
- Hello human.

This matches a user's message of "hello bot" and would reply "Hello human." Or for a slightly more complicated example:

+ my name is *
* <formal> == <bot name> => <set name=<formal>>Wow, we have the same name!
* <get name> != undefined => <set name=<formal>>Did you change your name?
- <set name=<formal>>Nice to meet you, <get name>!

The official website for RiveScript is https://www.rivescript.com/

To test drive RiveScript in your web browser, try the RiveScript Playground.

• RiveScript Library: https://godoc.org/github.com/aichaos/rivescript-go
• RiveScript Stand-alone Interpreter: https://godoc.org/github.com/aichaos/rivescript-go/cmd/rivescript
• JavaScript Object Macros: https://godoc.org/github.com/aichaos/rivescript-go/lang/javascript
• RiveScript Parser: https://godoc.org/github.com/aichaos/rivescript-go/parser

Also check out the RiveScript Community Wiki for common design patterns and tips & tricks for RiveScript.

For the development library:

go get github.com/aichaos/rivescript-go

For the stand-alone rivescript binary for testing a bot:

go get github.com/aichaos/rivescript-go/cmd/rivescript

The distribution of RiveScript includes an interactive shell for testing your RiveScript bot. Run it with the path to a folder on disk that contains your RiveScript documents. Example:

# (Linux)
$ rivescript eg/brain

# (Windows)
> rivescript.exe eg/brain

See rivescript -help for options it accepts, including debug mode and UTF-8 mode.

When used as a library for writing your own chatbot, the synopsis is as follows:

package main

import (
    "fmt"
    "github.com/aichaos/rivescript-go"
)

func main() {
    // Create a new bot with the default settings.
    bot := rivescript.New(nil)

    // To enable UTF-8 mode, you'd have initialized the bot like:
    bot = rivescript.New(rivescript.WithUTF8())

    // Load a directory full of RiveScript documents (.rive files)
    err := bot.LoadDirectory("eg/brain")
    if err != nil {
      fmt.Printf("Error loading from directory: %s", err)
    }

    // Load an individual file.
    err = bot.LoadFile("./testsuite.rive")
    if err != nil {
      fmt.Printf("Error loading from file: %s", err)
    }

    // Sort the replies after loading them!
    bot.SortReplies()

    // Get a reply.
    reply, err := bot.Reply("local-user", "Hello, bot!")
    if err != nil {
      fmt.Printf("Error: %s\n", err)
    } else {
      fmt.Printf("The bot says: %s", reply)
    }
}

The constructor takes an optional Config struct. Here is a full example with all the supported options. You only need to provide keys that are different to the defaults.

bot := rivescript.New(&rivescript.Config{
    Debug: false,                 // Debug mode, off by default
    Strict: false,                // No strict syntax checking
    UTF8: false,                  // No UTF-8 support enabled by default
    Depth: 50,                    // Becomes default 50 if Depth is <= 0
    Seed: time.Now().UnixNano(),  // Random number seed (default is == 0)
    SessionManager: memory.New(), // Default in-memory session manager
})

For convenience, you can use a shortcut:

// A nil config uses all the defaults.
bot = rivescript.New(nil)

// WithUTF8 enables UTF-8 mode (other settings left as default).
bot = rivescript.New(rivescript.WithUTF8())

A common feature in many RiveScript implementations is the object macro, which enables you to write dynamic program code (in your favorite programming language) to add extra capabilities to your bot. For example, your bot could answer a question of "what is the weather like in $location" by running some code to look up their answer via a web API.

The Go version of RiveScript has support for object macros written in Go (at compile time of your application). It also has optional support for JavaScript object macros using the goja library.

Here is how to define a Go object macro:

bot.SetSubroutine(func(rs *rivescript.RiveScript, args []string) string {
    return "Hello world!"
})

Here is an example how to make JavaScript object macros available via the goja module:

package main

import (
    "fmt"
    "github.com/aichaos/rivescript-go"
    "github.com/aichaos/rivescript-go/lang/javascript"
)

func main() {
    // Initialize RiveScript first.
    bot := rivescript.New(rivescript.WithUTF8())

    // Add the JavaScript object macro handler.
    js := javascript.New(bot)
    bot.SetHandler("javascript", js)

    // You can access the goja VM and set your own global
    // variable or function bindings to be called from your
    // object macros.
    js.VM.Set("helloFunc", func(name string) string {
        return fmt.Sprintf("Hello, %s!", name)
    })

    // Load some RiveScript code. This example just tests the
    // JavaScript object macro support.
    err := bot.Stream(`
        > object add javascript
          let a = args[0];
          let b = args[1];
          return parseInt(a) + parseInt(b);
        < object

        > object fn javascript
          let result = helloFunc(args[0])
          return result
        < object

        + add # and #
        - <star1> + <star2> = <call>add <star1> <star2></call>

        + say hello *
        - <call>fn <star></call>
    `)
    if err != nil {
      fmt.Printf("Error loading RiveScript document: %s", err)
    }

    // Sort the replies after loading them!
    bot.SortReplies()

    // Get some replies!
    inputs := []string{"add 5 and 12", "say hello goja"}
    for _, message := range inputs {
      fmt.Printf("You said: %s\n", message)
        reply, err := bot.Reply("local-user", message)
        if err != nil {
          fmt.Printf("Error: %s\n", err)
        } else {
          fmt.Printf("The bot says: %s\n", reply)
        }
    }
}

UTF-8 support in RiveScript is considered an experimental feature. It is disabled by default.

By default (without UTF-8 mode on), triggers may only contain basic ASCII characters (no foreign characters), and the user's message is stripped of all characters except letters, numbers and spaces. This means that, for example, you can't capture a user's e-mail address in a RiveScript reply, because of the @ and . characters.

When UTF-8 mode is enabled, these restrictions are lifted. Triggers are only limited to not contain certain metacharacters like the backslash, and the user's message is only stripped of backslashes and HTML angled brackets (to protect from obvious XSS if you use RiveScript in a web application). Additionally, common punctuation characters are stripped out, with the default set being /[.,!?;:]/g. This can be overridden by providing a new regexp string literal to the RiveScript.SetUnicodePunctuation function. Example:

// Make a new bot with UTF-8 mode enabled.
bot := rivescript.New(rivescript.WithUTF8())

// Override the punctuation characters that get stripped
// from the user's message.
bot.SetUnicodePunctuation(`[.,!?;:]`);

The <star> tags in RiveScript will capture the user's "raw" input, so you can write replies to get the user's e-mail address or store foreign characters in their name.

I use a GNU Makefile to make building and running this module easier. The relevant commands are:

• make setup - run this after freshly cloning this repo. It runs the git submodule commands to pull down vendored dependencies.
• make build - this will build the front-end command from cmd/rivescript and place its binary into the bin/ directory. It builds a binary relevant to your current system, so on Linux this will create a Linux binary. It's also recommended to run this one at least once, because it will cache dependency packages and speed up subsequent builds and runs.
• make run - runs the front-end command and points it to the eg/brain folder as its RiveScript source.
• make fmt - runs gofmt -w on all the source files.
• make test - runs the unit tests.
• make clean - cleans up the .gopath, bin and dist directories.

The rivescript-go repo submodules the RiveScript Test Suite (rsts) project. If you didn't do a git clone --recursive for rivescript-go you can pull the submodule via the following commands:

git submodule init
git submodule update

Then make test (or go test) should show results from the tests run out of the rsts/ folder.

You can build a release for an individual platform by running a command like make linux/amd64. The valid build targets are currently as follows:

• Linux: linux/386 and linux/amd64
• Windows: windows/386 and windows/amd64
• MacOS: darwin/amd64

Run make release to automatically build releases for all supported platforms.

A directory for the release is created in dist/rivescript-$VERSION-$OS-$ARCH/ that contains the built binary, README.md, Changes.md and examples. You can inspect this directory afterwards; its contents are automatically tarred up (zip for Windows) and placed in the root of the git repo.

If you are cross-compiling for a different system, you may need to mess with permissions so that Go can download the standard library for the new target. Example:

% sudo mkdir /usr/lib/golang/pkg/windows_386
% chown your_user:your_user /usr/lib/golang/pkg/windows_386

• rivescript-go/parser - A standalone package for parsing RiveScript code and returning an "abstract syntax tree."
• rivescript-go/macro - Contains an interface for creating your own object macro handlers for foreign programming languages.
• rivescript-go/sessions - Contains the interface for user variable session managers as well as the default in-memory manager and the NullStore for testing. Other official session managers (e.g. Redis) are in here as well.

The MIT License (MIT)

Copyright (c) 2017 Noah Petherbridge

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.

The official RiveScript website, http://www.rivescript.com/