https://github.com/hackergrrl/behaviortree-sexp

A S-expression parser for behaviour trees.
https://github.com/hackergrrl/behaviortree-sexp

Last synced: 20 days ago
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A S-expression parser for behaviour trees.

• Host: GitHub
• URL: https://github.com/hackergrrl/behaviortree-sexp
• Owner: hackergrrl
• License: mit
• Created: 2015-04-26T04:00:29.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2015-04-26T04:36:03.000Z (over 9 years ago)
• Last Synced: 2024-10-28T06:00:21.568Z (23 days ago)
• Language: JavaScript
• Homepage:
• Size: 141 KB
• Stars: 5
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
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# behaviortree-sexp

Parses S-expressions to create ready-to-go

[`behaviourtree`](https://github.com/Calamari/BehaviorTree.js) behaviour trees.

# background

This module's purpose may not be obvious if you aren't already familiar with

both Behaviour Trees and the

[`behaviourtree`](https://github.com/Calamari/BehaviorTree.js) module.

Behaviour trees are a flexible tool for, amongst other things, video game AI.

For some reading on the subject, try [Tamas Jano's

introduction](http://obviam.net/index.php/game-ai-an-introduction-to-behavior-trees/).

In particular, this module allows you to specify behaviour trees as ubiquitous

[S-expressions](http://en.wikipedia.org/wiki/S-expression), which are then

transformed into `BehaviorTree` objects fully compatible with

[`behaviourtree`](https://github.com/Calamari/BehaviorTree.js).

# example

```

var btree = require('behaviortree')

var btree_sexp = require('behaviortree_sexp')

var expr = '(sequence (beep) (beep))'

btree.register('beep', new btree.Task({

  run: function(obj) {

    console.log('beep')

    this.success()

  }

}))

var tree = btsexp(expr)

tree.step()

```

outputs

```

beep

beep

```

# built-in nodes

## succeed

Always returns success.

```

(succeed)

```

## invert

Makes its successful node fail and its failed node succeed.

```

(invert (succeed))

```

## sequence

Processes nodes in sequence. Succeeds only if all nodes succeed. Equivalent to

logical AND.

```

(sequence (succeed) (invert succeed) (succeed))

```

This will only run the first two nodes.

## selector

Processes nodes in sequence. Succeeds and returns immediately as soon as one

node succeeds. Equivalent to logical OR.

```

(selector (invert succeed) (succeed) (succeed))

```

This will only run the first two nodes.

## random

Chooses a node at random.

```

(random (beep) (boop))

```

This will run exactly one of `beep` or `boop`.

## your own!

You can register your own nodes via `btree.register(name, task)` which will then

be available automatically in your S-expressions. See the above example.

# contribute

Please do! File an issue or pull request. Stay consistent with the

[`standard`](https://github.com/feross/standard).

# license

MIT