https://github.com/venkatperi/coffee-ast-walk

Walk Coffeescript's AST nodes
https://github.com/venkatperi/coffee-ast-walk

Last synced: 2 months ago
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Walk Coffeescript's AST nodes

• Host: GitHub
• URL: https://github.com/venkatperi/coffee-ast-walk
• Owner: venkatperi
• Created: 2016-05-17T17:29:55.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2016-05-25T20:56:39.000Z (about 9 years ago)
• Last Synced: 2023-12-25T19:03:45.710Z (over 1 year ago)
• Language: CoffeeScript
• Homepage:
• Size: 32.2 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# coffee-ast-walk

Walk Coffeescript's AST nodes

[![Build Status](https://travis-ci.org/venkatperi/coffee-ast-walk.svg?branch=master)](https://travis-ci.org/venkatperi/coffee-ast-walk)

# Installation

Install with npm

```shell

npm install coffee-ast-walk --save

```

# Examples

Create a ast walker

```coffeescript

astwalk = require 'coffee-ast-walk'

root = coffee.nodes source

walk = astwalk(root)

```

## Dump Every Node

```coffeescript

walk.walk (x) ->

  console.log x

```

## AST Node Count

```coffeescript

walk.reduce 0, (x, acc) ->

	if @isAstNode then acc + 1 else acc

```

## Find the First Class

```coffeescript

walk.findFirstByType 'Class'

```

## Get Parent of Type

```coffeescript

klass = walk.findFirstByType 'Class'

# fire up another walker

astwalk(klass).findParent ( x ) -> x.__type is 'Assign'

```

# API

Class |  Summary

------| ------------

[Walk](#class-Walk) | Walk Coffeescript's AST nodes

### WalkCLASS 

Walk Coffeescript's AST nodes


  

    
Methods

  

  

  

    :: constructor( __id, __type )

    public

    instance

    Walk

  

  

    

      


  


__id A unique id (monotonically increasing count).

  


__type The type of AST node (node.constructor.name)

  

  

      
Create AST Walker

  
If init is set, astwalk will perform an initial

  walk over the AST tree and append a meta object as well as two

  properties to each AST node:

  
AST Node Meta Information

  
astwalk adds a property meta to Base which is the base class for

   Coffeescript AST node classes. meta provides meta-information

  about the node and in many cases, it rolls up information from

  child nodes which can ease navigation and manipulation of the AST.

  

      

    

  

  

  

    :: walk( [depth][, context] )

    public

    instance

    Walk

  

  

    

      


  


depth limits the walk up to depth levels from the current node (i.e. relative to the current node).

  


context Object is available to the visitor callback.

  

  

      
Performs a walk -- calls the visitor for every node.

  
About the Visitor: visitor(node)

  
The current node is passed ot the visitor. Additionaly,

  the following properties are available in the this context

   of the visitor callback:

  


  


@path The path to the current node as an array of strings.

  


@depth The depth of the current node.

  


@isRoot True if the node is the root node.

  


@isLeaf True of the node is a leaf node.

  


@id The id used to invoke the current node, also the last

    element of the path array.

  


@isAstNode True if the node is a coffeescript AST node, or a

  scalar (string etc).

  


@context An optional context, passed to walk.

  


@parent The node's parent (undefined for root node).

  

  
The visitor callback can invoke @abort() to terminate the walk early.

  
 Visitor Return Value: If a visitor returns an Object,

  the values from visiting the current AST node's child nodes are

  added to the object with the same key names as the original node.

  This can be viewed as a mapping operation on the AST tree (see example at

   the end).

  

      

    

  

  

  

    :: findAll( [depth], f )

    public

    instance

    Walk

  

  

    

      


  


depth Number limits the traversal depth

  


f Function is called with each node. The node is returned if f returns true.

  

  

      
Finds all nodes that satisfy the callback

  

      
  Returns

  


  
Returns array of Object ast nodes or .

  

  

    

  

  

  

    :: findFirst( [depth], f )

    public

    instance

    Walk

  

  

    

      


  


depth Number limits the traversal depth

  


f Function is called with each node. The node is returned if f returns true.

  

  

      
Finds the first node that satisfies the callback

  

      
  Returns

  


  
Returns Object, the ast node or .

  

  

    

  

  

  

    :: findByType( t[, depth] )

    public

    instance

    Walk

  

  

    

      


  


t String the node type to search for.

  


depth Number limits the traversal depth

  

  

      
Finds all nodes with the given CoffeeScript node type.

  

      
  Returns

  


  
Returns array of Object ast nodes or .

  

  

    

  

  

  

    :: findFirstByType( t[, depth] )

    public

    instance

    Walk

  

  

    

      


  


t String the node type to search for.

  


depth Number limits the traversal depth

  

  

      
Finds the first node with the given CoffeeScript node type.

  

      
  Returns

  


  
Returns Object ast node or .

  

  

    

  

  

  

    :: reduce(  )

    public

    instance

    Walk

  

  

    

      


  


acc The initial value of the accumulator

  


f Function called with each node: f(node, acc).

  

  

      
Performs a reduce operation on the AST tree

  
Updates an internal accumulator to the value returned by

  f(node, acc) and returns the final value of acc.

  

      
  Returns

  


  
Returns the final accumulator value.

  

  

    

  

  





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