simple-squiggle

A restricted subset of Squiggle
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README.md (4865B)

      1 ### Estraverse [![Build Status](https://secure.travis-ci.org/estools/estraverse.svg)](http://travis-ci.org/estools/estraverse)
      2 
      3 Estraverse ([estraverse](http://github.com/estools/estraverse)) is
      4 [ECMAScript](http://www.ecma-international.org/publications/standards/Ecma-262.htm)
      5 traversal functions from [esmangle project](http://github.com/estools/esmangle).
      6 
      7 ### Documentation
      8 
      9 You can find usage docs at [wiki page](https://github.com/estools/estraverse/wiki/Usage).
     10 
     11 ### Example Usage
     12 
     13 The following code will output all variables declared at the root of a file.
     14 
     15 ```javascript
     16 estraverse.traverse(ast, {
     17     enter: function (node, parent) {
     18         if (node.type == 'FunctionExpression' || node.type == 'FunctionDeclaration')
     19             return estraverse.VisitorOption.Skip;
     20     },
     21     leave: function (node, parent) {
     22         if (node.type == 'VariableDeclarator')
     23           console.log(node.id.name);
     24     }
     25 });
     26 ```
     27 
     28 We can use `this.skip`, `this.remove` and `this.break` functions instead of using Skip, Remove and Break.
     29 
     30 ```javascript
     31 estraverse.traverse(ast, {
     32     enter: function (node) {
     33         this.break();
     34     }
     35 });
     36 ```
     37 
     38 And estraverse provides `estraverse.replace` function. When returning node from `enter`/`leave`, current node is replaced with it.
     39 
     40 ```javascript
     41 result = estraverse.replace(tree, {
     42     enter: function (node) {
     43         // Replace it with replaced.
     44         if (node.type === 'Literal')
     45             return replaced;
     46     }
     47 });
     48 ```
     49 
     50 By passing `visitor.keys` mapping, we can extend estraverse traversing functionality.
     51 
     52 ```javascript
     53 // This tree contains a user-defined `TestExpression` node.
     54 var tree = {
     55     type: 'TestExpression',
     56 
     57     // This 'argument' is the property containing the other **node**.
     58     argument: {
     59         type: 'Literal',
     60         value: 20
     61     },
     62 
     63     // This 'extended' is the property not containing the other **node**.
     64     extended: true
     65 };
     66 estraverse.traverse(tree, {
     67     enter: function (node) { },
     68 
     69     // Extending the existing traversing rules.
     70     keys: {
     71         // TargetNodeName: [ 'keys', 'containing', 'the', 'other', '**node**' ]
     72         TestExpression: ['argument']
     73     }
     74 });
     75 ```
     76 
     77 By passing `visitor.fallback` option, we can control the behavior when encountering unknown nodes.
     78 
     79 ```javascript
     80 // This tree contains a user-defined `TestExpression` node.
     81 var tree = {
     82     type: 'TestExpression',
     83 
     84     // This 'argument' is the property containing the other **node**.
     85     argument: {
     86         type: 'Literal',
     87         value: 20
     88     },
     89 
     90     // This 'extended' is the property not containing the other **node**.
     91     extended: true
     92 };
     93 estraverse.traverse(tree, {
     94     enter: function (node) { },
     95 
     96     // Iterating the child **nodes** of unknown nodes.
     97     fallback: 'iteration'
     98 });
     99 ```
    100 
    101 When `visitor.fallback` is a function, we can determine which keys to visit on each node.
    102 
    103 ```javascript
    104 // This tree contains a user-defined `TestExpression` node.
    105 var tree = {
    106     type: 'TestExpression',
    107 
    108     // This 'argument' is the property containing the other **node**.
    109     argument: {
    110         type: 'Literal',
    111         value: 20
    112     },
    113 
    114     // This 'extended' is the property not containing the other **node**.
    115     extended: true
    116 };
    117 estraverse.traverse(tree, {
    118     enter: function (node) { },
    119 
    120     // Skip the `argument` property of each node
    121     fallback: function(node) {
    122         return Object.keys(node).filter(function(key) {
    123             return key !== 'argument';
    124         });
    125     }
    126 });
    127 ```
    128 
    129 ### License
    130 
    131 Copyright (C) 2012-2016 [Yusuke Suzuki](http://github.com/Constellation)
    132  (twitter: [@Constellation](http://twitter.com/Constellation)) and other contributors.
    133 
    134 Redistribution and use in source and binary forms, with or without
    135 modification, are permitted provided that the following conditions are met:
    136 
    137   * Redistributions of source code must retain the above copyright
    138     notice, this list of conditions and the following disclaimer.
    139 
    140   * Redistributions in binary form must reproduce the above copyright
    141     notice, this list of conditions and the following disclaimer in the
    142     documentation and/or other materials provided with the distribution.
    143 
    144 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    145 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    146 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    147 ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
    148 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    149 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
    150 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    151 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    152 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    153 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.