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A small, fast, JavaScript-based JavaScript parser based on acorn
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A fast JavaScript parser in JavaScript. Based on acorn


overture.parse(inputString[, options]);


Here are the options and comments from inside the parser.

Items marked 'X' are not currently implemented.

var defaultOptions =  
    // `ecmaVersion` indicates the ECMAScript version to parse. Must  
    // be either 3 or 5. This  
    // influences support for strict mode, the set of reserved words, and  
    // support for getters and setter.  
    ecmaVersion: 5,  

    // Turn on `strictSemicolons` to prevent the parser from doing  
    // automatic semicolon insertion.  
    strictSemicolons: false,  

    // When `allowTrailingCommas` is false, the parser will not allow  
    // trailing commas in array and object literals.  
    allowTrailingCommas: true,  

    // By default, reserved words are not enforced. Enable  
    // `forbidReserved` to enforce them.  
    forbidReserved: false,  

    // When `locations` is on, `loc` properties holding objects with  
    // `start` and `end` properties in `{line, column}` form (with  
    // line being 1-based and column 0-based) will be attached to the  
    // nodes.  
    locations: false,  

    // A function can be passed as `onComment` option, which will  
    // cause Overture to call that function with `(block, text, start,  
    // end)` parameters whenever a comment is skipped. `block` is a  
    // boolean indicating whether this is a block (`/* */`) comment,  
    // `text` is the content of the comment, and `start` and `end` are  
    // character offsets that denote the start and end of the comment.  
    // When the `locations` option is on, two more parameters are  
    // passed, the full `{line, column}` locations of the start and  
    // end of the comments.  
X   onComment: null,  

    // Nodes have their start and end characters offsets recorded in  
    // `start` and `end` properties (directly on the node, rather than  
    // the `loc` object, which holds line/column data. To also add a  
    // [semi-standardized][range] `range` property holding a `[start,  
    // end]` array with the same numbers, set the `ranges` option to  
    // `true`.  
    // [range]:  
X   ranges: false,  

    // It is possible to parse multiple files into a single AST by  
    // passing the tree produced by parsing the first file as  
    // `program` option in subsequent parses. This will add the  
    // toplevel forms of the parsed file to the `Program` (top) node  
    // of an existing parse tree.  
    program: null,  

    // When `location` is on, you can pass this to record the source  
    // file in every node's `loc` object.  
    sourceFile: null  



This is the main file (and the only one you need to use)


Generates an AST which contains start and end location data.


Doesn't generate a syntax tree, it's an experiment to compare parsing performance to zeparser2 (

When I last tried it, there were performance issues with esprimas range:[start,end] as V8 bailed on optimization.

Function specific performance tests

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