less.js/lib/less/less-error.js

var utils = require("./utils");

var LessError = module.exports = function LessError(e, importManager, currentFilename) {

    Error.call(this);

    var filename = e.filename || currentFilename;

    if (importManager && filename) {
        var input = importManager.contents[filename],
            loc = utils.getLocation(e.index, input),
            line = loc.line,
            col  = loc.column,
            callLine = e.call && utils.getLocation(e.call, input).line,
            lines = input.split('\n');

        this.type = e.type || 'Syntax';
        this.filename = filename;
        this.index = e.index;
        this.line = typeof line === 'number' ? line + 1 : null;
        this.callLine = callLine + 1;
        this.callExtract = lines[callLine];
        this.column = col;
        this.extract = [
            lines[line - 1],
            lines[line],
            lines[line + 1]
        ];
    }
    this.message = e.message;
    this.stack = e.stack;
};

if (typeof Object.create === 'undefined') {
    var F = function () {};
    F.prototype = Error.prototype;
    LessError.prototype = new F();
} else {
    LessError.prototype = Object.create(Error.prototype);
}

LessError.prototype.constructor = LessError;