| var at, // The index of the current character |
| ch, // The current character |
| escapee = { |
| '"': '"', |
| '\\': '\\', |
| '/': '/', |
| b: '\b', |
| f: '\f', |
| n: '\n', |
| r: '\r', |
| t: '\t' |
| }, |
| text, |
| |
| error = function (m) { |
| // Call error when something is wrong. |
| throw { |
| name: 'SyntaxError', |
| message: m, |
| at: at, |
| text: text |
| }; |
| }, |
| |
| next = function (c) { |
| // If a c parameter is provided, verify that it matches the current character. |
| if (c && c !== ch) { |
| error("Expected '" + c + "' instead of '" + ch + "'"); |
| } |
| |
| // Get the next character. When there are no more characters, |
| // return the empty string. |
| |
| ch = text.charAt(at); |
| at += 1; |
| return ch; |
| }, |
| |
| number = function () { |
| // Parse a number value. |
| var number, |
| string = ''; |
| |
| if (ch === '-') { |
| string = '-'; |
| next('-'); |
| } |
| while (ch >= '0' && ch <= '9') { |
| string += ch; |
| next(); |
| } |
| if (ch === '.') { |
| string += '.'; |
| while (next() && ch >= '0' && ch <= '9') { |
| string += ch; |
| } |
| } |
| if (ch === 'e' || ch === 'E') { |
| string += ch; |
| next(); |
| if (ch === '-' || ch === '+') { |
| string += ch; |
| next(); |
| } |
| while (ch >= '0' && ch <= '9') { |
| string += ch; |
| next(); |
| } |
| } |
| number = +string; |
| if (!isFinite(number)) { |
| error("Bad number"); |
| } else { |
| return number; |
| } |
| }, |
| |
| string = function () { |
| // Parse a string value. |
| var hex, |
| i, |
| string = '', |
| uffff; |
| |
| // When parsing for string values, we must look for " and \ characters. |
| if (ch === '"') { |
| while (next()) { |
| if (ch === '"') { |
| next(); |
| return string; |
| } else if (ch === '\\') { |
| next(); |
| if (ch === 'u') { |
| uffff = 0; |
| for (i = 0; i < 4; i += 1) { |
| hex = parseInt(next(), 16); |
| if (!isFinite(hex)) { |
| break; |
| } |
| uffff = uffff * 16 + hex; |
| } |
| string += String.fromCharCode(uffff); |
| } else if (typeof escapee[ch] === 'string') { |
| string += escapee[ch]; |
| } else { |
| break; |
| } |
| } else { |
| string += ch; |
| } |
| } |
| } |
| error("Bad string"); |
| }, |
| |
| white = function () { |
| |
| // Skip whitespace. |
| |
| while (ch && ch <= ' ') { |
| next(); |
| } |
| }, |
| |
| word = function () { |
| |
| // true, false, or null. |
| |
| switch (ch) { |
| case 't': |
| next('t'); |
| next('r'); |
| next('u'); |
| next('e'); |
| return true; |
| case 'f': |
| next('f'); |
| next('a'); |
| next('l'); |
| next('s'); |
| next('e'); |
| return false; |
| case 'n': |
| next('n'); |
| next('u'); |
| next('l'); |
| next('l'); |
| return null; |
| } |
| error("Unexpected '" + ch + "'"); |
| }, |
| |
| value, // Place holder for the value function. |
| |
| array = function () { |
| |
| // Parse an array value. |
| |
| var array = []; |
| |
| if (ch === '[') { |
| next('['); |
| white(); |
| if (ch === ']') { |
| next(']'); |
| return array; // empty array |
| } |
| while (ch) { |
| array.push(value()); |
| white(); |
| if (ch === ']') { |
| next(']'); |
| return array; |
| } |
| next(','); |
| white(); |
| } |
| } |
| error("Bad array"); |
| }, |
| |
| object = function () { |
| |
| // Parse an object value. |
| |
| var key, |
| object = {}; |
| |
| if (ch === '{') { |
| next('{'); |
| white(); |
| if (ch === '}') { |
| next('}'); |
| return object; // empty object |
| } |
| while (ch) { |
| key = string(); |
| white(); |
| next(':'); |
| if (Object.hasOwnProperty.call(object, key)) { |
| error('Duplicate key "' + key + '"'); |
| } |
| object[key] = value(); |
| white(); |
| if (ch === '}') { |
| next('}'); |
| return object; |
| } |
| next(','); |
| white(); |
| } |
| } |
| error("Bad object"); |
| }; |
| |
| value = function () { |
| |
| // Parse a JSON value. It could be an object, an array, a string, a number, |
| // or a word. |
| |
| white(); |
| switch (ch) { |
| case '{': |
| return object(); |
| case '[': |
| return array(); |
| case '"': |
| return string(); |
| case '-': |
| return number(); |
| default: |
| return ch >= '0' && ch <= '9' ? number() : word(); |
| } |
| }; |
| |
| // Return the json_parse function. It will have access to all of the above |
| // functions and variables. |
| |
| module.exports = function (source, reviver) { |
| var result; |
| |
| text = source; |
| at = 0; |
| ch = ' '; |
| result = value(); |
| white(); |
| if (ch) { |
| error("Syntax error"); |
| } |
| |
| // If there is a reviver function, we recursively walk the new structure, |
| // passing each name/value pair to the reviver function for possible |
| // transformation, starting with a temporary root object that holds the result |
| // in an empty key. If there is not a reviver function, we simply return the |
| // result. |
| |
| return typeof reviver === 'function' ? (function walk(holder, key) { |
| var k, v, value = holder[key]; |
| if (value && typeof value === 'object') { |
| for (k in value) { |
| if (Object.prototype.hasOwnProperty.call(value, k)) { |
| v = walk(value, k); |
| if (v !== undefined) { |
| value[k] = v; |
| } else { |
| delete value[k]; |
| } |
| } |
| } |
| } |
| return reviver.call(holder, key, value); |
| }({'': result}, '')) : result; |
| }; |