define(['exports', 'module', '../exception'], function (exports, module, _exception) {
  'use strict';

  // istanbul ignore next

  function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

  var _Exception = _interopRequireDefault(_exception);

  function Visitor() {
    this.parents = [];
  }

  Visitor.prototype = {
    constructor: Visitor,
    mutating: false,

    // Visits a given value. If mutating, will replace the value if necessary.
    acceptKey: function acceptKey(node, name) {
      var value = this.accept(node[name]);
      if (this.mutating) {
        // Hacky sanity check: This may have a few false positives for type for the helper
        // methods but will generally do the right thing without a lot of overhead.
        if (value && !Visitor.prototype[value.type]) {
          throw new _Exception['default']('Unexpected node type "' + value.type + '" found when accepting ' + name + ' on ' + node.type);
        }
        node[name] = value;
      }
    },

    // Performs an accept operation with added sanity check to ensure
    // required keys are not removed.
    acceptRequired: function acceptRequired(node, name) {
      this.acceptKey(node, name);

      if (!node[name]) {
        throw new _Exception['default'](node.type + ' requires ' + name);
      }
    },

    // Traverses a given array. If mutating, empty respnses will be removed
    // for child elements.
    acceptArray: function acceptArray(array) {
      for (var i = 0, l = array.length; i < l; i++) {
        this.acceptKey(array, i);

        if (!array[i]) {
          array.splice(i, 1);
          i--;
          l--;
        }
      }
    },

    accept: function accept(object) {
      if (!object) {
        return;
      }

      /* istanbul ignore next: Sanity code */
      if (!this[object.type]) {
        throw new _Exception['default']('Unknown type: ' + object.type, object);
      }

      if (this.current) {
        this.parents.unshift(this.current);
      }
      this.current = object;

      var ret = this[object.type](object);

      this.current = this.parents.shift();

      if (!this.mutating || ret) {
        return ret;
      } else if (ret !== false) {
        return object;
      }
    },

    Program: function Program(program) {
      this.acceptArray(program.body);
    },

    MustacheStatement: visitSubExpression,
    Decorator: visitSubExpression,

    BlockStatement: visitBlock,
    DecoratorBlock: visitBlock,

    PartialStatement: visitPartial,
    PartialBlockStatement: function PartialBlockStatement(partial) {
      visitPartial.call(this, partial);

      this.acceptKey(partial, 'program');
    },

    ContentStatement: function ContentStatement() /* content */{},
    CommentStatement: function CommentStatement() /* comment */{},

    SubExpression: visitSubExpression,

    PathExpression: function PathExpression() /* path */{},

    StringLiteral: function StringLiteral() /* string */{},
    NumberLiteral: function NumberLiteral() /* number */{},
    BooleanLiteral: function BooleanLiteral() /* bool */{},
    UndefinedLiteral: function UndefinedLiteral() /* literal */{},
    NullLiteral: function NullLiteral() /* literal */{},

    Hash: function Hash(hash) {
      this.acceptArray(hash.pairs);
    },
    HashPair: function HashPair(pair) {
      this.acceptRequired(pair, 'value');
    }
  };

  function visitSubExpression(mustache) {
    this.acceptRequired(mustache, 'path');
    this.acceptArray(mustache.params);
    this.acceptKey(mustache, 'hash');
  }
  function visitBlock(block) {
    visitSubExpression.call(this, block);

    this.acceptKey(block, 'program');
    this.acceptKey(block, 'inverse');
  }
  function visitPartial(partial) {
    this.acceptRequired(partial, 'name');
    this.acceptArray(partial.params);
    this.acceptKey(partial, 'hash');
  }

  module.exports = Visitor;
});
//# sourceMappingURL=data:application/json;charset=utf-8;base64,{"version":3,"sources":["../../../../lib/handlebars/compiler/visitor.js"],"names":[],"mappings":";;;;;;;;;AAEA,WAAS,OAAO,GAAG;AACjB,QAAI,CAAC,OAAO,GAAG,EAAE,CAAC;GACnB;;AAED,SAAO,CAAC,SAAS,GAAG;AAClB,eAAW,EAAE,OAAO;AACpB,YAAQ,EAAE,KAAK;;;AAGf,aAAS,EAAE,mBAAS,IAAI,EAAE,IAAI,EAAE;AAC9B,UAAI,KAAK,GAAG,IAAI,CAAC,MAAM,CAAC,IAAI,CAAC,IAAI,CAAC,CAAC,CAAC;AACpC,UAAI,IAAI,CAAC,QAAQ,EAAE;;;AAGjB,YAAI,KAAK,IAAI,CAAC,OAAO,CAAC,SAAS,CAAC,KAAK,CAAC,IAAI,CAAC,EAAE;AAC3C,gBAAM,0BAAc,wBAAwB,GAAG,KAAK,CAAC,IAAI,GAAG,yBAAyB,GAAG,IAAI,GAAG,MAAM,GAAG,IAAI,CAAC,IAAI,CAAC,CAAC;SACpH;AACD,YAAI,CAAC,IAAI,CAAC,GAAG,KAAK,CAAC;OACpB;KACF;;;;AAID,kBAAc,EAAE,wBAAS,IAAI,EAAE,IAAI,EAAE;AACnC,UAAI,CAAC,SAAS,CAAC,IAAI,EAAE,IAAI,CAAC,CAAC;;AAE3B,UAAI,CAAC,IAAI,CAAC,IAAI,CAAC,EAAE;AACf,cAAM,0BAAc,IAAI,CAAC,IAAI,GAAG,YAAY,GAAG,IAAI,CAAC,CAAC;OACtD;KACF;;;;AAID,eAAW,EAAE,qBAAS,KAAK,EAAE;AAC3B,WAAK,IAAI,CAAC,GAAG,CAAC,EAAE,CAAC,GAAG,KAAK,CAAC,MAAM,EAAE,CAAC,GAAG,CAAC,EAAE,CAAC,EAAE,EAAE;AAC5C,YAAI,CAAC,SAAS,CAAC,KAAK,EAAE,CAAC,CAAC,CAAC;;AAEzB,YAAI,CAAC,KAAK,CAAC,CAAC,CAAC,EAAE;AACb,eAAK,CAAC,MAAM,CAAC,CAAC,EAAE,CAAC,CAAC,CAAC;AACnB,WAAC,EAAE,CAAC;AACJ,WAAC,EAAE,CAAC;SACL;OACF;KACF;;AAED,UAAM,EAAE,gBAAS,MAAM,EAAE;AACvB,UAAI,CAAC,MAAM,EAAE;AACX,eAAO;OACR;;;AAGD,UAAI,CAAC,IAAI,CAAC,MAAM,CAAC,IAAI,CAAC,EAAE;AACtB,cAAM,0BAAc,gBAAgB,GAAG,MAAM,CAAC,IAAI,EAAE,MAAM,CAAC,CAAC;OAC7D;;AAED,UAAI,IAAI,CAAC,OAAO,EAAE;AAChB,YAAI,CAAC,OAAO,CAAC,OAAO,CAAC,IAAI,CAAC,OAAO,CAAC,CAAC;OACpC;AACD,UAAI,CAAC,OAAO,GAAG,MAAM,CAAC;;AAEtB,UAAI,GAAG,GAAG,IAAI,CAAC,MAAM,CAAC,IAAI,CAAC,CAAC,MAAM,CAAC,CAAC;;AAEpC,UAAI,CAAC,OAAO,GAAG,IAAI,CAAC,OAAO,CAAC,KAAK,EAAE,CAAC;;AAEpC,UAAI,CAAC,IAAI,CAAC,QAAQ,IAAI,GAAG,EAAE;AACzB,eAAO,GAAG,CAAC;OACZ,MAAM,IAAI,GAAG,KAAK,KAAK,EAAE;AACxB,eAAO,MAAM,CAAC;OACf;KACF;;AAED,WAAO,EAAE,iBAAS,OAAO,EAAE;AACzB,UAAI,CAAC,WAAW,CAAC,OAAO,CAAC,IAAI,CAAC,CAAC;KAChC;;AAED,qBAAiB,EAAE,kBAAkB;AACrC,aAAS,EAAE,kBAAkB;;AAE7B,kBAAc,EAAE,UAAU;AAC1B,kBAAc,EAAE,UAAU;;AAE1B,oBAAgB,EAAE,YAAY;AAC9B,yBAAqB,EAAE,+BAAS,OAAO,EAAE;AACvC,kBAAY,CAAC,IAAI,CAAC,IAAI,EAAE,OAAO,CAAC,CAAC;;AAEjC,UAAI,CAAC,SAAS,CAAC,OAAO,EAAE,SAAS,CAAC,CAAC;KACpC;;AAED,oBAAgB,EAAE,yCAAwB,EAAE;AAC5C,oBAAgB,EAAE,yCAAwB,EAAE;;AAE5C,iBAAa,EAAE,kBAAkB;;AAEjC,kBAAc,EAAE,oCAAqB,EAAE;;AAEvC,iBAAa,EAAE,qCAAuB,EAAE;AACxC,iBAAa,EAAE,qCAAuB,EAAE;AACxC,kBAAc,EAAE,oCAAqB,EAAE;AACvC,oBAAgB,EAAE,yCAAwB,EAAE;AAC5C,eAAW,EAAE,oCAAwB,EAAE;;AAEvC,QAAI,EAAE,cAAS,IAAI,EAAE;AACnB,UAAI,CAAC,WAAW,CAAC,IAAI,CAAC,KAAK,CAAC,CAAC;KAC9B;AACD,YAAQ,EAAE,kBAAS,IAAI,EAAE;AACvB,UAAI,CAAC,cAAc,CAAC,IAAI,EAAE,OAAO,CAAC,CAAC;KACpC;GACF,CAAC;;AAEF,WAAS,kBAAkB,CAAC,QAAQ,EAAE;AACpC,QAAI,CAAC,cAAc,CAAC,QAAQ,EAAE,MAAM,CAAC,CAAC;AACtC,QAAI,CAAC,WAAW,CAAC,QAAQ,CAAC,MAAM,CAAC,CAAC;AAClC,QAAI,CAAC,SAAS,CAAC,QAAQ,EAAE,MAAM,CAAC,CAAC;GAClC;AACD,WAAS,UAAU,CAAC,KAAK,EAAE;AACzB,sBAAkB,CAAC,IAAI,CAAC,IAAI,EAAE,KAAK,CAAC,CAAC;;AAErC,QAAI,CAAC,SAAS,CAAC,KAAK,EAAE,SAAS,CAAC,CAAC;AACjC,QAAI,CAAC,SAAS,CAAC,KAAK,EAAE,SAAS,CAAC,CAAC;GAClC;AACD,WAAS,YAAY,CAAC,OAAO,EAAE;AAC7B,QAAI,CAAC,cAAc,CAAC,OAAO,EAAE,MAAM,CAAC,CAAC;AACrC,QAAI,CAAC,WAAW,CAAC,OAAO,CAAC,MAAM,CAAC,CAAC;AACjC,QAAI,CAAC,SAAS,CAAC,OAAO,EAAE,MAAM,CAAC,CAAC;GACjC;;mBAEc,OAAO","file":"visitor.js","sourcesContent":["import Exception from '../exception';\n\nfunction Visitor() {\n  this.parents = [];\n}\n\nVisitor.prototype = {\n  constructor: Visitor,\n  mutating: false,\n\n  // Visits a given value. If mutating, will replace the value if necessary.\n  acceptKey: function(node, name) {\n    let value = this.accept(node[name]);\n    if (this.mutating) {\n      // Hacky sanity check: This may have a few false positives for type for the helper\n      // methods but will generally do the right thing without a lot of overhead.\n      if (value && !Visitor.prototype[value.type]) {\n        throw new Exception('Unexpected node type \"' + value.type + '\" found when accepting ' + name + ' on ' + node.type);\n      }\n      node[name] = value;\n    }\n  },\n\n  // Performs an accept operation with added sanity check to ensure\n  // required keys are not removed.\n  acceptRequired: function(node, name) {\n    this.acceptKey(node, name);\n\n    if (!node[name]) {\n      throw new Exception(node.type + ' requires ' + name);\n    }\n  },\n\n  // Traverses a given array. If mutating, empty respnses will be removed\n  // for child elements.\n  acceptArray: function(array) {\n    for (let i = 0, l = array.length; i < l; i++) {\n      this.acceptKey(array, i);\n\n      if (!array[i]) {\n        array.splice(i, 1);\n        i--;\n        l--;\n      }\n    }\n  },\n\n  accept: function(object) {\n    if (!object) {\n      return;\n    }\n\n    /* istanbul ignore next: Sanity code */\n    if (!this[object.type]) {\n      throw new Exception('Unknown type: ' + object.type, object);\n    }\n\n    if (this.current) {\n      this.parents.unshift(this.current);\n    }\n    this.current = object;\n\n    let ret = this[object.type](object);\n\n    this.current = this.parents.shift();\n\n    if (!this.mutating || ret) {\n      return ret;\n    } else if (ret !== false) {\n      return object;\n    }\n  },\n\n  Program: function(program) {\n    this.acceptArray(program.body);\n  },\n\n  MustacheStatement: visitSubExpression,\n  Decorator: visitSubExpression,\n\n  BlockStatement: visitBlock,\n  DecoratorBlock: visitBlock,\n\n  PartialStatement: visitPartial,\n  PartialBlockStatement: function(partial) {\n    visitPartial.call(this, partial);\n\n    this.acceptKey(partial, 'program');\n  },\n\n  ContentStatement: function(/* content */) {},\n  CommentStatement: function(/* comment */) {},\n\n  SubExpression: visitSubExpression,\n\n  PathExpression: function(/* path */) {},\n\n  StringLiteral: function(/* string */) {},\n  NumberLiteral: function(/* number */) {},\n  BooleanLiteral: function(/* bool */) {},\n  UndefinedLiteral: function(/* literal */) {},\n  NullLiteral: function(/* literal */) {},\n\n  Hash: function(hash) {\n    this.acceptArray(hash.pairs);\n  },\n  HashPair: function(pair) {\n    this.acceptRequired(pair, 'value');\n  }\n};\n\nfunction visitSubExpression(mustache) {\n  this.acceptRequired(mustache, 'path');\n  this.acceptArray(mustache.params);\n  this.acceptKey(mustache, 'hash');\n}\nfunction visitBlock(block) {\n  visitSubExpression.call(this, block);\n\n  this.acceptKey(block, 'program');\n  this.acceptKey(block, 'inverse');\n}\nfunction visitPartial(partial) {\n  this.acceptRequired(partial, 'name');\n  this.acceptArray(partial.params);\n  this.acceptKey(partial, 'hash');\n}\n\nexport default Visitor;\n"]}