text: ﻿/* Parse function for JavaScript. Makes use of the tokenizer from
   * tokenizecsharp.js. Note that your parsers do not have to be
   * this complicated -- if you don't want to recognize local variables,
   * in many languages it is enough to just look for braces, semicolons,
   * parentheses, etc, and know when you are inside a string or comment.
   *
   * See manual.html for more info about the parser interface.
   */
  
  var JSParser = Editor.Parser = (function() {
    // Token types that can be considered to be atoms.
    var atomicTypes = {"atom": true, "number": true, "variable": true, "string": true, "regexp": true};
    // Setting that can be used to have JSON data indent properly.
    var json = false;
    // Constructor for the lexical context objects.
    function CSharpLexical(indented, column, type, align, prev, info) {
      // indentation at start of this line
      this.indented = indented;
      // column at which this scope was opened
      this.column = column;
      // type of scope ('vardef', 'stat' (statement), 'form' (special form), '[', '{', or '(')
      this.type = type;
      // '[', '{', or '(' blocks that have any text after their opening
      // character are said to be 'aligned' -- any lines below are
      // indented all the way to the opening character.
      if (align != null)
        this.align = align;
      // Parent scope, if any.
      this.prev = prev;
      this.info = info;
    }
  
    // CSharp indentation rules.
    function indentCSharp(lexical) {
      return function(firstChars) {
        var firstChar = firstChars && firstChars.charAt(0), type = lexical.type;
        var closing = firstChar == type;
        if (type == "vardef")
          return lexical.indented + 4;
        else if (type == "form" && firstChar == "{")
          return lexical.indented;
        else if (type == "stat" || type == "form")
          return lexical.indented + indentUnit;
        else if (lexical.info == "switch" && !closing)
          return lexical.indented + (/^(?:case|default)\b/.test(firstChars) ? indentUnit : 2 * indentUnit);
        else if (lexical.align)
          return lexical.column - (closing ? 1 : 0);
        else
          return lexical.indented + (closing ? 0 : indentUnit);
      };
    }
  
    // The parser-iterator-producing function itself.
    function parseCSharp(input, basecolumn) {
      // Wrap the input in a token stream
      var tokens = tokenizeCSharp(input);
      // The parser state. cc is a stack of actions that have to be
      // performed to finish the current statement. For example we might
      // know that we still need to find a closing parenthesis and a
      // semicolon. Actions at the end of the stack go first. It is
      // initialized with an infinitely looping action that consumes
      // whole statements.
      var cc = [statements];
      // The lexical scope, used mostly for indentation.
      var lexical = new CSharpLexical((basecolumn || 0) - indentUnit, 0, "block", false);
      // Current column, and the indentation at the start of the current
      // line. Used to create lexical scope objects.
      var column = 0;
      var indented = 0;
      // Variables which are used by the mark, cont, and pass functions
      // below to communicate with the driver loop in the 'next'
      // function.
      var consume, marked;
  
      // The iterator object.
      var parser = {next: next, copy: copy};
  
      function next(){
        // Start by performing any 'lexical' actions (adjusting the
        // lexical variable), or the operations below will be working
        // with the wrong lexical state.
        while(cc[cc.length - 1].lex)
          cc.pop()();
  
        // Fetch a token.
        var token = tokens.next();
  
        // Adjust column and indented.
        if (token.type == "whitespace" && column == 0)
          indented = token.value.length;
        column += token.value.length;
        if (token.content == "\n"){
          indented = column = 0;
          // If the lexical scope's align property is still undefined at
          // the end of the line, it is an un-aligned scope.
          if (!("align" in lexical))
            lexical.align = false;
          // Newline tokens get an indentation function associated with
          // them.
          token.indentation = indentCSharp(lexical);
        }
        // No more processing for meaningless tokens.
        if (token.type == "whitespace" || token.type == "comment")
          return token;
        // When a meaningful token is found and the lexical scope's
        // align is undefined, it is an aligned scope.
        if (!("align" in lexical))
          lexical.align = true;
  
        // Execute actions until one 'consumes' the token and we can
        // return it.
        while(true) {
          consume = marked = false;
          // Take and execute the topmost action.
          cc.pop()(token.type, token.content);
          if (consume){
            // Marked is used to change the style of the current token.
            if (marked)
              token.style = marked;
            return token;
          }
        }
      }
  
      // This makes a copy of the parser state. It stores all the
      // stateful variables in a closure, and returns a function that
      // will restore them when called with a new input stream. Note
      // that the cc array has to be copied, because it is contantly
      // being modified. Lexical objects are not mutated, and context
      // objects are not mutated in a harmful way, so they can be shared
      // between runs of the parser.
      function copy(){
        var _lexical = lexical, _cc = cc.concat([]), _tokenState = tokens.state;
  
        return function copyParser(input){
          lexical = _lexical;
          cc = _cc.concat([]); // copies the array
          column = indented = 0;
          tokens = tokenizeCSharp(input, _tokenState);
          return parser;
        };
      }
  
      // Helper function for pushing a number of actions onto the cc
      // stack in reverse order.
      function push(fs){
        for (var i = fs.length - 1; i >= 0; i--)
          cc.push(fs[i]);
      }
      // cont and pass are used by the action functions to add other
      // actions to the stack. cont will cause the current token to be
      // consumed, pass will leave it for the next action.
      function cont(){
        push(arguments);
        consume = true;
      }
      function pass(){
        push(arguments);
        consume = false;
      }
      // Used to change the style of the current token.
      function mark(style){
        marked = style;
      }
  
      // Push a new lexical context of the given type.
      function pushlex(type, info) {
        var result = function(){
          lexical = new CSharpLexical(indented, column, type, null, lexical, info)
        };
        result.lex = true;
        return result;
      }
      // Pop off the current lexical context.
      function poplex(){
        lexical = lexical.prev;
      }
      poplex.lex = true;
      // The 'lex' flag on these actions is used by the 'next' function
      // to know they can (and have to) be ran before moving on to the
      // next token.
  
      // Creates an action that discards tokens until it finds one of
      // the given type.
      function expect(wanted){
        return function expecting(type){
          if (type == wanted) cont();
          else cont(arguments.callee);
        };
      }
  
      // Looks for a statement, and then calls itself.
      function statements(type){
        return pass(statement, statements);
      }
      // Dispatches various types of statements based on the type of the
      // current token.
      function statement(type){
        if (type == "var") cont(pushlex("vardef"), vardef1, expect(";"), poplex);
        else if (type == "keyword a") cont(pushlex("form"), expression, statement, poplex);
        else if (type == "keyword b") cont(pushlex("form"), statement, poplex);
        else if (type == "{" && json) cont(pushlex("}"), commasep(objprop, "}"), poplex);
        else if (type == "{") cont(pushlex("}"), block, poplex);
        else if (type == "function") cont(functiondef);
        else if (type == "for") cont(pushlex("form"), expect("("), pushlex(")"), forspec1, expect(")"), poplex, statement, poplex);
        else if (type == "variable") cont(pushlex("stat"), maybelabel);
        else if (type == "switch") cont(pushlex("form"), expression, pushlex("}", "switch"), expect("{"), block, poplex, poplex);
        else if (type == "case") cont(expression, expect(":"));
        else if (type == "default") cont(expect(":"));
        else if (type == "catch") cont(pushlex("form"), expect("("), funarg, expect(")"), statement, poplex);
  
        else if (type == "class") cont(classdef);
        else if (type == "keyword d") cont(statement);
  
        else pass(pushlex("stat"), expression, expect(";"), poplex);
      }
      // Dispatch expression types.
      function expression(type){
        if (atomicTypes.hasOwnProperty(type)) cont(maybeoperator);
        else if (type == "function") cont(functiondef);
        else if (type == "keyword c") cont(expression);
        else if (type == "(") cont(pushlex(")"), expression, expect(")"), poplex, maybeoperator);
        else if (type == "operator") cont(expression);
        else if (type == "[") cont(pushlex("]"), commasep(expression, "]"), poplex, maybeoperator);
        else if (type == "{") cont(pushlex("}"), commasep(objprop, "}"), poplex, maybeoperator);
      }
      // Called for places where operators, function calls, or
      // subscripts are valid. Will skip on to the next action if none
      // is found.
      function maybeoperator(type){
        if (type == "operator") cont(expression);
        else if (type == "(") cont(pushlex(")"), expression, commasep(expression, ")"), poplex, maybeoperator);
        else if (type == ".") cont(property, maybeoperator);
        else if (type == "[") cont(pushlex("]"), expression, expect("]"), poplex, maybeoperator);
      }
      // When a statement starts with a variable name, it might be a
      // label. If no colon follows, it's a regular statement.
      function maybelabel(type){
        if (type == ":") cont(poplex, statement);
        else if (type == "(") cont(commasep(funarg, ")"), poplex, statement); // method definition
        else if (type == "{") cont(poplex, pushlex("}"), block, poplex); // property definition
        else pass(maybeoperator, expect(";"), poplex);
      }
      // Property names need to have their style adjusted -- the
      // tokenizer thinks they are variables.
      function property(type){
        if (type == "variable") {mark("csharp-property"); cont();}
      }
      // This parses a property and its value in an object literal.
      function objprop(type){
        if (type == "variable") mark("csharp-property");
        if (atomicTypes.hasOwnProperty(type)) cont(expect(":"), expression);
      }
      // Parses a comma-separated list of the things that are recognized
      // by the 'what' argument.
      function commasep(what, end){
        function proceed(type) {
          if (type == ",") cont(what, proceed);
          else if (type == end) cont();
          else cont(expect(end));
        };
        return function commaSeparated(type) {
          if (type == end) cont();
          else pass(what, proceed);
        };
      }
      // Look for statements until a closing brace is found.
      function block(type){
        if (type == "}") cont();
        else pass(statement, block);
      }
      // Variable definitions are split into two actions -- 1 looks for
      // a name or the end of the definition, 2 looks for an '=' sign or
      // a comma.
      function vardef1(type, value){
        if (type == "variable"){cont(vardef2);}
        else cont();
      }
      function vardef2(type, value){
        if (value == "=") cont(expression, vardef2);
        else if (type == ",") cont(vardef1);
      }
      // For loops.
      function forspec1(type){
        if (type == "var") cont(vardef1, forspec2);
        else if (type == "keyword d") cont(vardef1, forspec2);
        else if (type == ";") pass(forspec2);
        else if (type == "variable") cont(formaybein);
        else pass(forspec2);
      }
      function formaybein(type, value){
        if (value == "in") cont(expression);
        else cont(maybeoperator, forspec2);
      }
      function forspec2(type, value){
        if (type == ";") cont(forspec3);
        else if (value == "in") cont(expression);
        else cont(expression, expect(";"), forspec3);
      }
      function forspec3(type) {
        if (type == ")") pass();
        else cont(expression);
      }
      // A function definition creates a new context, and the variables
      // in its argument list have to be added to this context.
      function functiondef(type, value){
        if (type == "variable") cont(functiondef);
        else if (type == "(") cont(commasep(funarg, ")"), statement);
      }
      function funarg(type, value){
        if (type == "variable"){cont();}
      }
  
      function classdef(type) {
          if (type == "variable") cont(classdef, statement);
          else if (type == ":") cont(classdef, statement);
      }
  
      return parser;
    }
  
    return {
      make: parseCSharp,
      electricChars: "{}:",
      configure: function(obj) {
        if (obj.json != null) json = obj.json;
      }
    };
  })();
  