TinyJS.cpp

/*
 * TinyJS
 *
 * A single-file Javascript-alike engine
 *
 * Authored By Gordon Williams <gw@pur3.co.uk>
 *
 * Copyright (C) 2009 Pur3 Ltd
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:

 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

 /* Version 0.1  :  (gw) First published on Google Code
    Version 0.11 :  Making sure the 'root' variable never changes
                    'symbol_base' added for the current base of the sybmbol table
    Version 0.12 :  Added findChildOrCreate, changed string passing to use references
                    Fixed broken string encoding in getJSString()
                    Removed getInitCode and added getJSON instead
                    Added nil
                    Added rough JSON parsing
                    Improved example app
    Version 0.13 :  Added tokenEnd/tokenLastEnd to lexer to avoid parsing whitespace
                    Ability to define functions without names
                    Can now do "var mine = function(a,b) { ... };"
                    Slightly better 'trace' function
                    Added findChildOrCreateByPath function
                    Added simple test suite
                    Added skipping of blocks when not executing
    Version 0.14 :  Added parsing of more number types
                    Added parsing of string defined with '
                    Changed nil to null as per spec, added 'undefined'
                    Now set variables with the correct scope, and treat unknown
                               as 'undefined' rather than failing
                    Added proper (I hope) handling of null and undefined
                    Added === check
    Version 0.15 :  Fix for possible memory leaks
    Version 0.16 :  Removal of un-needed findRecursive calls
                    symbol_base removed and replaced with 'scopes' stack
                    Added reference counting a proper tree structure
                        (Allowing pass by reference)
                    Allowed JSON output to output IDs, not strings
                    Added get/set for array indices
                    Changed Callbacks to include user data pointer
                    Added some support for objects
                    Added more Java-esque builtin functions
    Version 0.17 :  Now we don't deepCopy the parent object of the class
                    Added JSON.stringify and eval()
                    Nicer JSON indenting
                    Fixed function output in JSON
                    Added evaluateComplex
                    Fixed some reentrancy issues with evaluate/execute
    Version 0.18 :  Fixed some issues with code being executed when it shouldn't
    Version 0.19 :  Added array.length
                    Changed '__parent' to 'prototype' to bring it more in line with javascript
    Version 0.20 :  Added '%' operator
    Version 0.21 :  Added array type
                    String.length() no more - now String.length
                    Added extra constructors to reduce confusion
                    Fixed checks against undefined
    Version 0.22 :  First part of ardi's changes:
                        sprintf -> sprintf_s
                        extra tokens parsed
                        array memory leak fixed
                    Fixed memory leak in evaluateComplex
                    Fixed memory leak in FOR loops
                    Fixed memory leak for unary minus
    Version 0.23 :  Allowed evaluate[Complex] to take in semi-colon separated
                      statements and then only return the value from the last one.
                      Also checks to make sure *everything* was parsed.
                    Ints + doubles are now stored in binary form (faster + more precise)
    Version 0.24 :  More useful error for maths ops
                    Don't dump everything on a match error.
    Version 0.25 :  Better string escaping
    Version 0.26 :  Add CScriptVar::equals
                    Add built-in array functions
    Version 0.27 :  Added OZLB's TinyJS.setVariable (with some tweaks)
                    Added OZLB's Maths Functions
    Version 0.28 :  Ternary operator
                    Rudimentary call stack on error
                    Added String Character functions
                    Added shift operators
    Version 0.29 :  Added new object via functions
                    Fixed getString() for double on some platforms
    Version 0.30 :  Rlyeh Mario's patch for Math Functions on VC++
    Version 0.31 :  Add exec() to TinyJS functions
                    Now print quoted JSON that can be read by PHP/Python parsers
                    Fixed postfix increment operator
    Version 0.32 :  Fixed Math.randInt on 32 bit PCs, where it was broken
    Version 0.33 :  Fixed Memory leak + brokenness on === comparison

     NOTE:
           Constructing an array with an initial length 'Array(5)' doesn't work
           Recursive loops of data such as a.foo = a; fail to be garbage collected
           length variable cannot be set
           The postfix increment operator returns the current value, not the previous as it should.
           There is no prefix increment operator
     TODO:
           Utility va-args style function in TinyJS for executing a function directly
           Merge the parsing of expressions/statements so eval("statement") works like we'd expect.
           Move 'shift' implementation into mathsOp

  */

#include "TinyJS.h"
#include "TinyJS_SyntaxTree.h"
#include <assert.h>

#define ASSERT(X) assert(X)
  /* Frees the given link IF it isn't owned by anything else */
#define CLEAN(x) { CScriptVarLink *__v = x; if (__v && !__v->owned) { delete __v; } }
/* Create a LINK to point to VAR and free the old link.
 * BUT this is more clever - it tries to keep the old link if it's not owned to save allocations */
#define CREATE_LINK(LINK, VAR) { if (!LINK || LINK->owned) LINK = new CScriptVarLink(VAR); else LINK->replaceWith(VAR); }

#include <string>
#include <string.h>
#include <sstream>
#include <cstdlib>
#include <stdio.h>
#include <fstream>

// support both windows and linux
#ifdef _MSC_VER
#include <windows.h>

#define GETLIB(a,b) LoadLibrary(a)
#define GETSYMBOL(a,b) GetProcAddress(a, b)
#define LIBNAME ".\\jit.dll"
#define GETBUILDERROR "Load failed with 0x%x\n", GetLastError() 
#define FREELIB(a) FreeLibrary(a)
#define RTLD_NOW 0
#else
#include <dlfcn.h>   

#define GETLIB(a,b) dlopen(a, b)
#define GETSYMBOL(a,b) dlsym(a, b)
#define LIBNAME "./jit.so"
#define GETBUILDERROR "%s\n", dlerror()
#define FREELIB(a) dlclose(a)
#endif

using namespace std;

#ifdef _WIN32
#ifdef _DEBUG
#ifndef DBG_NEW
#define DBG_NEW new ( _NORMAL_BLOCK , __FILE__ , __LINE__ )
#define new DBG_NEW
#endif
#endif
#endif

#ifdef __GNUC__
#define vsprintf_s vsnprintf
#define sprintf_s snprintf
#define _strdup strdup
#endif

// ----------------------------------------------------------------------------------- Memory Debug

#define DEBUG_MEMORY 0

#if DEBUG_MEMORY

vector<CScriptVar*> allocatedVars;
vector<CScriptVarLink*> allocatedLinks;

void mark_allocated(CScriptVar *v)
{
    allocatedVars.push_back(v);
}

void mark_deallocated(CScriptVar *v)
{
    for(size_t i = 0; i < allocatedVars.size(); i++)
    {
        if(allocatedVars[i] == v)
        {
            allocatedVars.erase(allocatedVars.begin() + i);
            break;
        }
    }
}

void mark_allocated(CScriptVarLink *v)
{
    allocatedLinks.push_back(v);
}

void mark_deallocated(CScriptVarLink *v)
{
    for(size_t i = 0; i < allocatedLinks.size(); i++)
    {
        if(allocatedLinks[i] == v)
        {
            allocatedLinks.erase(allocatedLinks.begin() + i);
            break;
        }
    }
}

void show_allocated()
{
    for(size_t i = 0; i < allocatedVars.size(); i++)
    {
        printf("ALLOCATED, %d refs\n", allocatedVars[i]->getRefs());
        allocatedVars[i]->trace("  ");
    }
    for(size_t i = 0; i < allocatedLinks.size(); i++)
    {
        printf("ALLOCATED LINK %s, allocated[%d] to \n", allocatedLinks[i]->name.c_str(), allocatedLinks[i]->var->getRefs());
        allocatedLinks[i]->var->trace("  ");
    }
    allocatedVars.clear();
    allocatedLinks.clear();
}
#endif

// ----------------------------------------------------------------------------------- Utils
bool isWhitespace(char ch)
{
    return (ch == ' ') || (ch == '\t') || (ch == '\n') || (ch == '\r');
}

bool isNumeric(char ch)
{
    return (ch >= '0') && (ch <= '9');
}
bool isNumber(const string &str)
{
    for(size_t i = 0; i < str.size(); i++)
        if(!isNumeric(str[i])) return false;
    return true;
}
bool isHexadecimal(char ch)
{
    return ((ch >= '0') && (ch <= '9')) ||
        ((ch >= 'a') && (ch <= 'f')) ||
        ((ch >= 'A') && (ch <= 'F'));
}
bool isAlpha(char ch)
{
    return ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z')) || ch == '_';
}

bool isIDString(const char *s)
{
    if(!isAlpha(*s))
        return false;
    while(*s)
    {
        if(!(isAlpha(*s) || isNumeric(*s)))
            return false;
        s++;
    }
    return true;
}

void replace(string &str, char textFrom, const char *textTo)
{
    int sLen = strlen(textTo);
    size_t p = str.find(textFrom);
    while(p != string::npos)
    {
        str = str.substr(0, p) + textTo + str.substr(p + 1);
        p = str.find(textFrom, p + sLen);
    }
}

/// convert the given string into a quoted string suitable for javascript
std::string getJSString(const std::string &str)
{
    std::string nStr = str;
    for(size_t i = 0; i < nStr.size(); i++)
    {
        const char *replaceWith = "";
        bool replace = true;

        switch(nStr[i])
        {
        case '\\': replaceWith = "\\\\"; break;
        case '\n': replaceWith = "\\n"; break;
        case '\r': replaceWith = "\\r"; break;
        case '\a': replaceWith = "\\a"; break;
        case '"': replaceWith = "\\\""; break;
        default:
        {
            int nCh = ((int)nStr[i]) & 0xFF;
            if(nCh < 32 || nCh>127)
            {
                char buffer[5];
                sprintf_s(buffer, 5, "\\x%02X", nCh);
                replaceWith = buffer;
            }
            else replace = false;
        }
        }

        if(replace)
        {
            nStr = nStr.substr(0, i) + replaceWith + nStr.substr(i + 1);
            i += strlen(replaceWith) - 1;
        }
    }
    return "\"" + nStr + "\"";
}

/** Is the string alphanumeric */
bool isAlphaNum(const std::string &str)
{
    if(str.size() == 0) return true;
    if(!isAlpha(str[0])) return false;
    for(size_t i = 0; i < str.size(); i++)
        if(!(isAlpha(str[i]) || isNumeric(str[i])))
            return false;
    return true;
}

// ----------------------------------------------------------------------------------- CSCRIPTEXCEPTION

CScriptException::CScriptException(const string &exceptionText)
{
    text = exceptionText;
}

// ----------------------------------------------------------------------------------- CSCRIPTLEX

CScriptLex::CScriptLex(const string &input)
{
    data = _strdup(input.c_str());
    dataOwned = true;
    dataStart = 0;
    dataEnd = strlen(data);
    reset();
}

CScriptLex::CScriptLex(CScriptLex *owner, int startChar, int endChar)
{
    data = owner->data;
    dataOwned = false;
    dataStart = startChar;
    dataEnd = endChar;
    reset();
}

CScriptLex::~CScriptLex(void)
{
    if(dataOwned)
        free((void*)data);
}

void CScriptLex::reset()
{
    dataPos = dataStart;
    tokenStart = 0;
    tokenEnd = 0;
    tokenLastEnd = 0;
    tk = 0;
    tkStr = "";
    getNextCh();
    getNextCh();
    getNextToken();
}

void CScriptLex::match(int expected_tk)
{
    if(tk != expected_tk)
    {
        ostringstream errorString;
        errorString << "Got " << getTokenStr(tk) << " expected " << getTokenStr(expected_tk)
            << " at " << getPosition(tokenStart);
        throw new CScriptException(errorString.str());
    }
    getNextToken();
}

string CScriptLex::getTokenStr(int token, bool raw_tokens)
{
    if(token > 32 && token < 128)
    {
        char buf[4] = "' '";
        if(raw_tokens)
        {
            buf[0] = (char)token;
            buf[1] = '\0';
        }
        else
            buf[1] = (char)token;
        return buf;
    }
    switch(token)
    {
    case LEX_EOF: return "EOF";
    case LEX_ID: return "ID";
    case LEX_INT: return "INT";
    case LEX_FLOAT: return "FLOAT";
    case LEX_STR: return "STRING";
    case LEX_EQUAL: return "==";
    case LEX_TYPEEQUAL: return "===";
    case LEX_NEQUAL: return "!=";
    case LEX_NTYPEEQUAL: return "!==";
    case LEX_LEQUAL: return "<=";
    case LEX_LSHIFT: return "<<";
    case LEX_LSHIFTEQUAL: return "<<=";
    case LEX_GEQUAL: return ">=";
    case LEX_RSHIFT: return ">>";
    case LEX_RSHIFTUNSIGNED: return ">>";
    case LEX_RSHIFTEQUAL: return ">>=";
    case LEX_PLUSEQUAL: return "+=";
    case LEX_MINUSEQUAL: return "-=";
    case LEX_PLUSPLUS: return "++";
    case LEX_MINUSMINUS: return "--";
    case LEX_ANDEQUAL: return "&=";
    case LEX_ANDAND: return "&&";
    case LEX_OREQUAL: return "|=";
    case LEX_OROR: return "||";
    case LEX_XOREQUAL: return "^=";
        // reserved words
    case LEX_R_IF: return "if";
    case LEX_R_ELSE: return "else";
    case LEX_R_DO: return "do";
    case LEX_R_WHILE: return "while";
    case LEX_R_FOR: return "for";
    case LEX_R_BREAK: return "break";
    case LEX_R_CONTINUE: return "continue";
    case LEX_R_FUNCTION: return "function";
    case LEX_R_RETURN: return "return";
    case LEX_R_VAR: return "var";
    case LEX_R_TRUE: return "true";
    case LEX_R_FALSE: return "false";
    case LEX_R_NULL: return "null";
    case LEX_R_UNDEFINED: return "undefined";
    case LEX_R_NEW: return "new";
    case LEX_R_RESERVED: return "(internally reserved token)";
    }

    ostringstream msg;
    msg << "?[" << token << "]";
    return msg.str();
}

void CScriptLex::getNextCh()
{
    currCh = nextCh;
    if(dataPos < dataEnd)
        nextCh = data[dataPos];
    else
        nextCh = 0;
    dataPos++;
}

void CScriptLex::getNextToken()
{
    tk = LEX_EOF;
    tkStr.clear();
    while(currCh && isWhitespace(currCh)) getNextCh();
    // newline comments
    if(currCh == '/' && nextCh == '/')
    {
        while(currCh && currCh != '\n') getNextCh();
        getNextCh();
        getNextToken();
        return;
    }
    // block comments
    if(currCh == '/' && nextCh == '*')
    {
        while(currCh && (currCh != '*' || nextCh != '/')) getNextCh();
        getNextCh();
        getNextCh();
        getNextToken();
        return;
    }
    // record beginning of this token
    tokenStart = dataPos - 2;
    // tokens
    if(isAlpha(currCh))
    { //  IDs
        while(isAlpha(currCh) || isNumeric(currCh))
        {
            tkStr += currCh;
            getNextCh();
        }
        tk = LEX_ID;
        if(tkStr == "if") tk = LEX_R_IF;
        else if(tkStr == "else") tk = LEX_R_ELSE;
        else if(tkStr == "do") tk = LEX_R_DO;
        else if(tkStr == "while") tk = LEX_R_WHILE;
        else if(tkStr == "for") tk = LEX_R_FOR;
        else if(tkStr == "break") tk = LEX_R_BREAK;
        else if(tkStr == "continue") tk = LEX_R_CONTINUE;
        else if(tkStr == "function") tk = LEX_R_FUNCTION;
        else if(tkStr == "return") tk = LEX_R_RETURN;
        else if(tkStr == "var") tk = LEX_R_VAR;
        else if(tkStr == "true") tk = LEX_R_TRUE;
        else if(tkStr == "false") tk = LEX_R_FALSE;
        else if(tkStr == "null") tk = LEX_R_NULL;
        else if(tkStr == "undefined") tk = LEX_R_UNDEFINED;
        else if(tkStr == "new") tk = LEX_R_NEW;
        else if(tkStr == TINYJS_OBJECT_FUNCTION_NAME ||
            tkStr == TINYJS_NEW_FUNCTION_NAME ||
            tkStr == TINYJS_ARRAY_FUNCTION_NAME) tk = LEX_R_RESERVED;
    }
    else if(isNumeric(currCh))
    { // Numbers
        bool isHex = false;
        if(currCh == '0') { tkStr += currCh; getNextCh(); }
        if(currCh == 'x')
        {
            isHex = true;
            tkStr += currCh; getNextCh();
        }
        tk = LEX_INT;
        while(isNumeric(currCh) || (isHex && isHexadecimal(currCh)))
        {
            tkStr += currCh;
            getNextCh();
        }
        if(!isHex && currCh == '.')
        {
            tk = LEX_FLOAT;
            tkStr += '.';
            getNextCh();
            while(isNumeric(currCh))
            {
                tkStr += currCh;
                getNextCh();
            }
        }
        // do fancy e-style floating point
        if(!isHex && (currCh == 'e' || currCh == 'E'))
        {
            tk = LEX_FLOAT;
            tkStr += currCh; getNextCh();
            if(currCh == '-') { tkStr += currCh; getNextCh(); }
            while(isNumeric(currCh))
            {
                tkStr += currCh; getNextCh();
            }
        }
    }
    else if(currCh == '"')
    {
        // strings...
        getNextCh();
        while(currCh && currCh != '"')
        {
            if(currCh == '\\')
            {
                getNextCh();
                switch(currCh)
                {
                case 'n': tkStr += '\n'; break;
                case '"': tkStr += '"'; break;
                case '\\': tkStr += '\\'; break;
                default: tkStr += currCh;
                }
            }
            else
            {
                tkStr += currCh;
            }
            getNextCh();
        }
        getNextCh();
        tk = LEX_STR;
    }
    else if(currCh == '\'')
    {
        // strings again...
        getNextCh();
        while(currCh && currCh != '\'')
        {
            if(currCh == '\\')
            {
                getNextCh();
                switch(currCh)
                {
                case 'n': tkStr += '\n'; break;
                case 'a': tkStr += '\a'; break;
                case 'r': tkStr += '\r'; break;
                case 't': tkStr += '\t'; break;
                case '\'': tkStr += '\''; break;
                case '\\': tkStr += '\\'; break;
                case 'x':
                { // hex digits
                    char buf[3] = "??";
                    getNextCh(); buf[0] = currCh;
                    getNextCh(); buf[1] = currCh;
                    tkStr += (char)strtol(buf, 0, 16);
                } break;
                default: if(currCh >= '0' && currCh <= '7')
                {
                    // octal digits
                    char buf[4] = "???";
                    buf[0] = currCh;
                    getNextCh(); buf[1] = currCh;
                    getNextCh(); buf[2] = currCh;
                    tkStr += (char)strtol(buf, 0, 8);
                }
                         else
                             tkStr += currCh;
                }
            }
            else
            {
                tkStr += currCh;
            }
            getNextCh();
        }
        getNextCh();
        tk = LEX_STR;
    }
    else
    {
        // single chars
        tk = currCh;
        if(currCh) getNextCh();
        if(tk == '=' && currCh == '=')
        { // ==
            tk = LEX_EQUAL;
            getNextCh();
            if(currCh == '=')
            { // ===
                tk = LEX_TYPEEQUAL;
                getNextCh();
            }
        }
        else if(tk == '!' && currCh == '=')
        { // !=
            tk = LEX_NEQUAL;
            getNextCh();
            if(currCh == '=')
            { // !==
                tk = LEX_NTYPEEQUAL;
                getNextCh();
            }
        }
        else if(tk == '<' && currCh == '=')
        {
            tk = LEX_LEQUAL;
            getNextCh();
        }
        else if(tk == '<' && currCh == '<')
        {
            tk = LEX_LSHIFT;
            getNextCh();
            if(currCh == '=')
            { // <<=
                tk = LEX_LSHIFTEQUAL;
                getNextCh();
            }
        }
        else if(tk == '>' && currCh == '=')
        {
            tk = LEX_GEQUAL;
            getNextCh();
        }
        else if(tk == '>' && currCh == '>')
        {
            tk = LEX_RSHIFT;
            getNextCh();
            if(currCh == '=')
            { // >>=
                tk = LEX_RSHIFTEQUAL;
                getNextCh();
            }
            else if(currCh == '>')
            { // >>>
                tk = LEX_RSHIFTUNSIGNED;
                getNextCh();
            }
        }
        else if(tk == '+' && currCh == '=')
        {
            tk = LEX_PLUSEQUAL;
            getNextCh();
        }
        else if(tk == '-' && currCh == '=')
        {
            tk = LEX_MINUSEQUAL;
            getNextCh();
        }
        else if(tk == '+' && currCh == '+')
        {
            tk = LEX_PLUSPLUS;
            getNextCh();
        }
        else if(tk == '-' && currCh == '-')
        {
            tk = LEX_MINUSMINUS;
            getNextCh();
        }
        else if(tk == '&' && currCh == '=')
        {
            tk = LEX_ANDEQUAL;
            getNextCh();
        }
        else if(tk == '&' && currCh == '&')
        {
            tk = LEX_ANDAND;
            getNextCh();
        }
        else if(tk == '|' && currCh == '=')
        {
            tk = LEX_OREQUAL;
            getNextCh();
        }
        else if(tk == '|' && currCh == '|')
        {
            tk = LEX_OROR;
            getNextCh();
        }
        else if(tk == '^' && currCh == '=')
        {
            tk = LEX_XOREQUAL;
            getNextCh();
        }
    }
    /* This isn't quite right yet */
    tokenLastEnd = tokenEnd;
    tokenEnd = dataPos - 3;
}

string CScriptLex::getSubString(int lastPosition)
{
    int lastCharIdx = tokenLastEnd + 1;
    if(lastCharIdx < dataEnd)
    {
        /* save a memory alloc by using our data array to create the
           substring */
        char old = data[lastCharIdx];
        data[lastCharIdx] = 0;
        std::string value = &data[lastPosition];
        data[lastCharIdx] = old;
        return value;
    }
    else
    {
        return std::string(&data[lastPosition]);
    }
}


CScriptLex *CScriptLex::getSubLex(int lastPosition)
{
    int lastCharIdx = tokenLastEnd + 1;
    if(lastCharIdx < dataEnd)
        return new CScriptLex(this, lastPosition, lastCharIdx);
    else
        return new CScriptLex(this, lastPosition, dataEnd);
}

string CScriptLex::getPosition(int pos)
{
    if(pos < 0) pos = tokenLastEnd;
    int line = 1, col = 1;
    for(int i = 0; i < pos; i++)
    {
        char ch;
        if(i < dataEnd)
            ch = data[i];
        else
            ch = 0;
        col++;
        if(ch == '\n')
        {
            line++;
            col = 0;
        }
    }
    char buf[256];
    sprintf_s(buf, 256, "(line: %d, col: %d)", line, col);
    return buf;
}

// ----------------------------------------------------------------------------------- CSCRIPTVARLINK

CScriptVarLink::CScriptVarLink()
{
#if DEBUG_MEMORY
    mark_allocated(this);
#endif 	   
    this->nextSibling = 0;
    this->prevSibling = 0;
    this->var = 0;
    this->owned = false;
    this->name = "";
}

CScriptVarLink::CScriptVarLink(CScriptVar *var, const std::string &name)
{
#if DEBUG_MEMORY
    mark_allocated(this);
#endif
    this->name = name;
    this->nextSibling = 0;
    this->prevSibling = 0;
    this->var = var->ref();
    this->owned = false;
}

CScriptVarLink::CScriptVarLink(const CScriptVarLink &link)
{
    // Copy constructor
#if DEBUG_MEMORY
    mark_allocated(this);
#endif
    this->name = link.name;
    this->nextSibling = 0;
    this->prevSibling = 0;
    this->var = link.var->ref();
    this->owned = false;
}

CScriptVarLink::~CScriptVarLink()
{
#if DEBUG_MEMORY
    mark_deallocated(this);
#endif
	if(var)
		unref(var);
}

CScriptVarLink* CScriptVarLink::replaceWith(CScriptVar *newVar)
{
    CScriptVar *oldVar = var;
	ASSERT(newVar->getRefs() >= 0);
    var = newVar->ref();
	if(oldVar)
		unref(oldVar);
    return this;
}

CScriptVarLink* CScriptVarLink::replaceWith(CScriptVarLink *newVar)
{
    if(newVar)
        replaceWith(newVar->var);
    else
        replaceWith(new CScriptVar());
    return this;
}

int CScriptVarLink::getIntName()
{
    return atoi(name.c_str());
}
void CScriptVarLink::setIntName(int n)
{
    char sIdx[64];
    sprintf_s(sIdx, sizeof(sIdx), "%d", n);
    name = sIdx;
}

void CScriptVarLink::unref(CScriptVar* oldVar)
{
	if(oldVar->getRefs() <= 0)
		TRACE("WARNING: Too many unrefs in variable \'%s\'. Stack may be corrupted.\n", name.c_str());
	else
		oldVar->unref();
}

// ----------------------------------------------------------------------------------- CSCRIPTVAR

CScriptVar::CScriptVar()
{
    refs = 0;
#if DEBUG_MEMORY
    mark_allocated(this);
#endif		
    lastChild = 0;
    firstChild = 0;
    flags = 0;
    jsCallback = 0;
    jsCallbackUserData = 0;
    data = TINYJS_BLANK_DATA;
    intData = 0;
    doubleData = 0;
    executions = 0;
    nativeHandle = 0;
    flags = SCRIPTVAR_UNDEFINED;
}

CScriptVar::CScriptVar(const string &str) : CScriptVar()
{
    flags = SCRIPTVAR_STRING;
    data = str;
}


CScriptVar::CScriptVar(const string &varData, int varFlags) : CScriptVar()
{
    flags = varFlags;
    if(varFlags & SCRIPTVAR_INTEGER)
    {
        intData = strtol(varData.c_str(), 0, 0);
    }
    else if(varFlags & SCRIPTVAR_DOUBLE)
    {
        doubleData = strtod(varData.c_str(), 0);
    }
    else
        data = varData;
}

CScriptVar::CScriptVar(double val) : CScriptVar()
{
    setDouble(val);
}

CScriptVar::CScriptVar(int val) : CScriptVar()
{
    setInt(val);
}

CScriptVar::~CScriptVar(void)
{
#if DEBUG_MEMORY
    mark_deallocated(this);
#endif
    removeAllChildren();
    if(nativeHandle)
        FREELIB(nativeHandle);
}

CScriptVar *CScriptVar::getReturnVar()
{
    return getParameter(TINYJS_RETURN_VAR);
}

void CScriptVar::setReturnVar(CScriptVar *var)
{
    findChildOrCreate(TINYJS_RETURN_VAR)->replaceWith(var);
}


CScriptVar *CScriptVar::getParameter(const std::string &name)
{
    return findChildOrCreate(name)->var;
}

void CScriptVar::addExecution()
{
    // to be honest, it doesn't really matter if this is a function or not;
    // executions could be tracked for things like variable access, basic blocks...
    this->executions++;
}

int CScriptVar::getExecutions()
{
    return this->executions;
}

CScriptVarLink *CScriptVar::findChild(const string &childName)
{
    auto v = children.find(childName);
    if(v != children.end())
        return v->second;
    if(childName == "length" && isArray())
        return new CScriptVarLink(new CScriptVar(getArrayLength()));
    if(childName == "length" && isString())
        return new CScriptVarLink(new CScriptVar((int)getString().size()));
    return 0;
}

CScriptVarLink *CScriptVar::findChildOrCreate(const string &childName, int varFlags)
{
    CScriptVarLink *l = findChild(childName);
    if(l) return l;

    return addChild(childName, new CScriptVar(TINYJS_BLANK_DATA, varFlags));
}

CScriptVarLink *CScriptVar::findChildOrCreateByPath(const std::string &path)
{
    size_t p = path.find('.');
    if(p == string::npos)
        return findChildOrCreate(path);

    return findChildOrCreate(path.substr(0, p), SCRIPTVAR_OBJECT)->var->
        findChildOrCreateByPath(path.substr(p + 1));
}

CScriptVarLink *CScriptVar::addChild(const std::string &childName, CScriptVar *child)
{
    if(isUndefined())
    {
        flags = SCRIPTVAR_OBJECT;
    }
    // if no child supplied, create one
    if(!child)
        child = new CScriptVar();

    CScriptVarLink *link = new CScriptVarLink(child, childName);
    link->owned = true;
    if(!children.empty())
    {
        // can't use a raw replace because that would lead to dropping
        // the pointer on the floor
        CScriptVarLink* oldChild = findChild(childName);
        if(oldChild)
        {
            oldChild->replaceWith(link);
            delete link;
            return oldChild;
        }
        else
        {
            lastChild->nextSibling = link;
            link->prevSibling = lastChild;
            lastChild = link;
            return children[childName] = link;
        }
    }
    else
    {
        lastChild = firstChild = link;
        return children[childName] = link;
    }
}

CScriptVarLink *CScriptVar::addChildNoDup(const std::string &childName, CScriptVar *child)
{
    // if no child supplied, create one
    if(!child)
        child = new CScriptVar();

    // no duplication is the default behavior of addChild now that it uses a map
    return addChild(childName, child);
}

void CScriptVar::removeChild(const std::string &childName, CScriptVar *child, bool throwIfMissing)
{
    CScriptVarLink* link = findChild(childName);
    if(!link && throwIfMissing)
        throw new CScriptException("Removing a non-existant child");
    else if(link)
        removeLink(link);
}

void CScriptVar::removeLink(CScriptVarLink *link)
{
    if(!link) return;
    if(!children.erase(link->name)) // erase() returns 1 if it actually erased something
        throw new CScriptException("Not this variable's link!"); // don't remove a link that's not ours
    if(link->nextSibling)
        link->nextSibling->prevSibling = link->prevSibling;
    if(link->prevSibling)
        link->prevSibling->nextSibling = link->nextSibling;
    if(firstChild == link)
        firstChild = link->nextSibling;
    if(lastChild == link)
        lastChild = link->prevSibling;
    delete link;
}

void CScriptVar::removeAllChildren()
{
    auto it = children.begin();
    while(it != children.end())
    {
        CScriptVarLink* temp = it->second;
        it = children.erase(it);
        delete temp;
    }
    lastChild = 0;
}

CScriptVar *CScriptVar::getArrayIndex(int idx)
{
    char sIdx[64];
    sprintf_s(sIdx, sizeof(sIdx), "%d", idx);
    CScriptVarLink *link = findChild(sIdx);
    if(link) return link->var;
    else return new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_NULL); // undefined
}

void CScriptVar::setArrayIndex(int idx, CScriptVar *value)
{
    char sIdx[64];
    sprintf_s(sIdx, sizeof(sIdx), "%d", idx);
    CScriptVarLink *link = findChild(sIdx);

    if(link)
    {
        if(value->isUndefined())
            removeLink(link);
        else
            link->replaceWith(value);
    }
    else
    {
        if(!value->isUndefined())
            addChild(sIdx, value);
    }
}

int CScriptVar::getArrayLength()
{
    int highest = -1;
    if(!isArray()) return 0;

    // not the biggest fan of this implementation
    for(auto& child : children)
    {
        CScriptVarLink* link = child.second;
        if(isNumber(link->name))
        {
            int val = atoi(link->name.c_str());
            if(val > highest) highest = val;
        }
    }
    return highest + 1;
}

int CScriptVar::getChildren()
{
    return children.size();
}

int CScriptVar::getInt()
{
    /* strtol understands about hex and octal */
    if(isInt()) return intData;
    if(isNull()) return 0;
    if(isUndefined()) return 0;
    if(isDouble()) return (int)doubleData;
    return 0;
}

double CScriptVar::getDouble()
{
    if(isDouble()) return doubleData;
    if(isInt()) return intData;
    if(isNull()) return 0;
    if(isUndefined()) return 0;
    return 0; /* or NaN? */
}

const string &CScriptVar::getString()
{
    /* Because we can't return a string that is generated on demand.
     * I should really just use char* :) */
    static string s_null = "null";
    static string s_undefined = "undefined";
    if(isInt())
    {
        char buffer[32];
        sprintf_s(buffer, sizeof(buffer), "%ld", intData);
        data = buffer;
        return data;
    }
    if(isDouble())
    {
        char buffer[32];
        sprintf_s(buffer, sizeof(buffer), "%f", doubleData);
        data = buffer;
        return data;
    }
    if(isNull()) return s_null;
    if(isUndefined()) return s_undefined;
    // are we just a string here?
    return data;
}

void CScriptVar::setInt(int val)
{
    flags = (flags&~SCRIPTVAR_VARTYPEMASK) | SCRIPTVAR_INTEGER;
    intData = val;
    doubleData = 0;
    data = TINYJS_BLANK_DATA;
}

void CScriptVar::setDouble(double val)
{
    flags = (flags&~SCRIPTVAR_VARTYPEMASK) | SCRIPTVAR_DOUBLE;
    doubleData = val;
    intData = 0;
    data = TINYJS_BLANK_DATA;
}

void CScriptVar::setString(const string &str)
{
    // name sure it's not still a number or integer
    flags = (flags&~SCRIPTVAR_VARTYPEMASK) | SCRIPTVAR_STRING;
    data = str;
    intData = 0;
    doubleData = 0;
}

void CScriptVar::setUndefined()
{
    // name sure it's not still a number or integer
    flags = (flags&~SCRIPTVAR_VARTYPEMASK) | SCRIPTVAR_UNDEFINED;
    data = TINYJS_BLANK_DATA;
    intData = 0;
    doubleData = 0;
    removeAllChildren();
}

void CScriptVar::setArray()
{
    // name sure it's not still a number or integer
    flags = (flags&~SCRIPTVAR_VARTYPEMASK) | SCRIPTVAR_ARRAY;
    data = TINYJS_BLANK_DATA;
    intData = 0;
    doubleData = 0;
    removeAllChildren();
}

bool CScriptVar::equals(CScriptVar *v)
{
    CScriptVar *resV = mathsOp(v, LEX_EQUAL);
    bool res = resV->getBool();
    delete resV;
    return res;
}

CScriptVar *CScriptVar::mathsOp(CScriptVar *b, int op)
{
    CScriptVar *a = this;
    // Type equality check
    if(op == LEX_TYPEEQUAL || op == LEX_NTYPEEQUAL)
    {
        // check type first, then call again to check data
        bool eql = ((a->flags & SCRIPTVAR_VARTYPEMASK) ==
            (b->flags & SCRIPTVAR_VARTYPEMASK));
        if(eql)
        {
            CScriptVar *contents = a->mathsOp(b, LEX_EQUAL);
            if(!contents->getBool()) eql = false;
            if(!contents->refs) delete contents;
        }
        ;
        if(op == LEX_TYPEEQUAL)
            return new CScriptVar(eql);
        else
            return new CScriptVar(!eql);
    }
    // do maths...
    if(a->isUndefined() && b->isUndefined())
    {
        if(op == LEX_EQUAL) return new CScriptVar(true);
        else if(op == LEX_NEQUAL) return new CScriptVar(false);
        else return new CScriptVar(); // undefined
    }
    else if((a->isNumeric() || a->isUndefined()) &&
        (b->isNumeric() || b->isUndefined()))
    {
        if(!a->isDouble() && !b->isDouble())
        {
            // use ints
            int da = a->getInt();
            int db = b->getInt();
            switch(op)
            {
            case '+': return new CScriptVar(da + db);
            case '-': return new CScriptVar(da - db);
            case '*': return new CScriptVar(da*db);
            case '/': return new CScriptVar(da / db);
            case '&': return new CScriptVar(da&db);
            case '|': return new CScriptVar(da | db);
            case '^': return new CScriptVar(da^db);
            case '%': return new CScriptVar(da%db);
            case LEX_EQUAL:     return new CScriptVar(da == db);
            case LEX_NEQUAL:    return new CScriptVar(da != db);
            case '<':     return new CScriptVar(da < db);
            case LEX_LEQUAL:    return new CScriptVar(da <= db);
            case '>':     return new CScriptVar(da > db);
            case LEX_GEQUAL:    return new CScriptVar(da >= db);
            default: throw new CScriptException("Operation " + CScriptLex::getTokenStr(op) + " not supported on the Int datatype");
            }
        }
        else
        {
            // use doubles
            double da = a->getDouble();
            double db = b->getDouble();
            switch(op)
            {
            case '+': return new CScriptVar(da + db);
            case '-': return new CScriptVar(da - db);
            case '*': return new CScriptVar(da*db);
            case '/': return new CScriptVar(da / db);
            case LEX_EQUAL:     return new CScriptVar(da == db);
            case LEX_NEQUAL:    return new CScriptVar(da != db);
            case '<':     return new CScriptVar(da < db);
            case LEX_LEQUAL:    return new CScriptVar(da <= db);
            case '>':     return new CScriptVar(da > db);
            case LEX_GEQUAL:    return new CScriptVar(da >= db);
            default: throw new CScriptException("Operation " + CScriptLex::getTokenStr(op) + " not supported on the Double datatype");
            }
        }
    }
    else if(a->isArray())
    {
        /* Just check pointers */
        switch(op)
        {
        case LEX_EQUAL: return new CScriptVar(a == b);
        case LEX_NEQUAL: return new CScriptVar(a != b);
        default: throw new CScriptException("Operation " + CScriptLex::getTokenStr(op) + " not supported on the Array datatype");
        }
    }
    else if(a->isObject())
    {
        /* Just check pointers */
        switch(op)
        {
        case LEX_EQUAL: return new CScriptVar(a == b);
        case LEX_NEQUAL: return new CScriptVar(a != b);
        default: throw new CScriptException("Operation " + CScriptLex::getTokenStr(op) + " not supported on the Object datatype");
        }
    }
    else
    {
        string da = a->getString();
        string db = b->getString();
        // use strings
        switch(op)
        {
        case '+':           return new CScriptVar(da + db, SCRIPTVAR_STRING);
        case LEX_EQUAL:     return new CScriptVar(da == db);
        case LEX_NEQUAL:    return new CScriptVar(da != db);
        case '<':     return new CScriptVar(da < db);
        case LEX_LEQUAL:    return new CScriptVar(da <= db);
        case '>':     return new CScriptVar(da > db);
        case LEX_GEQUAL:    return new CScriptVar(da >= db);
        default: throw new CScriptException("Operation " + CScriptLex::getTokenStr(op) + " not supported on the string datatype");
        }
    }
    ASSERT(0);
    return 0;
}

void CScriptVar::copySimpleData(CScriptVar *val)
{
    data = val->data;
    intData = val->intData;
    doubleData = val->doubleData;
    flags = (flags & ~SCRIPTVAR_VARTYPEMASK) | (val->flags & SCRIPTVAR_VARTYPEMASK);
}

void CScriptVar::copyValue(CScriptVar *val)
{
    if(val)
    {
        copySimpleData(val);
        // remove all current children
        removeAllChildren();
        // copy children of 'val'
        for(auto& i : val->children)
        {
            CScriptVarLink *child = i.second;
            CScriptVar *copied;
            // don't copy the 'parent' object...
            if(i.first != TINYJS_PROTOTYPE_CLASS)
                copied = child->var->deepCopy();
            else
                copied = child->var;

            addChild(i.first, copied);
        }
    }
    else
    {
        setUndefined();
    }
}

CScriptVar *CScriptVar::deepCopy()
{
    CScriptVar *newVar = new CScriptVar();
    newVar->copySimpleData(this);
    // copy children
    for(auto& i : children)
    {
        CScriptVarLink *child = i.second;
        CScriptVar *copied;
        // don't copy the 'parent' object...
        if(child->name != TINYJS_PROTOTYPE_CLASS)
            copied = child->var->deepCopy();
        else
            copied = child->var;

        newVar->addChild(child->name, copied);
    }
    return newVar;
}

void CScriptVar::trace(string indentStr, const string &name)
{
    TRACE("%s'%s' = '%s' %s\n",
        indentStr.c_str(),
        name.c_str(),
        getString().c_str(),
        getFlagsAsString().c_str());
    string indent = indentStr + " ";
    for(auto& i : children)
    {
        CScriptVarLink *link = i.second;
        link->var->trace(indent, link->name);
    }
}

string CScriptVar::getFlagsAsString()
{
    string flagstr = "";
    if(flags&SCRIPTVAR_FUNCTION) flagstr = flagstr + "FUNCTION ";
    if(flags&SCRIPTVAR_OBJECT) flagstr = flagstr + "OBJECT ";
    if(flags&SCRIPTVAR_ARRAY) flagstr = flagstr + "ARRAY ";
    if(flags&SCRIPTVAR_NATIVE) flagstr = flagstr + "NATIVE ";
    if(flags&SCRIPTVAR_DOUBLE) flagstr = flagstr + "DOUBLE ";
    if(flags&SCRIPTVAR_INTEGER) flagstr = flagstr + "INTEGER ";
    if(flags&SCRIPTVAR_STRING) flagstr = flagstr + "STRING ";
    return flagstr;
}

string CScriptVar::getParsableString()
{
    // Numbers can just be put in directly
    if(isNumeric())
        return getString();
    if(isFunction())
    {
        ostringstream funcStr;
        funcStr << "function (";
        // get list of parameters	
        CScriptVarLink *link = firstChild;
        while(link)
        {
            funcStr << link->name;
            if(link = link->nextSibling) funcStr << ",";
        }
        // add function body
        funcStr << ") " << getString();
        return funcStr.str();
    }
    // if it is a string then we quote it
    if(isString())
        return getJSString(getString());
    if(isNull())
        return "null";
    return "undefined";
}

void CScriptVar::getJSON(ostringstream &destination, const string linePrefix)
{
    if(isObject())
    {
        string indentedLinePrefix = linePrefix + "  ";
        // children - handle with bracketed list
        destination << "{ \n";
        CScriptVarLink *link = firstChild;
        while(link)
        {
            destination << indentedLinePrefix;
            destination << getJSString(link->name);
            destination << " : ";
            link->var->getJSON(destination, indentedLinePrefix);
            if(link = link->nextSibling)
            {
                destination << ",\n";
            }
        }
        destination << "\n" << linePrefix << "}";
    }
    else if(isArray())
    {
        string indentedLinePrefix = linePrefix + "  ";
        destination << "[\n";
        int len = getArrayLength();
        if(len > 10000) len = 10000; // we don't want to get stuck here!

        for(int i = 0; i < len; i++)
        {
            getArrayIndex(i)->getJSON(destination, indentedLinePrefix);
            if(i < len - 1) destination << ",\n";
        }

        destination << "\n" << linePrefix << "]";
    }
    else
    {
        // no children or a function... just write value directly
        destination << getParsableString();
    }
}


void CScriptVar::setCallback(JSCallback callback, void *userdata)
{
    jsCallback = callback;
    jsCallbackUserData = userdata;
}

std::vector<CScriptVarLink*> CScriptVar::orderedChildren()
{
    std::vector<CScriptVarLink*> output;
    CScriptVarLink* v = firstChild;
    while(v)
    {
        output.push_back(v);
        v = v->nextSibling;
    }
    return output;
}

CScriptVar *CScriptVar::ref()
{
    refs++;
    return this;
}

void CScriptVar::unref()
{
	if(refs <= 0)
	{
		std::ostringstream ss;
		// this is risky
		getJSON(ss);
		TRACE("WARNING: Too many unrefs in variable with contents:\n%s\nStack may be corrupted.\n", ss.str().c_str());
	}
    else if((--refs) == 0)
    {
        delete this;
    }
}

int CScriptVar::getRefs()
{
    return refs;
}


// ----------------------------------------------------------------------------------- CSCRIPT

CTinyJS::CTinyJS(int executions_before_compile)
{
    executions_to_compile = executions_before_compile;
    l = 0;
    root = (new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_OBJECT))->ref();
    // Add built-in classes
    stringClass = (new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_OBJECT))->ref();
    arrayClass = (new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_OBJECT))->ref();
    objectClass = (new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_OBJECT))->ref();
    root->addChild("String", stringClass);
    root->addChild("Array", arrayClass);
    root->addChild("Object", objectClass);
    addNative("function " + string(TINYJS_ARRAY_FUNCTION_NAME) + "(argString)", &createArrayNative, this);
    addNative("function " + string(TINYJS_OBJECT_FUNCTION_NAME) + "(argString)", &createObjectNative, this);
    addNative("function " + string(TINYJS_NEW_FUNCTION_NAME) + "(argString)", &keywordNewNative, this);
}

CTinyJS::~CTinyJS()
{
    ASSERT(!l);
    scopes.clear();
    stringClass->unref();
    arrayClass->unref();
    objectClass->unref();
    root->unref();

#if DEBUG_MEMORY
    show_allocated();
#endif
}

void CTinyJS::trace()
{
    root->trace();
}

void CTinyJS::execute(const string &code)
{
    CScriptLex *oldLex = l;
    vector<CScriptVar*> oldScopes = scopes;
    l = new CScriptLex(code);
#ifdef TINYJS_CALL_STACK
    call_stack.clear();
#endif
    scopes.clear();
    scopes.push_back(root);
    try
    {
        bool execute = true;
        while(l->tk) statement(execute);
    }
    catch(CScriptException *e)
    {
        ostringstream msg;
        msg << "Error " << e->text;
#ifdef TINYJS_CALL_STACK
        for(int i = (int)call_stack.size() - 1; i >= 0; i--)
            msg << "\n" << i << ": " << call_stack.at(i);
#endif
        msg << " at " << l->getPosition();
        delete l;
        l = oldLex;

        throw new CScriptException(msg.str());
    }
    delete l;
    l = oldLex;
    scopes = oldScopes;
}

CScriptVarLink CTinyJS::evaluateComplex(const string &code)
{
    CScriptLex *oldLex = l;
    vector<CScriptVar*> oldScopes = scopes;

    l = new CScriptLex(code);
#ifdef TINYJS_CALL_STACK
    call_stack.clear();
#endif
    scopes.clear();
    scopes.push_back(root);
    CScriptVarLink *v = 0;
    try
    {
        bool execute = true;
        do
        {
            CLEAN(v);
            v = base(execute);
            if(l->tk != LEX_EOF) l->match(';');
        } while(l->tk != LEX_EOF);
    }
    catch(CScriptException *e)
    {
        ostringstream msg;
        msg << "Error " << e->text;
#ifdef TINYJS_CALL_STACK
        for(int i = (int)call_stack.size() - 1; i >= 0; i--)
            msg << "\n" << i << ": " << call_stack.at(i);
#endif
        msg << " at " << l->getPosition();
        delete l;
        delete e;
        l = oldLex;

        throw new CScriptException(msg.str());
    }
    delete l;
    l = oldLex;
    scopes = oldScopes;

    if(v)
    {
        CScriptVarLink r = *v;
        CLEAN(v);
        return r;
    }
    // return undefined...
    return CScriptVarLink(new CScriptVar());
}

string CTinyJS::evaluate(const string &code)
{
    return evaluateComplex(code).var->getString();
}

void CTinyJS::parseFunctionArguments(CScriptVar *funcVar)
{
    l->match('(');
    while(l->tk != ')')
    {
        funcVar->addChildNoDup(l->tkStr);
        l->match(LEX_ID);
        if(l->tk != ')') l->match(',');
    }
    l->match(')');
}

void CTinyJS::addNative(const string &funcDesc, JSCallback ptr, void *userdata)
{
    CScriptLex *oldLex = l;
    l = new CScriptLex(funcDesc);

    CScriptVar *base = root;

    l->match(LEX_R_FUNCTION);
    string funcName = l->tkStr;
    if(l->tk == LEX_R_RESERVED)	 /* Allow for the defining of the three special functions */
        l->match(LEX_R_RESERVED);
    else
        l->match(LEX_ID);
    /* Check for dots, we might want to do something like function String.substring ... */
    while(l->tk == '.')
    {
        l->match('.');
        CScriptVarLink *link = base->findChild(funcName);
        // if it doesn't exist, make an object class
        if(!link) link = base->addChild(funcName, new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_OBJECT));
        base = link->var;
        funcName = l->tkStr;
        l->match(LEX_ID);
    }

    CScriptVar *funcVar = new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_FUNCTION | SCRIPTVAR_NATIVE);
    funcVar->setCallback(ptr, userdata);
    parseFunctionArguments(funcVar);
    delete l;
    l = oldLex;

    base->addChild(funcName, funcVar);
}

CScriptVarLink *CTinyJS::parseFunctionDefinition()
{
    // actually parse a function...
    l->match(LEX_R_FUNCTION);
    string funcName = TINYJS_TEMP_NAME;
    /* we can have functions without names */
    if(l->tk == LEX_ID)
    {
        funcName = l->tkStr;
        l->match(LEX_ID);
    }
    CScriptVarLink *funcVar = new CScriptVarLink(new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_FUNCTION), funcName);
    parseFunctionArguments(funcVar->var);
    int funcBegin = l->tokenStart;
    bool noexecute = false;
    block(noexecute);
    funcVar->var->data = l->getSubString(funcBegin);
    return funcVar;
}

/** Handle a function call (assumes we've parsed the function name and we're
 * on the start bracket). 'parent' is the object that contains this method,
 * if there was one (otherwise it's just a normnal function).
 */
CScriptVarLink *CTinyJS::functionCall(bool &execute, CScriptVarLink *function, CScriptVar *parent)
{
    if(execute)
    {
        if(!function->var->isFunction())
        {
            string errorMsg = "Expecting '";
            errorMsg = errorMsg + function->name + "' to be a function";
            throw new CScriptException(errorMsg.c_str());
        }
        if(executions_to_compile && !function->var->isNative() &&
            function->var->getExecutions() >= executions_to_compile)
        {
            // we've executed this function enough to justify compiling it
            compile(function);
        }
        l->match('(');
        // create a new symbol table entry for execution of this function
        CScriptVar *functionRoot = new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_FUNCTION);
        if(parent)
            functionRoot->addChildNoDup("this", parent);
        // grab in all parameters	  
        CScriptVarLink* v = function->var->firstChild;
        while(v)
        {
            CScriptVarLink *value = base(execute);
            if(execute)
            {
                if(value->var->isBasic())
                {
                    // pass by value
                    functionRoot->addChild(v->name, value->var->deepCopy());
                }
                else
                {
                    // pass by reference
                    functionRoot->addChild(v->name, value->var);
                }
            }
            CLEAN(value);
            if(l->tk != ')') l->match(',');
            v = v->nextSibling;
        }
        l->match(')');
        // setup a return variable
        CScriptVarLink *returnVar = NULL;
        // execute function!
        // add the function's execute space to the symbol table so we can recurse
        CScriptVarLink *returnVarLink = functionRoot->addChild(TINYJS_RETURN_VAR);
        scopes.push_back(functionRoot);
#ifdef TINYJS_CALL_STACK
        call_stack.push_back(function->name + " from " + l->getPosition());
#endif

        if(function->var->isNative())
        {
            ASSERT(function->var->jsCallback);
            function->var->jsCallback(functionRoot, function->var->jsCallbackUserData);
            function->var->addExecution(); // might as well keep track, might be useful
        }
        else
        {
            /* we just want to execute the block, but something could
             * have messed up and left us with the wrong ScriptLex, so
             * we want to be careful here... */
            CScriptException *exception = 0;
            CScriptLex *oldLex = l;
            CScriptLex *newLex = new CScriptLex(function->var->getString());
            l = newLex;
            try
            {
                block(execute);
                // because return will probably have called this, and set execute to false
                execute = true;
                // on a successful execution of the body, add one to the execution count
                function->var->addExecution();
            }
            catch(CScriptException *e)
            {
                exception = e;
            }
            delete newLex;
            l = oldLex;

            if(exception)
                throw exception;
        }
#ifdef TINYJS_CALL_STACK
        if(!call_stack.empty()) call_stack.pop_back();
#endif
        scopes.pop_back();
        /* get the real return var before we remove it from our function */
        returnVar = new CScriptVarLink(returnVarLink->var);
        functionRoot->removeLink(returnVarLink);
        delete functionRoot;
        if(returnVar)
            return returnVar;
        else
            return new CScriptVarLink(new CScriptVar());
    }
    else
    {
        // function, but not executing - just parse args and be done
        l->match('(');
        while(l->tk != ')')
        {
            CScriptVarLink *value = base(execute);
            CLEAN(value);
            if(l->tk != ')') l->match(',');
        }
        l->match(')');
        if(l->tk == '{')
        {
            // TODO: why is this here?
            block(execute);
        }
        /* function will be a blank scriptvarlink if we're not executing,
         * so just return it rather than an alloc/free */
        return function;
    }
}

CScriptVarLink *CTinyJS::factor(bool &execute)
{
    if(l->tk == '(')
    {
        l->match('(');
        CScriptVarLink *a = base(execute);
        l->match(')');
        return a;
    }
    if(l->tk == LEX_R_TRUE)
    {
        l->match(LEX_R_TRUE);
        return new CScriptVarLink(new CScriptVar(1));
    }
    if(l->tk == LEX_R_FALSE)
    {
        l->match(LEX_R_FALSE);
        return new CScriptVarLink(new CScriptVar(0));
    }
    if(l->tk == LEX_R_NULL)
    {
        l->match(LEX_R_NULL);
        return new CScriptVarLink(new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_NULL));
    }
    if(l->tk == LEX_R_UNDEFINED)
    {
        l->match(LEX_R_UNDEFINED);
        return new CScriptVarLink(new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_UNDEFINED));
    }
    if(l->tk == LEX_ID || l->tk == LEX_R_RESERVED)
    {
        CScriptVarLink *a = execute ? findInScopes(l->tkStr) : new CScriptVarLink(new CScriptVar());
        //printf("0x%08X for %s at %s\n", (unsigned int)a, l->tkStr.c_str(), l->getPosition().c_str());
        /* The parent if we're executing a method call */
        CScriptVar *parent = 0;

        if(execute && !a)
        {
            /* Variable doesn't exist! JavaScript says we should create it
             * (we won't add it here. This is done in the assignment operator) */
            a = new CScriptVarLink(new CScriptVar(), l->tkStr);
        }
		bool reserved = false;
		int tkst = l->tokenStart;
		if(l->tk == LEX_R_RESERVED)
		{
			reserved = true;
			l->match(LEX_R_RESERVED);
		}
		else
			l->match(LEX_ID);
        while(l->tk == '(' || l->tk == '.' || l->tk == '[')
        {
            if(l->tk == '(')
            { 
				// ------------------------------------- Function Call
                a = functionCall(execute, a, parent);
            }
            else if(l->tk == '.')
            {
				// ------------------------------------- Record Access
				if(reserved)
				{
					ostringstream errorString;
					errorString << "Got " << l->getTokenStr(LEX_R_RESERVED) << " expected " << l->getTokenStr(LEX_ID)
						<< " at " << tkst;
					throw new CScriptException(errorString.str());
				}
                l->match('.');
                if(execute)
                {
                    const string &name = l->tkStr;
                    CScriptVarLink *child = a->var->findChild(name);
                    if(!child)
                        child = findInParentClasses(a->var, name);
                    if(!child)
                        child = a->var->addChild(name);
                    parent = a->var;
                    a = child;
                }
				l->match(LEX_ID);
            }
            else if(l->tk == '[')
            { 
				// ------------------------------------- Array Access
				if(reserved)
				{
					ostringstream errorString;
					errorString << "Got " << l->getTokenStr(LEX_R_RESERVED) << " expected " << l->getTokenStr(LEX_ID)
						<< " at " << tkst;
					throw new CScriptException(errorString.str());
				}
                l->match('[');
                CScriptVarLink *index = base(execute);
                l->match(']');
                if(execute)
                {
                    CScriptVarLink *child = a->var->findChildOrCreate(index->var->getString());
                    parent = a->var;
                    a = child;
                }
                CLEAN(index);
            }
            else ASSERT(0);
        }
        return a;
    }
    if(l->tk == LEX_INT || l->tk == LEX_FLOAT)
    {
        CScriptVar *a = new CScriptVar(l->tkStr,
            ((l->tk == LEX_INT) ? SCRIPTVAR_INTEGER : SCRIPTVAR_DOUBLE));
        l->match(l->tk);
        return new CScriptVarLink(a);
    }
    if(l->tk == LEX_STR)
    {
        CScriptVar *a = new CScriptVar(l->tkStr, SCRIPTVAR_STRING);
        l->match(LEX_STR);
        return new CScriptVarLink(a);
    }
    if(l->tk == '{')
    {
        return new CScriptVarLink(createObject(execute, l));
    }
    if(l->tk == '[')
    {
        return new CScriptVarLink(createArray(execute, l));
    }
    if(l->tk == LEX_R_FUNCTION)
    {
        CScriptVarLink *funcVar = parseFunctionDefinition();
        if(funcVar->name != TINYJS_TEMP_NAME)
            TRACE("Functions not defined at statement-level are not meant to have a name");
        return funcVar;
    }
    if(l->tk == LEX_R_NEW)
    {
        // new -> create a new object
        l->match(LEX_R_NEW);
        CScriptVarLink* objLink = new CScriptVarLink(keywordNew(execute, l));
        objLink->var->unref(); // unref the extra safety ref added in keywordNew()
        return objLink;
    }
    // Nothing we can do here... just hope it's the end...
    l->match(LEX_EOF);
    return 0;
}

CScriptVar* CTinyJS::createObject(bool& execute, CScriptLex* lexer)
{
	CScriptLex* oldLex = l;
	l = lexer;
    CScriptVar *contents = new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_OBJECT);
    /* JSON-style object definition */
    lexer->match('{');
    while(lexer->tk != '}')
    {
        string id = lexer->tkStr;
        // we only allow strings or IDs on the left hand side of an initialisation
        if(lexer->tk == LEX_STR) l->match(LEX_STR);
        else lexer->match(LEX_ID);
        lexer->match(':');
        if(execute)
        {
            CScriptVarLink *a = base(execute);
            contents->addChild(id, a->var);
            CLEAN(a);
        }
        // no need to clean here, as it will definitely be used
        if(lexer->tk != '}') lexer->match(',');
    }

    lexer->match('}');
	l = oldLex;
    return contents;
}

void CTinyJS::createObjectNative(CScriptVar* root, void* userData)
{
    CScriptLex* lexer = new CScriptLex(root->findChild("argString")->var->getString());
    bool execute = true; // how tedious
    root->setReturnVar(((CTinyJS*)userData)->createObject(execute, lexer));
    delete lexer;
}

CScriptVar* CTinyJS::createArray(bool& execute, CScriptLex* lexer)
{
	CScriptLex* oldLex = l;
	l = lexer;
    CScriptVar *contents = new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_ARRAY);
    /* JSON-style array */
    lexer->match('[');
    int idx = 0;
    while(lexer->tk != ']')
    {
        if(execute)
        {
            char idx_str[16]; // big enough for 2^32
            sprintf_s(idx_str, sizeof(idx_str), "%d", idx);

            CScriptVarLink *a = base(execute);
            contents->addChild(idx_str, a->var);
            CLEAN(a);
        }
        // no need to clean here, as it will definitely be used
        if(lexer->tk != ']') lexer->match(',');
        idx++;
    }
    lexer->match(']');
	l = oldLex;
    return contents;
}

void CTinyJS::createArrayNative(CScriptVar* root, void* userData)
{
    CScriptLex* lexer = new CScriptLex(root->findChild("argString")->var->getString());
    bool execute = true; // how tedious
    root->setReturnVar(((CTinyJS*)userData)->createArray(execute, lexer));
    delete lexer;
}

// make sure to unref the return value from this function AFTER
// adding it to a CScriptVarLink
CScriptVar* CTinyJS::keywordNew(bool& execute, CScriptLex* lexer)
{
	CScriptLex* oldLex = l;
	l = lexer;
    CScriptVar *obj = new CScriptVar(TINYJS_BLANK_DATA, SCRIPTVAR_OBJECT);
    // we need to keep a link to our object to prevent it from getting
    // cleaned during the function parsing.
    CScriptVarLink* objLink = new CScriptVarLink(obj);
    if(execute)
    {
        const string &className = lexer->tkStr;
        CScriptVarLink *objClassOrFunc = findInScopes(className);
        if(!objClassOrFunc)
        {
            TRACE("%s is not a valid class name", className.c_str());
            return new CScriptVar();
        }
        lexer->match(LEX_ID);
        if(objClassOrFunc->var->isFunction())
        {
            CLEAN(functionCall(execute, objClassOrFunc, obj));
        }
        else
        {
            obj->addChild(TINYJS_PROTOTYPE_CLASS, objClassOrFunc->var);
            if(l->tk == '(')
            {
                l->match('(');
                l->match(')');
            }
        }
    }
    else
    {
        lexer->match(LEX_ID);
        if(lexer->tk == '(')
        {
            lexer->match('(');
            lexer->match(')');
        }
    }
    // if the refs of our variable ever drop to zero,
    // we end up in a Right Mess. ref() the object so that
    // it doesn't get exploded, then remember to unref it 
    // in the calling code.
    obj->ref();
    CLEAN(objLink);
	l = oldLex;
    return obj;
}

void CTinyJS::keywordNewNative(CScriptVar* root, void* userData)
{
    CScriptLex* lexer = new CScriptLex(root->findChild("argString")->var->getString());
    bool execute = true; // how tedious
    CScriptVar* obj = ((CTinyJS*)userData)->keywordNew(execute, lexer);
    root->setReturnVar(obj);
    obj->unref(); // prevent a memory leak; unref the extra safety ref that was added in keywordNew()
    delete lexer;
}

void CTinyJS::compile(CScriptVarLink* function)
{
    ASSERT(function->var->isFunction());

    // first, build the syntax tree
    ostringstream json;
    json << "function " << function->name << "(";
    // get list of parameters	
    CScriptVarLink *link = function->var->firstChild;
    while(link)
    {
        json << link->name;
        if(link = link->nextSibling) json << ",";
    }
    // add function body
    json << ") " << function->var->getString();
    CScriptSyntaxTree* stree = new CScriptSyntaxTree(json.str());
    stree->parse();

    ofstream outfile;
    outfile.open("jit.cpp", ios::trunc);
    stree->compile(outfile);
    outfile.close();
    // yes, yes, it's a system() call, blah blah blah
#ifdef _MSC_VER
    // ship off the actual compilation to cl.exe
    // this line is a hell of a doozy. it's made longer by the fact that
    // the development environment has to be activated with this bat script.
    // Note that the version hard-coded here uses a D drive and VS Community 2015 RC; tweak to fit
    // your build environment. 
    // Also, without the redirection at the end, two lines of output will be displayed
    // by cl during compile and there appears to be no way to make it compile quietly.
    // Additionally, it doesn't output to err, only stdout, so even if there are errors
    // it doesn't help at all.
    // Once again, it goes without saying that TinyJS.h must be in the same (working) directory
    // as the executable, and Debug\tiny-js.lib must also exist. 
    system((std::string("%comspec% /c \"\"d:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\VC\\vcvarsall.bat\" x86 && cl.exe /nologo /D_USRDLL /D_WINDLL /EHsc /Zi /FI TinyJS.h jit.cpp Debug\\tiny-js.lib /MDd /LDd /link /DLL /OUT:jit.dll /EXPORT:\"") + function->name + "\"\" > nul").c_str());
#else
    // ship off the actual compilation to gcc for now
    // it goes without saying that this only works if the executable
    // has libtinyjs.so and TinyJS.h in its working directory and gcc
    // on PATH.
    system("gcc -g -Wall -D_DEBUG -std=c++11 -fPIC -include TinyJS.h -L./libtinyjs -shared -o jit.so jit.cpp");
#endif
    // open the newly built library
    LIBHANDLE handle = GETLIB(LIBNAME, RTLD_NOW);
    if(!handle)
    {
        TRACE(GETBUILDERROR);
        return;
    }
    JSCallback callback = (JSCallback)GETSYMBOL(handle, function->name.c_str());

	if(!callback)
	{
		TRACE("Unable to get symbol from DLL. It's possible compilation of the JIT-code failed.\n");
		return;
	}

    function->var->setCallback(callback, this);
    function->var->flags |= SCRIPTVAR_NATIVE;
    function->var->nativeHandle = handle;
}

CScriptVarLink *CTinyJS::unary(bool &execute)
{
    CScriptVarLink *a;
    if(l->tk == '!')
    {
        l->match('!'); // binary not
        a = factor(execute);
        if(execute)
        {
            CScriptVar zero(0);
            CScriptVar *res = a->var->mathsOp(&zero, LEX_EQUAL);
            CREATE_LINK(a, res);
        }
    }
    else
        a = factor(execute);
    return a;
}

CScriptVarLink *CTinyJS::term(bool &execute)
{
    CScriptVarLink *a = unary(execute);
    while(l->tk == '*' || l->tk == '/' || l->tk == '%')
    {
        int op = l->tk;
        l->match(l->tk);
        CScriptVarLink *b = unary(execute);
        if(execute)
        {
            CScriptVar *res = a->var->mathsOp(b->var, op);
            CREATE_LINK(a, res);
        }
        CLEAN(b);
    }
    return a;
}

CScriptVarLink *CTinyJS::expression(bool &execute)
{
    bool negate = false;
    if(l->tk == '-')
    {
        l->match('-');
        negate = true;
    }
    CScriptVarLink *a = term(execute);
    if(negate)
    {
        CScriptVar zero(0);
        CScriptVar *res = zero.mathsOp(a->var, '-');
        CREATE_LINK(a, res);
    }

    while(l->tk == '+' || l->tk == '-' ||
        l->tk == LEX_PLUSPLUS || l->tk == LEX_MINUSMINUS)
    {
        int op = l->tk;
        l->match(l->tk);
        if(op == LEX_PLUSPLUS || op == LEX_MINUSMINUS)
        {
            if(execute)
            {
                CScriptVar one(1);
                CScriptVar *res = a->var->mathsOp(&one, op == LEX_PLUSPLUS ? '+' : '-');
                CScriptVarLink *oldValue = new CScriptVarLink(a->var);
                // in-place add/subtract
                a->replaceWith(res);
                CLEAN(a);
                a = oldValue;
            }
        }
        else
        {
            CScriptVarLink *b = term(execute);
            if(execute)
            {
                // not in-place, so just replace
                CScriptVar *res = a->var->mathsOp(b->var, op);
                CREATE_LINK(a, res);
            }
            CLEAN(b);
        }
    }
    return a;
}

CScriptVarLink *CTinyJS::shift(bool &execute)
{
    CScriptVarLink *a = expression(execute);
    if(l->tk == LEX_LSHIFT || l->tk == LEX_RSHIFT || l->tk == LEX_RSHIFTUNSIGNED)
    {
        int op = l->tk;
        l->match(op);
        CScriptVarLink *b = base(execute);
        int shift = execute ? b->var->getInt() : 0;
        CLEAN(b);
        if(execute)
        {
            if(op == LEX_LSHIFT) a->var->setInt(a->var->getInt() << shift);
            if(op == LEX_RSHIFT) a->var->setInt(a->var->getInt() >> shift);
            if(op == LEX_RSHIFTUNSIGNED) a->var->setInt(((unsigned int)a->var->getInt()) >> shift);
        }
    }
    return a;
}

CScriptVarLink *CTinyJS::condition(bool &execute)
{
    CScriptVarLink *a = shift(execute);
    CScriptVarLink *b;
    while(l->tk == LEX_EQUAL || l->tk == LEX_NEQUAL ||
        l->tk == LEX_TYPEEQUAL || l->tk == LEX_NTYPEEQUAL ||
        l->tk == LEX_LEQUAL || l->tk == LEX_GEQUAL ||
        l->tk == '<' || l->tk == '>')
    {
        int op = l->tk;
        l->match(l->tk);
        b = shift(execute);
        if(execute)
        {
            CScriptVar *res = a->var->mathsOp(b->var, op);
            CREATE_LINK(a, res);
        }
        CLEAN(b);
    }
    return a;
}

CScriptVarLink *CTinyJS::logic(bool &execute)
{
    CScriptVarLink *a = condition(execute);
    CScriptVarLink *b;
    while(l->tk == '&' || l->tk == '|' || l->tk == '^' || l->tk == LEX_ANDAND || l->tk == LEX_OROR)
    {
        bool noexecute = false;
        int op = l->tk;
        l->match(l->tk);
        bool shortCircuit = false;
        bool boolean = false;
        // if we have short-circuit ops, then if we know the outcome
        // we don't bother to execute the other op. Even if not
        // we need to tell mathsOp it's an & or |
        if(op == LEX_ANDAND)
        {
            op = '&';
            shortCircuit = !a->var->getBool();
            boolean = true;
        }
        else if(op == LEX_OROR)
        {
            op = '|';
            shortCircuit = a->var->getBool();
            boolean = true;
        }
        b = condition(shortCircuit ? noexecute : execute);
        if(execute && !shortCircuit)
        {
            if(boolean)
            {
                CScriptVar *newa = new CScriptVar(a->var->getBool());
                CScriptVar *newb = new CScriptVar(b->var->getBool());
                CREATE_LINK(a, newa);
                CREATE_LINK(b, newb);
            }
            CScriptVar *res = a->var->mathsOp(b->var, op);
            CREATE_LINK(a, res);
        }
        CLEAN(b);
    }
    return a;
}

CScriptVarLink *CTinyJS::ternary(bool &execute)
{
    CScriptVarLink *lhs = logic(execute);
    bool noexec = false;
    if(l->tk == '?')
    {
        l->match('?');
        if(!execute)
        {
            CLEAN(lhs);
            CLEAN(base(noexec));
            l->match(':');
            CLEAN(base(noexec));
        }
        else
        {
            bool first = lhs->var->getBool();
            CLEAN(lhs);
            if(first)
            {
                lhs = base(execute);
                l->match(':');
                CLEAN(base(noexec));
            }
            else
            {
                CLEAN(base(noexec));
                l->match(':');
                lhs = base(execute);
            }
        }
    }

    return lhs;
}

CScriptVarLink *CTinyJS::base(bool &execute)
{
    CScriptVarLink *lhs = ternary(execute);
    if(l->tk == '=' || l->tk == LEX_PLUSEQUAL || l->tk == LEX_MINUSEQUAL)
    {
        /* If we're assigning to this and we don't have a parent,
         * add it to the symbol table root as per JavaScript. */
        if(execute && !lhs->owned)
        {
            if(lhs->name.length() > 0)
            {
                CScriptVarLink *realLhs = root->addChildNoDup(lhs->name, lhs->var);
                CLEAN(lhs);
                lhs = realLhs;
            }
            else
                TRACE("Trying to assign to an un-named type\n");
        }

        int op = l->tk;
        l->match(l->tk);
        CScriptVarLink *rhs = base(execute);
        if(execute)
        {
            if(op == '=')
            {
                lhs->replaceWith(rhs);
            }
            else if(op == LEX_PLUSEQUAL)
            {
                CScriptVar *res = lhs->var->mathsOp(rhs->var, '+');
                lhs->replaceWith(res);
            }
            else if(op == LEX_MINUSEQUAL)
            {
                CScriptVar *res = lhs->var->mathsOp(rhs->var, '-');
                lhs->replaceWith(res);
            }
            else ASSERT(0);
        }
        CLEAN(rhs);
    }
    return lhs;
}

void CTinyJS::block(bool &execute)
{
    l->match('{');
    if(execute)
    {
        while(l->tk && l->tk != '}')
            statement(execute);
        l->match('}');
    }
    else
    {
        // fast skip of blocks
        int brackets = 1;
        while(l->tk && brackets)
        {
            if(l->tk == '{') brackets++;
            if(l->tk == '}') brackets--;
            l->match(l->tk);
        }
    }

}

void CTinyJS::statement(bool &execute)
{
    if(l->tk == LEX_ID ||
        l->tk == LEX_INT ||
        l->tk == LEX_FLOAT ||
        l->tk == LEX_STR ||
        l->tk == '-')
    {
        /* Execute a simple statement that only contains basic arithmetic... */
        CLEAN(base(execute));
        l->match(';');
    }
    else if(l->tk == '{')
    {
        /* A block of code */
        block(execute);
    }
    else if(l->tk == ';')
    {
        /* Empty statement - to allow things like ;;; */
        l->match(';');
    }
    else if(l->tk == LEX_R_VAR)
    {
        /* variable creation. TODO - we need a better way of parsing the left
         * hand side. Maybe just have a flag called can_create_var that we
         * set and then we parse as if we're doing a normal equals.*/
        l->match(LEX_R_VAR);
        while(l->tk != ';')
        {
            CScriptVarLink *a = 0;
            if(execute)
                a = scopes.back()->findChildOrCreate(l->tkStr);
            l->match(LEX_ID);
            // now do stuff defined with dots
            while(l->tk == '.')
            {
                l->match('.');
                if(execute)
                {
                    CScriptVarLink *lastA = a;
                    a = lastA->var->findChildOrCreate(l->tkStr);
                }
                l->match(LEX_ID);
            }
            // sort out initialiser
            if(l->tk == '=')
            {
                l->match('=');
                CScriptVarLink *var = base(execute);
                if(execute)
                    a->replaceWith(var);
                CLEAN(var);
            }
            if(l->tk != ';')
                l->match(',');
        }
        l->match(';');
    }
    else if(l->tk == LEX_R_IF)
    {
        l->match(LEX_R_IF);
        l->match('(');
        CScriptVarLink *var = base(execute);
        l->match(')');
        bool cond = execute && var->var->getBool();
        CLEAN(var);
        bool noexecute = false; // because we need to be abl;e to write to it
        statement(cond ? execute : noexecute);
        if(l->tk == LEX_R_ELSE)
        {
            l->match(LEX_R_ELSE);
            statement(cond ? noexecute : execute);
        }
    }
    else if(l->tk == LEX_R_WHILE)
    {
        // We do repetition by pulling out the string representing our statement
        // there's definitely some opportunity for optimisation here
        l->match(LEX_R_WHILE);
        l->match('(');
        int whileCondStart = l->tokenStart;
        bool noexecute = false;
        CScriptVarLink *cond = base(execute);
        bool loopCond = execute && cond->var->getBool();
        CLEAN(cond);
        CScriptLex *whileCond = l->getSubLex(whileCondStart);
        l->match(')');
        int whileBodyStart = l->tokenStart;
        statement(loopCond ? execute : noexecute);
        CScriptLex *whileBody = l->getSubLex(whileBodyStart);
        CScriptLex *oldLex = l;
        while(loopCond)
        {
            whileCond->reset();
            l = whileCond;
            cond = base(execute);
            loopCond = execute && cond->var->getBool();
            CLEAN(cond);
            if(loopCond)
            {
                whileBody->reset();
                l = whileBody;
                statement(execute);
            }
        }
        l = oldLex;
        delete whileCond;
        delete whileBody;
    }
    else if(l->tk == LEX_R_FOR)
    {
        l->match(LEX_R_FOR);
        l->match('(');
        statement(execute); // initialisation
        //l->match(';');
        int forCondStart = l->tokenStart;
        bool noexecute = false;
        CScriptVarLink *cond = base(execute); // condition
        bool loopCond = execute && cond->var->getBool();
        CLEAN(cond);
        CScriptLex *forCond = l->getSubLex(forCondStart);
        l->match(';');
        int forIterStart = l->tokenStart;
        CLEAN(base(noexecute)); // iterator
        CScriptLex *forIter = l->getSubLex(forIterStart);
        l->match(')');
        int forBodyStart = l->tokenStart;
        statement(loopCond ? execute : noexecute);
        CScriptLex *forBody = l->getSubLex(forBodyStart);
        CScriptLex *oldLex = l;
        if(loopCond)
        {
            forIter->reset();
            l = forIter;
            CLEAN(base(execute));
        }
        while(execute && loopCond)
        {
            forCond->reset();
            l = forCond;
            cond = base(execute);
            loopCond = cond->var->getBool();
            CLEAN(cond);
            if(execute && loopCond)
            {
                forBody->reset();
                l = forBody;
                statement(execute);
            }
            if(execute && loopCond)
            {
                forIter->reset();
                l = forIter;
                CLEAN(base(execute));
            }
        }
        l = oldLex;
        delete forCond;
        delete forIter;
        delete forBody;
    }
    else if(l->tk == LEX_R_RETURN)
    {
        l->match(LEX_R_RETURN);
        CScriptVarLink *result = 0;
        if(l->tk != ';')
            result = base(execute);
        if(execute)
        {
            CScriptVarLink *resultVar = scopes.back()->findChild(TINYJS_RETURN_VAR);
            if(resultVar)
                resultVar->replaceWith(result);
            else
                TRACE("RETURN statement, but not in a function.\n");
            execute = false;
        }
        CLEAN(result);
        l->match(';');
    }
    else if(l->tk == LEX_R_FUNCTION)
    {
        CScriptVarLink *funcVar = parseFunctionDefinition();
        if(execute)
        {
            if(funcVar->name == TINYJS_TEMP_NAME)
                TRACE("Functions defined at statement-level are meant to have a name\n");
            else
                scopes.back()->addChildNoDup(funcVar->name, funcVar->var);
        }
        CLEAN(funcVar);
    }
	else if(l->tk == LEX_R_RESERVED)
	{
		// need to be able to call the reserved functions because they're used
		// in JIT-code when it calls evaluateComplex(). This could be removed 
		// if the JIT-code is refitted to set up the function call itself.

		// if the reserved word is used incorrectly, this will attempt to match
		// LEX_ID to LEX_R_RESERVED and error out
		CLEAN(base(execute));
		l->match(';');
	}
    else l->match(LEX_EOF);
}

/// Get the given variable specified by a path (var1.var2.etc), or return 0
CScriptVar *CTinyJS::getScriptVariable(const string &path)
{
    // traverse path
    size_t prevIdx = 0;
    size_t thisIdx = path.find('.');
    if(thisIdx == string::npos) thisIdx = path.length();
    CScriptVar *var = root;
    while(var && prevIdx < path.length())
    {
        string el = path.substr(prevIdx, thisIdx - prevIdx);
        CScriptVarLink *varl = var->findChild(el);
        var = varl ? varl->var : 0;
        prevIdx = thisIdx + 1;
        thisIdx = path.find('.', prevIdx);
        if(thisIdx == string::npos) thisIdx = path.length();
    }
    return var;
}

/// Get the value of the given variable, or return 0
const string *CTinyJS::getVariable(const string &path)
{
    CScriptVar *var = getScriptVariable(path);
    // return result
    if(var)
        return &var->getString();
    else
        return 0;
}

/// set the value of the given variable, return trur if it exists and gets set
bool CTinyJS::setVariable(const std::string &path, const std::string &varData)
{
    CScriptVar *var = getScriptVariable(path);
    // return result
    if(var)
    {
        if(var->isInt())
            var->setInt((int)strtol(varData.c_str(), 0, 0));
        else if(var->isDouble())
            var->setDouble(strtod(varData.c_str(), 0));
        else
            var->setString(varData.c_str());
        return true;
    }
    else
        return false;
}

/// Finds a child, looking recursively up the scopes
CScriptVarLink *CTinyJS::findInScopes(const std::string &childName)
{
    for(int s = scopes.size() - 1; s >= 0; s--)
    {
        CScriptVarLink *v = scopes[s]->findChild(childName);
        if(v) return v;
    }
    return NULL;

}

/// Look up in any parent classes of the given object
CScriptVarLink *CTinyJS::findInParentClasses(CScriptVar *object, const std::string &name)
{
    // Look for links to actual parent classes
    CScriptVarLink *parentClass = object->findChild(TINYJS_PROTOTYPE_CLASS);
    while(parentClass)
    {
        CScriptVarLink *implementation = parentClass->var->findChild(name);
        if(implementation) return implementation;
        parentClass = parentClass->var->findChild(TINYJS_PROTOTYPE_CLASS);
    }
    // else fake it for strings and finally objects
    if(object->isString())
    {
        CScriptVarLink *implementation = stringClass->findChild(name);
        if(implementation) return implementation;
    }
    if(object->isArray())
    {
        CScriptVarLink *implementation = arrayClass->findChild(name);
        if(implementation) return implementation;
    }
    CScriptVarLink *implementation = objectClass->findChild(name);
    if(implementation) return implementation;

    return 0;
}