/**
    STCompiler.m
    Bytecode compiler. Generates STExecutableCode from source code.
 
    Copyright (c) 2002 Free Software Foundation
 
    This file is part of the StepTalk project.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#import "STCompiler.h"

#import "STMessage.h"
#import "STLiterals.h"
#import "STBytecodes.h"
#import "STCompiledScript.h"
#import "STCompiledCode.h"
#import "STCompiledMethod.h"
#import "STCompilerUtils.h"
#import "STSourceReader.h"
#import "Externs.h"

#import <StepTalk/STExterns.h>
#import <StepTalk/STScriptObject.h>
#import <StepTalk/STSelector.h>

#import <Foundation/NSArray.h>
#import <Foundation/NSAutoreleasePool.h>
#import <Foundation/NSData.h>
#import <Foundation/NSDebug.h>
#import <Foundation/NSDictionary.h>
#import <Foundation/NSException.h>
#import <Foundation/NSValue.h>
#import <Foundation/NSKeyValueCoding.h>

extern int STCparse(void *context);

/* FIXME: rewrite parser 

    We need three kinds of grammars:

    1. <source> = <statements> | <temp_variables> <statements>

    2. <source> = '[|' <method_list> ']'
       <method_list> = <method> | <method> '!' <method_list>
       <method> =  <statements> | <temp_variables> <statements>

    3. <source> = <method>
       <method> =  <statements> | <temp_variables> <statements>

    Parser 1. are 2. are for scripts. Parser 3. is for script object
    methods. Because majority of the grammar is reused in all three
    parsers we use only one grammar definition. There is no problem
    in haveng 1. and 2. in one file. To be able to have 3. in the same
    file we do a hack: we add a prefix '!!' for method source. Then
    we diferentiate it in grammar file by changin the rule:

        3. <source> = '!' '!' <method>

    See STGrammar.y
*/

@interface STCompiler(STCompilerPrivate)
- (void)compile;
- (void)initializeContext;
- (void)destroyCompilationContext;
- (NSUInteger)indexOfTemporaryVariable:(NSString *)varName;

- (void) initializeCompilationContext;

- (NSDictionary *)exceptionInfo;

- (NSUInteger)addSelectorLiteral:(NSString*)selector;
- (NSUInteger)addLiteral:literal;

- (void)compileMethod:(STCMethod *)method;
- (STCompiledCode *) compileStatements:(STCStatements *)statements;
- (void)compileStatements:(STCStatements *)statements blockFlag:(BOOL)blockFlag;
- (void)compilePrimary:(STCPrimary *)primary;
- (void)compileExpression:(STCExpression *)expr;

- (void)emitPushReceiverVariable:(NSUInteger)index;
- (void)emitPushSelf;
- (void)emitPopAndStoreReceiverVariable:(NSUInteger)index;
- (void)emitReturn;
- (void)emitReturnFromBlock;
- (void)emitPushTemporary:(NSUInteger)index;
- (void)emitPushLiteral:(NSUInteger)index;
- (void)emitPushVariable:(NSUInteger)index;
- (void)emitPopAndStoreTemporary:(NSUInteger)index;
- (void)emitPopAndStoreVariable:(NSUInteger)index ;
- (void)emitPopStack;
- (void)emitSendSelector:(NSUInteger)index argCount:(NSUInteger)argCount;
- (void)emitBlockCopy;
- (void)emitDuplicateStackTop;
- (void)emitJump:(short)offset;
- (void)emitLongJump:(short)offset;
- (void)emitPushNil;
- (void)emitPushTrue;
- (void)emitPushFalse;

- (void)fixupLongJumpAt:(NSUInteger)index with:(short)offset;
- (NSUInteger)currentBytecode;
@end

#define MAX(a,b) (((a)>(b))?(a):(b))

@implementation STCompiler
+ compilerWithEnvironment:(STEnvironment *)env
{
    return AUTORELEASE([[self alloc] initWithEnvironment:env]);
}
- initWithEnvironment:(STEnvironment *)env
{
    if ((self = [self init]) != nil)
        [self setEnvironment:env];

    return self;
}

- init
{
    if ((self = [super init]) != nil)
    {
        arrayLiteralClass     = [NSMutableArray class];
        stringLiteralClass    = [NSMutableString class];
        /* bytesLiteralClass  = [NSMutableData class]; */
        intNumberLiteralClass  = [NSNumber class];
        realNumberLiteralClass = [NSNumber class];
        symbolLiteralClass    = [STSelector class];        
        characterLiteralClass = [NSString class];

        receiverVars = [[NSMutableArray alloc] init];
        namedReferences = [[NSMutableArray alloc] init];
    }
    return self;
}
- (void)dealloc
{
    RELEASE(environment);
    RELEASE(receiverVars);
    RELEASE(namedReferences);
    [super dealloc];
}

- (BOOL)beginScript
{
    if(isSingleMethod)
    {
        [NSException raise:@"STCompilerException"
                    format:@"Script source given for single method"];
        return NO;
    }
    else
    {
        return YES;
    }

}
/* ---------------------------------------------------------------------------
 * Compilation
 * ---------------------------------------------------------------------------
 */

- (void)setEnvironment:(STEnvironment *)env
{
    ASSIGN(environment,env);
}

- (STCompiledMethod *)compileMethodFromSource:(NSString *)aString
                                  forReceiver:(STScriptObject *)receiverObject
{
    STCompiledMethod *result;
    NSString         *hackedSource;
    NSString         *exceptionFmt = @"Syntax error at line %li near '%@', "
                                   @"reason: %@.";


    NSDebugLLog(@"STCompiler", @"Compile method for receiver %@", [receiverObject className]);

    if(!environment)
    {
        [NSException  raise:STCompilerGenericException
                     format:@"Compilation environment is not initialized"];
        return nil;
    }
        
    hackedSource = [@"!!" stringByAppendingString:aString];
    reader = [[STSourceReader alloc] initWithString:hackedSource];
    [receiverVars removeAllObjects];

    receiver = RETAIN(receiverObject);

    isSingleMethod = YES;   
    STParserContextInit(&context,self,reader);
    
    NS_DURING
    {
        // extern int STCdebug;
        // STCdebug = 1;
        STCparse(&context);
    }
    NS_HANDLER
    {
        if ([[localException name] isEqualToString: STCompilerSyntaxException])
        {
            NSString *tokenString;
            NSInteger line;
            
            tokenString = [reader tokenString];
            line = [reader currentLine];

            RELEASE(reader);
            reader = nil;
            
            [NSException  raise:STCompilerSyntaxException
                         format:exceptionFmt,
                                (long)line,
                                tokenString,
                                [localException reason]];
                         
        }
        RELEASE(reader);
        reader = nil;
        [localException raise];
    }
    NS_ENDHANDLER

    RELEASE(reader);
    reader = nil;

    result = AUTORELEASE(resultMethod);
    resultMethod = nil;

    RELEASE(receiver);
    receiver = nil;
    
    return result;
}

- (STCompiledScript *)compileString:(NSString *)aString
{
    NSAutoreleasePool *pool = [NSAutoreleasePool new];
    STCompiledScript *result;
    NSString         *exceptionFmt = @"Syntax error at line %li near '%@', "
                                   @"reason: %@.";


    NSDebugLLog(@"STCompiler", @"Compile string");

    isSingleMethod = NO;

    if(!environment)
    {
        [pool release];
        [NSException  raise:STCompilerGenericException
                     format:@"Compilation environment is not initialized"];
        return nil;
    }
    
    reader = [[STSourceReader alloc] initWithString:aString];
    [receiverVars removeAllObjects];

    STParserContextInit(&context,self,reader);
    
    NS_DURING
    {
        // extern int STCdebug;
        // STCdebug = 1;
        STCparse(&context);
    }
    NS_HANDLER
    {
        if ([[localException name] isEqualToString: STCompilerSyntaxException])
        {
            NSString *tokenString;
            NSInteger line;

            tokenString = RETAIN([reader tokenString]);
            line = [reader currentLine];

            RELEASE(reader);
            reader = nil;

            RETAIN(localException);
            [pool release];

            [NSException  raise:STCompilerSyntaxException
                         format:exceptionFmt,
                                (long)line,
                                AUTORELEASE(tokenString),
                                [AUTORELEASE(localException) reason]];
                         
        }
        RELEASE(reader);
        reader = nil;

        RETAIN(localException);
        [pool release];
        [AUTORELEASE(localException) raise];
    }
    NS_ENDHANDLER

    RELEASE(reader);
    reader = nil;

    [pool release];

    result = AUTORELEASE(resultScript);
    resultScript = nil;
    
    return result;
}

- (void)compileMethod:(STCMethod *)method
{
    STCompiledMethod *compiledMethod;
    STCompiledCode   *code;
    STMessage        *messagePattern;
    
    /* FIXME: unite STCMessage and STMessage */
    messagePattern = (STMessage *)[method messagePattern];
    
    if (!messagePattern)
    {
        messagePattern = [STMessage messageWithSelector:@"_unnamed_method"
                                              arguments:nil];
    }
    else if (![[method statements] returnExpression])
    {
        /* A Smalltalk method (but not plain code) without a return expression
           returns the receiver itself. */
        STCPrimary *selfPrimary = [STCPrimary primaryWithVariable:@"self"];
        STCExpression *returnExpression =
            [STCExpression primaryExpressionWithObject:selfPrimary];
        [[method statements] setReturnExpression:returnExpression];
    }
    
    NSDebugLLog(@"STCompiler", @"Compile method %@", [messagePattern selector]);

    tempVars = [NSMutableArray arrayWithArray:[messagePattern arguments]];

    code = [self compileStatements:[method statements]];
   
    compiledMethod = [STCompiledMethod methodWithCode:code
                                       messagePattern:messagePattern];
                                       
    if (!isSingleMethod)
    {

        if (resultMethod)
        {
            [NSException  raise:@"STCompilerException"
                         format:@"Method is present when compiling a script"];
            return;
        }
        if (!resultScript)
        {
            NSDebugLLog(@"STCompiler",
                        @"Creating script with %lu variables",
                        (unsigned long)[receiverVars count]);

            resultScript = [[STCompiledScript alloc] initWithVariableNames:
                                                                receiverVars];
        }
        [resultScript addMethod:compiledMethod];
    }
    else
    {
        if (resultMethod)
        {
            [NSException  raise:@"STCompilerException"
                         format:@"More than one method compiled for single method request"];
            return;
        }
        if (resultScript)
        {
            [NSException  raise:@"STCompilerException"
                         format:@"Compiled script is present when compiling single method"];
            return;
        }
        resultMethod = RETAIN(compiledMethod);
    }
}

- (STCompiledCode *)compileStatements:(STCStatements *)statements
{
    STCompiledCode    *compiledCode;
#ifdef DEBUG
    NSUInteger         count;
    NSUInteger         i;
#endif
    
    /* FIXME: create another class */
    [self initializeCompilationContext];
    
    NSDebugLLog(@"STCompiler", @"compiling statements");

    tempsSize = tempsCount = [tempVars count];

    [self compileStatements:statements blockFlag:NO];

    NSDebugLLog(@"STCompiler", @"  temporaries %lu stack %lu",
                 (unsigned long)tempsSize,(unsigned long)stackSize);

#ifdef DEBUG
    count = [literals count];

    NSDebugLLog(@"STCompiler", @"  literals count %lu", (unsigned long)count);

    for(i=0;i<count;i++)
    {
        NSDebugLLog(@"STCompiler",
                    @"    %2lu %@",
                    (unsigned long)i, [literals objectAtIndex:i]);
    }

    count = [namedReferences count];
    NSDebugLLog(@"STCompiler",@"  named references count %lu",count);
    for(i=0;i<count;i++)
    {
        NSDebugLLog(@"STCompiler",
                    @"    %lu %@",
                    (unsigned long)i,[namedReferences objectAtIndex:i]);
    }
#endif
    
    compiledCode =
        [[STCompiledCode alloc] initWithBytecodesData:byteCodes
                                             literals:literals
                                     temporariesCount:tempsSize
                                            stackSize:stackSize
                                      namedReferences:namedReferences];

    [self destroyCompilationContext];
    
    return AUTORELEASE(compiledCode);
}

- (STSourceReader *)sourceReader
{
    return reader;
}

/* ---------------------------------------------------------------------------
 * Variables
 * ---------------------------------------------------------------------------
 */

- (NSUInteger)indexOfTemporaryVariable:(NSString *)varName
{
    return [tempVars indexOfObject:varName];
}

- (void)setReceiverVariables:(NSArray *)array
{
    [receiverVars setArray:array];
    [namedReferences addObjectsFromArray:array];
}

- (void)addTempVariable:(NSString *)varName
{
    if([tempVars containsObject:varName])
    {
        [NSException raise:STCompilerGenericException
                    format:@"Multiple definition of temporary variable %@",
                           varName];
    }
    else
    {
        [tempVars addObject:varName];
    }
}

- (NSUInteger)addSelectorLiteral:(NSString*)selector
{
    return [self addLiteral:selector];
}

- (NSUInteger)addLiteral:literal
{
    [literals addObject:literal];
    return [literals count] - 1;
}
- (BOOL)isReceiverVariable:(NSString *)varName
{
    return [receiverVars containsObject:varName];
}
- (NSUInteger)indexOfNamedReference:(NSString *)varName
{
    NSUInteger index;
    
    /* is it receiver or extern variable? */
    index = [namedReferences indexOfObject:varName];
    if(index != NSNotFound)
    {
        return index;
    }
    
    /* try to find receiver variable */
    if(receiver)
    {
        NS_DURING
            /* test whether variable is an ivar s*/
            [receiver valueForKey:varName];
            NSDebugLLog(@"STCompiler", @"New name: receiver variable %@", varName);
            [receiverVars addObject:varName];
        NS_HANDLER
            if([[localException name] isEqualToString:NSUndefinedKeyException])
            {
            NSDebugLLog(@"STCompiler", @"New name: extern %@", varName);
                /* receiver has no such variable */
                [externVars addObject:varName];
            }
            else
            {
                [localException raise];
            }
        NS_ENDHANDLER
    }
    else
    {
        NSDebugLLog(@"STCompiler", @"New name: extern %@ (nil receiver)", varName);
        [externVars addObject:varName];
    }
        
    [namedReferences addObject:varName];

    return [namedReferences indexOfObject:varName];
}


/* ---------------------------------------------------------------------------
 * Compiler internals (called from parser)
 * ---------------------------------------------------------------------------
 */

- (void) initializeCompilationContext
{
    RELEASE(byteCodes);
    RELEASE(literals);
    byteCodes  = [[NSMutableData  alloc] init];
    literals   = [[NSMutableArray alloc] init];
    [externVars removeAllObjects];
    [namedReferences removeAllObjects];
    
    stackSize = stackPos = 0;
    tempsSize = tempsCount = 0;
    bcpos = 0;
}

- (void) destroyCompilationContext
{
    RELEASE(byteCodes);
    RELEASE(literals);
    byteCodes  = nil;
    literals   = nil;
    
    stackSize = stackPos = 0;
    tempsSize = tempsCount = 0;
    bcpos = 0;
}

- (void)compileStatements:(STCStatements *)statements blockFlag:(BOOL)blockFlag
{
    BOOL            first;
    NSEnumerator   *enumerator;
    STBlockLiteral *blockInfo = nil;
    STCExpression  *expr;
    NSArray        *array;
    NSUInteger      tempsSave;           /* stored count of temporaries */
    NSUInteger      stackPosSave  = 0;   /* stored previous stack value */  
    NSUInteger      stackSizeSave = 0;
    NSUInteger      jumpIP = 0; /* location of jump bytecode for later fixup */
    NSUInteger      index;
    NSUInteger      argCount=0;  /* argument count for block context */
        
    NSDebugLLog(@"STCompiler-misc",
                @"  compile statements; blockFlag=%i; tempCount=%lu",
                 blockFlag,(unsigned long)tempsCount);

    tempsSave = tempsCount; /* store value, so we can cleanup array later */
    
    array = [statements temporaries];

    NSDebugLLog(@"STCompiler-misc",@"  temporaries %@", array);

    if (array)
    {
        argCount = [array count];
        for (index=0; index<argCount; index++)
        {
            [self addTempVariable:[array objectAtIndex:index]];
        }

        tempsCount += argCount;
        tempsSize = MAX(tempsSize,tempsCount);
    }

    if (blockFlag)
    {
        
        blockInfo = [[STBlockLiteral alloc] initWithArgumentCount:argCount];

        index = [self addLiteral:blockInfo];
        [self emitPushLiteral:index];
        [self emitBlockCopy];

        jumpIP = [self currentBytecode];

        /* block has its own stack */
        stackPosSave = stackPos;
        stackSizeSave = stackSize;
        stackSize = argCount;
        stackPos = argCount;

        [self emitLongJump:0];
        
        for (index = argCount; index > 0; index--)
        {
            [self emitPopAndStoreTemporary:tempsSave + index - 1];
        }
    }
    
    array = [statements expressions];
    
    first = YES;
    if (array)
    {
        enumerator = [array objectEnumerator];
        while ((expr = [enumerator nextObject]) != nil)
        {
            if (!first)
            {
                [self emitPopStack];
            }
            else 
            {
                first = NO;
            }
            [self compileExpression:expr];
        }
    }

    expr = [statements returnExpression];
    if (expr)
    {
        if (!first)
        {
            [self emitPopStack];
        }
        [self compileExpression:expr];
    }
    else if (first)
    {
	if (blockFlag)
	{
	    [self emitPushNil];
	}
	else
	{
	    [self emitPushSelf];
	}
    }

    if (blockFlag)
    {
        [blockInfo setStackSize:stackSize];
        AUTORELEASE(blockInfo);

        stackSize = stackSizeSave;
        stackPos = stackPosSave;

        if (expr)
        {
            [self emitReturn];
        }
        else
        {
            [self emitReturnFromBlock];
        }
    }
    else
    {
        [self emitReturn];
    }

    /* fixup jump (if block) */
    if (blockFlag)
    {
        [self fixupLongJumpAt:jumpIP with:[self currentBytecode] - jumpIP];
    }

    /* cleanup unneeded temp variables */
//
//    [tempVars removeObjectsInRange:NSMakeRange(tempsSave,
//                                               [tempVars count]-tempsSave)];
//    tempsCount = tempsSave;
    tempsCount = [tempVars count];

    if (blockFlag)
    {
        NSUInteger i;      
        /* Need to keep the block parameters allocated until we exit
           the method context, but we also need to harvest the names*/
        for (i = tempsSave; i < tempsCount; ++i)
            [tempVars  replaceObjectAtIndex: i withObject:@""];
     
    }
    else
    {
        /* cleanup unneeded temp variables */
        [tempVars removeObjectsInRange:NSMakeRange(tempsSave,
                                                   tempsCount-tempsSave)];
        tempsCount = tempsSave;
    }
}

- (void)compilePrimary:(STCPrimary *)primary
{
    id object = [primary object];
    NSUInteger index;

    NSDebugLLog(@"STCompiler-misc",@"  compile primary");

    switch([primary type])
    {
    case STCVariablePrimaryType:
            if([object isEqualToString:@"YES"]
                || [object isEqualToString:@"true"])
            {
                [self emitPushTrue];
            }
            else if([object isEqualToString:@"NO"]
                || [object isEqualToString:@"false"])
            {
                [self emitPushFalse];
            }
            else if([object isEqualToString:@"nil"])
            {
                [self emitPushNil];
            }
            else
            {
                index = [self indexOfTemporaryVariable:object];
                if(index != NSNotFound)
                {
                    [self emitPushTemporary:index];
                    break;
                }
                else if( [object isEqual:@"self"] )
                {
                    [self emitPushSelf];
                    break;
                }
                else
                {
                    index = [self indexOfNamedReference:object];

                    if([self isReceiverVariable:object])
                    {
                        [self emitPushReceiverVariable:index];
                    }
                    else
                    {
                        [self emitPushVariable:index];
                    }
                }
            }
            break;

    case STCLiteralPrimaryType:

            index = [self addLiteral:object];
            [self emitPushLiteral:index];
            break;

    case STCBlockPrimaryType:

            [self compileStatements:object blockFlag:YES];
            break;

    case STCExpressionPrimaryType:

            [self compileExpression:object];
            break;

    default:

            [NSException raise:STCompilerInconsistencyException
                        format:@"Unknown primary type %i", 
                               [primary type]];
            break;
    }
}

- (void)compileMessage:(STCMessage *)message
{
    NSEnumerator *enumerator;
    NSArray      *args;
    id            obj;
    NSUInteger    index;
    
    args = [message arguments];
    if(args && ([args count]>0))
    {
        enumerator = [args objectEnumerator];
        while((obj = [enumerator nextObject]))
        {
            if([obj isKindOfClass:[STCPrimary class]])
                [self compilePrimary:obj];
            else
                [self compileExpression:obj];
        }
    }

    index = [self addSelectorLiteral:[message selector]];
    [self emitSendSelector:index argCount:[args count]];
}

- (void)compileExpression:(STCExpression *)expr
{
    NSEnumerator  *enumerator;
    NSArray       *cascade;
    NSString      *varName;
    NSArray       *array;
    NSUInteger     count;
    NSUInteger     index,i;
    id             obj;
    
    NSDebugLLog(@"STCompiler-misc",@"  compile expression");
    
    if([expr isPrimary])
    {
        [self compilePrimary:[expr object]];
    }
    else /* message expression */
    {
        obj = [expr target];

        /* target */
        if([obj isKindOfClass:[STCPrimary class]])
            [self compilePrimary:obj];
        else
            [self compileExpression:obj];
        
        cascade = [expr cascade];
        if(cascade)
        {
            count = [cascade count];
            for(i=0;i<count;i++)
                [self emitDuplicateStackTop];
        }
        
        [self compileMessage:[expr message]];

        /* cascade expression */
        if(cascade)
        {
            enumerator = [cascade objectEnumerator];
            while( (obj = [enumerator nextObject]) )
            {
                /* ignore previous return value */
                [self emitPopStack];
                [self compileMessage:obj];
            }
        }        
    }

    array = [expr assignments];
    count = [array count];
    if(array && count>0)
    {
        for(i = 0; i<count; i++)
        {
            [self emitDuplicateStackTop];
        }
        
        for(i = 0; i<count; i++)
        {
            varName = [array objectAtIndex:i];

            index = [self indexOfTemporaryVariable:varName];
            if(index != NSNotFound)
            {
                [self emitPopAndStoreTemporary:index];
                continue;
            }
            if( [varName isEqual:@"self"] )
            {
                NSLog(@"Warning: trying to store to self (ignoring)");
                [self emitPopStack];
                continue;
            }
            else
            {
                index = [self indexOfNamedReference:varName];
                if([self isReceiverVariable:varName])
                {
                    [self emitPopAndStoreReceiverVariable:index];
                }
                else
                {
                    [self emitPopAndStoreVariable:index];
                }
            }
        }
    }
}


/* ---------------------------------------------------------------------------
 * Literal classes
 * ---------------------------------------------------------------------------
 */

- (Class)stringLiteralClass
{
    return stringLiteralClass;
}
- (Class)arrayLiteralClass
{
    return arrayLiteralClass;
}
- (Class)intNumberLiteralClass
{
    return intNumberLiteralClass;
}
- (Class)realNumberLiteralClass
{
    return realNumberLiteralClass;
}
- (Class)symbolLiteralClass
{
    return symbolLiteralClass;
}
- (Class)characterLiteralClass
{
    return characterLiteralClass;
}
- (void)setStringLiteralClass:(Class)aClass
{
    stringLiteralClass = aClass;
}
- (void)setArrayLiteralClass:(Class)aClass
{
    arrayLiteralClass = aClass;
}
- (void)setIntNumberLiteralClass:(Class)aClass
{
    intNumberLiteralClass = aClass;
}
- (void)setRealNumberLiteralClass:(Class)aClass
{
    realNumberLiteralClass = aClass;
}
- (void)setSymbolLiteralClass:(Class)aClass
{
    symbolLiteralClass = aClass;
}
- (void)setCharacterLiteralClass:(Class)aClass
{
    characterLiteralClass = aClass;
}

- (id)createIntNumberLiteralFrom:(NSString *)aString
{
    return [intNumberLiteralClass intNumberFromString:aString];
}
- (id)createRealNumberLiteralFrom:(NSString *)aString
{
    return [realNumberLiteralClass realNumberFromString:aString];
}
- (id)createSymbolLiteralFrom:(NSString *)aString
{
    return [symbolLiteralClass symbolFromString:aString];
}
- (id)createStringLiteralFrom:(NSString *)aString
{
    return [stringLiteralClass stringFromString:aString];
}
- (id)createCharacterLiteralFrom:(NSString *)aString
{
    return [characterLiteralClass characterFromString:aString];
}
- (id)createArrayLiteralFrom:(NSArray *)anArray
{
   return [arrayLiteralClass arrayFromArray:anArray];
}

- (NSDictionary *)exceptionInfo
{
    NSDictionary *dict;
    
    dict = [NSDictionary dictionaryWithObjectsAndKeys:
                            [NSNumber numberWithInt:[reader currentLine]], 
                                @"LineNumber", 
                            [reader tokenString], 
                                @"Token",      
                            [NSValue valueWithRange:[reader tokenRange]],
                                @"TokenRange",
                            nil,nil];
    return dict;
}
/* ---------------------------------------------------------------------------
 * Emit bytecodes
 * ---------------------------------------------------------------------------
 */
#define STDebugEmit(bc) \
                NSDebugLLog(@"STCompiler-emit", \
                            @"#%04lx %@", \
                            (unsigned long)(bc).pointer, \
                            STDissasembleBytecode(bc))

#define STDebugEmitWith(bc,object) \
                NSDebugLLog(@"STCompiler-emit", \
                            @"#%04lx %@ (%@)", \
                            (unsigned long)(bc).pointer, \
                            STDissasembleBytecode(bc), \
                            (object))

#define EMIT_SINGLE(bytecode) \
            do { \
                char bc = bytecode; \
                [byteCodes appendBytes:&bc length:1];\
                bcpos++;\
            } while(0)

#define EMIT_DOUBLE(bc1,bc2) \
            do { \
                unsigned char bc[3] = {bc1,0,0}; \
		bc[1] = (unsigned char)((((unsigned short)bc2)>>8)&0xff);\
		bc[2] = (unsigned char)(bc2&0xff); \
                [byteCodes appendBytes:bc length:3];\
                bcpos+=3;\
            } while(0)
#define EMIT_TRIPPLE(bc1,bc2,bc3) \
            do { \
                unsigned char bc[5] = {bc1,0,0,0,0}; \
		bc[1] = (unsigned char)((((unsigned short)bc2)>>8)&0xff);\
		bc[2] = (unsigned char)(bc2&0xff); \
		bc[3] = (unsigned char)((((unsigned short)bc3)>>8)&0xff);\
		bc[4] = (unsigned char)(bc3&0xff); \
                [byteCodes appendBytes:bc length:5];\
                bcpos+=5;\
            } while(0)

#define STACK_PUSH \
            do {\
                stackPos++; \
                stackSize = MAX(stackPos,stackSize);\
                /* NSDebugLLog(@"STCompiler",@"stack pointer %lu/%lu",(unsigned long)stackPos,(unsigned long)stackSize); */\
            } while(0)
#define STACK_PUSH_COUNT(count) \
            do {\
                stackPos+=count; \
                stackSize = MAX(stackPos,stackSize);\
                /* NSDebugLLog(@"STCompiler",@"stack pointer %lu/%lu",(unsigned long)stackPos,(unsigned long)stackSize);*/ \
            } while(0)

#define STACK_POP \
            stackPos--; \
            /* NSDebugLLog(@"STCompiler",@"stack pointer %lu/%lu",(unsigned long)stackPos,(unsigned long)stackSize) */;
#define STACK_POP_COUNT(count) \
            stackPos-=count; \
            /* NSDebugLLog(@"STCompiler",@"stack pointer %lu/%lu",(unsigned long)stackPos,(unsigned long)stackSize) */;
            
- (void)emitPushSelf
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push self", (unsigned long)bcpos);
                
    EMIT_SINGLE(STPushReceiverBytecode);
    STACK_PUSH;
}
- (void)emitPushNil
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push nil", (unsigned long)bcpos);
                
    EMIT_SINGLE(STPushNilBytecode);
    STACK_PUSH;
}
- (void)emitPushTrue
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push true", (unsigned long)bcpos);
                
    EMIT_SINGLE(STPushTrueBytecode);
    STACK_PUSH;
}
- (void)emitPushFalse
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push false", (unsigned long)bcpos);
                
    EMIT_SINGLE(STPushFalseBytecode);
    STACK_PUSH;
}
- (void)emitPushReceiverVariable:(NSUInteger)index
{
                
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push receiver variable %lu (%@)",
                (unsigned long)bcpos,(unsigned long)index,
                [namedReferences objectAtIndex:index]);

    EMIT_DOUBLE(STPushRecVarBytecode,index);
    STACK_PUSH;
}

- (void)emitPushTemporary:(NSUInteger)index
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push temporary %lu (%@)",
                (unsigned long)bcpos,(unsigned long)index,
                [tempVars objectAtIndex:index]);
                
    EMIT_DOUBLE(STPushTemporaryBytecode,index);
    STACK_PUSH;
    
}

- (void)emitPushLiteral:(NSUInteger)index
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push literal %lu (%@)",
                (unsigned long)bcpos,(unsigned long)index,
                [literals objectAtIndex:index]);
                
    EMIT_DOUBLE(STPushLiteralBytecode,index);
    STACK_PUSH;
    stackSize++;
}
- (void)emitPushVariable:(NSUInteger)index
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx push external variable %lu (%@)",
                (unsigned long)bcpos,(unsigned long)index,
                [namedReferences objectAtIndex:index]);
                
    EMIT_DOUBLE(STPushExternBytecode,index);
    STACK_PUSH;
}
- (void)emitPopAndStoreTemporary:(NSUInteger)index
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx pop and store temp %lu (%@)",
                (unsigned long)bcpos,(unsigned long)index,
                [tempVars objectAtIndex:index]);
                
    EMIT_DOUBLE(STPopAndStoreTempBytecode,index);
    STACK_POP;
}
- (void)emitPopAndStoreVariable:(NSUInteger)index
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx pop and store ext variable %lu (%@)",
                (unsigned long)bcpos,(unsigned long)index,
                [namedReferences objectAtIndex:index]);
                
    EMIT_DOUBLE(STPopAndStoreExternBytecode,index);
    STACK_POP;
}
- (void)emitPopAndStoreReceiverVariable:(NSUInteger)index
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx pop and store rec variable %lu (%@)",
                (unsigned long)bcpos,(unsigned long)index,
                [namedReferences objectAtIndex:index]);
                
    EMIT_DOUBLE(STPopAndStoreRecVarBytecode,index);
    STACK_POP;
}

- (void)emitSendSelector:(NSUInteger)index argCount:(NSUInteger)argCount
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx send selector %lu (%@) with %lu args",
                (unsigned long)bcpos,(unsigned long)index,
                [literals objectAtIndex:index],(unsigned long)argCount);
            
    EMIT_TRIPPLE(STSendSelectorBytecode,index,argCount);
    STACK_PUSH_COUNT(argCount);
    STACK_POP_COUNT(argCount);
}
- (void)emitDuplicateStackTop
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx dup",(unsigned long)bcpos);
                
    EMIT_SINGLE(STDupBytecode);
    STACK_PUSH;
}
- (void)emitPopStack
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx pop stack",(unsigned long)bcpos);
                
    EMIT_SINGLE(STPopStackBytecode);
    STACK_POP;
}
- (void)emitReturn
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx return",(unsigned long)bcpos);
                
    EMIT_SINGLE(STReturnBytecode);
}
- (void)emitReturnFromBlock
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx return from block",(unsigned long)bcpos);
                
    EMIT_SINGLE(STReturnBlockBytecode);
}
- (void)emitBlockCopy
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx create block",(unsigned long)bcpos);
                
    EMIT_SINGLE(STBlockCopyBytecode);
}
- (void)emitLongJump:(short)offset
{
    NSDebugLLog(@"STCompiler-emit",
                @"#%04lx long jump %i (0x%04lx)",
                (unsigned long)bcpos,offset,(unsigned long)(bcpos+offset));
                
/*
    EMIT_TRIPPLE(STLongJumpBytecode,STLongJumpFirstByte(offset),
                                    STLongJumpSecondByte(offset));
*/
    EMIT_DOUBLE(STLongJumpBytecode, offset);
}
- (void)fixupLongJumpAt:(NSUInteger)index with:(short)offset
{
    //unsigned char bytes[4] = {0,STLongJumpFirstByte(offset),0,STLongJumpSecondByte(offset)};
    unsigned char bytes[2] = { (offset >> 8) & 0xff, offset & 0xff };

    NSDebugLLog(@"STCompiler-emit",
                @"# fixup long jump at 0x%04lx to 0x%04lx",
                (unsigned long)index, (unsigned long)(index + offset));

    [byteCodes replaceBytesInRange:NSMakeRange(index+1,2) withBytes:bytes];
}
- (NSUInteger)currentBytecode
{
    return [byteCodes length];
}

@end