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[amibroker] AmiBroker 4.34.2 BETA released



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Hello,
 
A new beta version (4.34.2) of AmiBroker has just been 
released.
 
It is available for registered users only from the members 
area at:
<A 
href="">http://www.amibroker.com/members/bin/ab4342beta.exe
 
If you forgot your user name / password to the members 
area
you can use automatic reminder service at: <A 
href="">http://www.amibroker.com/login.html
 


CHANGES FOR VERSION 
4.34.2 (as compared to 4.34.0)
  improved crash recovery dialog to include AFL engine state information and 
  (in some cases) the source line of the formula that causes an exception 
  added ability to catch all exceptions in indicators and commentaries 
  (switchabel via Tools->Preferences->AFL, "catch system exceptions...", 
  ON by default) - allows you to continue to work even in case of serious 
  problem 
  loop break by Shift+BREAK is now more sensitive 
  now you can control how often Shift+BREAK key is checked during formula 
  execution (Tools->Preferences->AFL, "check SHIFT+Break every" (1..100, 
  default = 50) (note that specifying low values may degrade performance 
  slightly) 
  tweaked AFL memory allocator hash tables to get more speed for large 
  looping formulas 
  although I never reproduced this problem I made some changes so 'TAB' key 
  should not wipe the contents of AFL editor anymore 
Best regards,Tomasz Janeczkoamibroker.com
 

AmiBroker 4.34.2 Beta Read Me
May 3, 2003 21:10 
THIS IS AN EARLY BETA VERSION OF THE SOFTWARE. EXPECT BUGS 
!!!
AGAIN: THIS IS AN EARLY BETA VERSION OF THE SOFTWARE. EXPECT BUGS 
!!!
Backup your data files and entire AmiBroker folder 
first!
INSTALLATION INSTRUCTIONS
IMPORTANT: This archive is update-only. You have to install full 
version 4.30 first. 
Just run the installer and follow the instructions. 
Then run AmiBroker. You should see "AmiBroker 4.34.2 beta" written in the 
About box.
See CHANGE LOG below for detailed list of changes.
HELP ON NEW FEATURES
USER-DEFINABLE FUNCTIONS, PROCEDURES, LOCAL/GLOBAL VARIABLES (4.34 or 
higher)
Here is a sample code showing user-defined function:
// the following function is 2nd order smoother
function IIR2( input, f0, f1, f2 ){  result[ 0 ] = 
input[ 0 ];  result[ 1 ] = input[ 1 ]; 
  for( i = 2; i < BarCount; i++ 
)  {    result[ i ] = f0 * input[ i ] + 
    f1 * result[ i - 1 ] + 
    f2 * result[ i - 2 ];   }
  return result;}
Plot( Close, "Price", colorBlack, styleCandle );Plot( IIR2( Close, 
0.2, 1.4, -0.6 ), "function example", colorRed ); 
In this code IIR2 is a user-defined function. input, f0, f1, 
f2 are formal parameters of the functions.At the time of function call 
the values of arguments are passed in these variables. Formal parameters behave 
like local variables.Later we have result and i which are 
local variables. Local variables are visible inside function only. If any other 
function uses the same variable name they won't interfere between each 
other.
Due to the fact that AFL does not require to declare variables the decision 
whenever given variable is treated as local or global is taken depending on 
where it is FIRST USED.
If given identifier appears first INSIDE function definition - then it is 
treated as LOCAL variable.If given identifier appears first OUTSIDE function 
definition - then it is treated as GLOBAL variable.
Example (commentary):
k = 4; // this is GLOBAL variable
function f( x ){  z = 3; // this is LOCAL 
variable  return z * x * k; // 'k' here references 
global variable k (first used above outside 
function)}
z = 5; // this is GLOBAL variable with the same name as local variable 
in function f
"The value of z before function call :" + WriteVal( z );
// Now even if we call function // the value of our global variable 
z // is not affected by function call because// global variable z and 
local variable z are separate and // arguments are passed by value (not by 
reference)
"The result of f( z ) = " + WriteVal( f( z ) );
"The value of z after function call is unchanged : " + WriteVal( z 
);

At the end of the function we can see 'return' statement that is used to 
return the result to the caller. Note that currently return statement must be 
placed at the very end of the function.
It is also possible to write a procedure (a function that returns nothing 
(void))
procedure SinePlotter( Freq, ColorIndex ){  pname = 
"Line"+WriteVal(ColorIndex,1.0);  array = sin( Cum( Freq * 0.01 ) 
);  Plot( array, pname , colorRed + ColorIndex, styleThick 
);}
for( n = 1; n < 10; n++ ){  SinePlotter( 
n/2+Cum(0.01), n );}
Note that although there are two separate keywords 'function' and 'procedure' 
AmiBroker currently treats them the same (they both accept return values but not 
require them), but in the future the rules maight get enforced to usereturn 
statement ONLY in conjunction with function keyword. So it is advised to use 
function keyword in case when your function returns any value and procedure 
keyword otherwise.
Note also that recursion (having a function call itself from within itself) 
is NOT supported as for now.
FLOW CONTROL AND LOOPING 
(4.31 or higher)
while Statement
The while statement lets you repeat a statement until a specified expression 
becomes false. 
Syntax
while ( expression ) statement
The expression must have arithmetic (numeric/boolean) type. 
Execution proceeds as follows: 

  The expression is evaluated.
  If expression is initially false, the body of the while 
  statement is never executed, and control passes from the while 
  statement to the next statement in the program. 
  If expression is true (nonzero), the body of the statement 
  is executed and the process is repeated beginning at step 1.
This is an example of the while statement: i = 10;while( i < 20 ){  Plot( MA( Close, i ), "MA" + WriteVal( i, 0 ), colorBlack + i );  i = i + 1;}
The example plots 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 - 
bar moving averages.

  
for Statement


The for statement lets you repeat a statement or compound statement a 
specified number of times. The body of a for statement is executed zero 
or more times until an optional condition becomes false.  
Syntax
for ( init-expression ; cond-expression 
; loop-expression ) statement 
Execution of a for statement proceeds as follows: 

  The init-expression, is evaluated. This specifies the 
  initialization for the loop. There is no restriction on the type of 
  init-expression.
  The cond-expression,  is evaluated. This expression must have 
  arithmetic type. It is evaluated before each iteration. Three results are 
  possible: 
  
    If cond-expression is true (nonzero), statement is 
    executed; then loop-expression, if any, is evaluated. The 
    loop-expression is evaluated after each iteration. There is no 
    restriction on its type. Side effects will execute in order. The process 
    then begins again with the evaluation of cond-expression.
    If cond-expression is false (0), execution of the for 
    statement terminates and control passes to the next statement in the 
    program. 
This example illustrates the for statement:  myema[ 0 ] = Close[ 0 ];for( i = 1; i < BarCount; i++ ){   myema[ i ] = 0.1 * Close[ i ] + 0.9 * myema[ i - 1 ];}This example iterates all bars of close array to calculate exponential moving average

if, else Statements
if( expression )statement1 [else 
statement2]
The if keyword executes statement1 if expression is true 
(nonzero); if else is present and expression is false (zero), it 
executes statement2. After executing statement1 or 
statement2, control passes to the next statement.
Example 1if ( i > 0 )
    y = x / i;
else 
{
    x = i;
    y = abs( x );
}
In this example, the statement y = x/i; is executed if 
i is greater than 0. If i is less than or equal to 0, 
i is assigned to x and <FONT 
face="Courier New">abs( x ) is assigned to y. 
Note that the statement forming the if clause ends with a semicolon.
When nesting if statements and else clauses, use braces to 
group the statements and clauses into compound statements that clarify your 
intent. If no braces are present, the compiler resolves ambiguities by 
associating each else with the closest if that lacks an 
else. 
Example 2if ( i > 0 )           /* Without braces */
    if ( j > i )
        x = j;
    else
        x = i;
The else clause is associated with the inner if statement in 
this example. If i is less than or equal to 0, no value is assigned 
to x.
Example 3if ( i > 0 ) 
{                      /* With braces */
    if ( j > i )
        x = j;
}
else
    x = i;
The braces surrounding the inner if statement in this example make the 
else clause part of the outer if statement. If i is 
less than or equal to 0, i is assigned to x. 
CHANGE LOG

CHANGES FOR VERSION 
4.34.2 (as compared to 4.34.0)
  improved crash recovery dialog to include AFL engine state information and 
  (in some cases) the source line of the formula that causes an exception 
  added ability to catch all exceptions in indicators and commentaries 
  (switchabel via Tools->Preferences->AFL, "catch system exceptions...", 
  ON by default) - allows you to continue to work even in case of serious 
  problem 
  loop break by Shift+BREAK is now more sensitive 
  now you can control how often Shift+BREAK key is checked during formula 
  execution (Tools->Preferences->AFL, "check SHIFT+Break every" (1..100, 
  default = 50) (note that specifying low values may degrade performance 
  slightly) 
  tweaked AFL memory allocator hash tables to get more speed for large 
  looping formulas 
  although I never reproduced this problem I made some changes so 'TAB' key 
  should not wipe the contents of AFL editor anymore 
CHANGES FOR VERSION 
4.34.0 (as compared to 4.33.0)
  user-definable functions 
  and procedures with parameters and local variables 
  'A' is NO LONGER 
  predefined symbol. I decided to remove it because people tend to use A as 
  user-variable forgetting the fact that it was build-in array holding typical 
  price (H+L+C)/3. Use 'Avg' instead.
  indicator list column width increased in Indicator Builder 
  DayOfYear - returns the calendar day number counting from beginning of the 
  year January 1st is 1. Maximum number returned is 366 
CHANGES FOR VERSION 
4.33.0 (as compared to 4.32.2)
  Database purify tool implemented (available via Tools->Database 
  Purify)allows to detect missing/extra quotes, possible splits, invalid 
  OHLC relationshipApply to/range settings similar to AA window. You can 
  also right click over result list to add symbols to watch list and copy the 
  list to the clipboard (and paste it later to any other program for futher 
  use)
  further improvements to AFL garbage collector, now looping regardless of 
  loop count requires the same amount of memory as just single pass of the code 
  (no growing allocated memory during loops).This enormously lowered memory 
  consumption for some formulas and increased the speed of some loops 3..4 
  times.
  added variable period support to the following 
  functions:LinRegSlope,LinearReg,LinRegIntercept,StdErr,TSF 

  Sample code:
  Plot( Close, "Test", colorBlack );
  range = 15 * MA( ATR( 15 ), 50 ) / ATR( 15 ); 
  //Plot( range, "range", colorBlue, styleOwnScale );Plot( LinearReg( 
  Close, range ), "Test", colorRed );
  
  fixed sometimes incorrect output of variable-period version of LLV/HHV
  
  fixed crash occuring when bad arguments were passed to the function (bug 
  introduced in 4.32.x).
CHANGES FOR VERSION 
4.32.2 (as compared to 4.32.1)
  second bug in experimental garbage collector fixed. 
CHANGES FOR VERSION 
4.32.1 (as compared to 4.32.0)
  garbage collector was releasing memory too soon in some cases, now fixed. 
  
CHANGES FOR VERSION 
4.32.0 (as compared to 4.31.1)
  added type check in IF/ELSE statements 
  added type check in array element assignment 
  error messages now numbered and display changed slightly 
  you can break running loop by pressing Shift+BREAK (Pause) key combination 

  calling COM objects works again (was broken in 4.31.x) 
  changed slightly the way TAB works in editor, if TAB is pressed any 
  selection is deselected to avoid accidential deletion of text 
  experimental: added 'agressive garbage collector' that extremely 
  decreases the amountof memory required to run AFL formula by releasing the 
  memoryused for temporary variables as soon as possible 
  (previouslytemporary memory was released at the end of formula 
  execution).A side-effect of new garbage collector is some speed up in 
  formula execution. 
  new tab in preferences for AFL engine settings 
  experimental feature, NOT for beginners, may be removed/modified in 
  future releases: new _TRACE( "string" ) AFL function addedthat 
  allows to write debug messages from AFL code to system debug viewer.(it 
  calls internally OutputDebugString Win API function).To view debug 
  messages you have to run DebugView freeware program from 
  http://www.sysinternals.com/ 
CHANGES FOR VERSION 
4.31.1 (as compared to 4.31.0)
  fixed bug introduced in 4.31.0 causing no text output in 
  commentary/interpretation 
CHANGES FOR VERSION 
4.31.0 (as compared to 4.30.0)
  Workspace window uses "icon font" set in the Windows settings instead of 
  hard coded Tahoma 8 
  for better readability and ClearType(tm) compatibility on WinXP, all 
  dialog windows use now 'MS Shell Dlg' face name that maps to standard MS Sans 
  Serif on Win 9x/Me/NT and Tahoma on Win 2K and XP. 
  rewritten AFL parser, now formula is parsed and coverted to syntax tree 
  and then interpreted. This would allow further improvements including 
  compilation. This allowed also to add loops/if-else statements. 
  implemented IF/ELSE statement, WHILE and FOR loops:The same basic 
  'for' loop in AFL is 2..3 times faster than in JScriptSyntax follows 
  C++/JScript style: 
  while( conditional_expression ) statement;
  for( initializer_part; conditional_expression; iterator_part ) 
  statement;
  if( conditional_expression ) statement;
  if( conditional_expression ) 
statement;elsestatement;
  
  implemented compound statements: these are blocks of statements 
  enclosedin opening and closing curly brace 
  {statement1;statement2;...statementN;}
  compound statement can appear anywhere when simple statement can.
  For example:
  i = 10;while( i < 20 ){Plot( MA( Close, i ), "MA" + 
  WriteVal( i, 0 ), colorBlack + i );i = i + 1;}
  
  implemented C-style postfix and prefix increment/decrement operators
  i = 10;WriteIf( i++ );WriteIf( ++i );WriteIf( i 
  );
  
  implemented array element access (subscript) operator []:
  WriteVal( Close[ 0 ] ); // prints the first bar of close 
  array
  /* a sample low-level implementation of exponential moving average in 
  AFL */
  myema[ 0 ] = Close[ 0 ];
  for( i = 1; i < BarCount; i++ ){myema[ i ] = 0.1 * Close[ 
  i ] + 0.9 * myema[ i - 1 ];}
  
  added built-in constant 'BarCount' that returns number of bars available in 
  arrays (the number of elements of array)When QuickAFL is turned on it may 
  be less than true number of bars because QuickAFL feature attempts to use only 
  visible bars (and few before). You can control how many bars the formula 
  requires using SetBarsRequired() function
  
  implemented infinite-loop protection. Nice if you forgot to increment 
  counter variable in 'for' loop :-)
  
  tab key now works without need to press ALT/CTRL in AFL editors
  
  added C-like synonyms for logical ADD/OR/NOT: &&, ||, ! 
  /* a sample low-level implementation of Profit-target stop in 
  AFL: */
  Buy = Cross( MACD(), Signal() );
  priceatbuy=0;
  for( i = 0; i < BarCount; i++ 
  ){     if( priceatbuy == 0 && Buy[ i 
  ] )      priceatbuy = BuyPrice[ i ];
       if( priceatbuy > 0 && 
  SellPrice[ i ] > 1.1 * priceatbuy 
  )     {       Sell[ 
  i ] = 1;       SellPrice[ i ] = 1.1 * 
  priceatbuy;       priceatbuy = 
  0;     }     else       Sell[ 
  i ] = 0;}
  /* sample EMA rainbow */
  Plot( Close, "Price", colorBlack, styleCandle );for( Range = 15; 
  Range < 100; Range++ )   Plot( EMA( Close, Range ), 
  "MA"+WriteVal(Range,0), colorRose + Range % 8, styleNoLabel );
  
HOW TO REPORT BUGS
If you experience any problem with this beta version please send detailed 
description of the problem (especially the steps needed to reproduce it) to <A 
href="">bugs@xxxxxxxxxxxxx 






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