From:             php at richardneill dot org
Operating system: 
PHP version:      6CVS-2008-10-06 (CVS)
PHP Bug Type:     Feature/Change Request
Bug description:  wish: compound logical operators (nand, xor, etc)

Description:
------------
This is a request for a new set of functions, namely the more complex
logical operations, NAND, NOR, XOR, XNOR etc. I suggest implementing them
as functions, rather than as operators, because they can take a variable
number of arguments. These would also be distinct from the bitwise
operators. 

Of course these are pretty trivial to implement oneself as and when
needed, but it would make a small increment of improvement to PHP ;-)

The other advantage is in code-readability. I think that example1 is more
readable than example2:

$example1 = nand ($condition_1, $condition_2, $condition_3, $condition_4)

$example2 = (! ($condition_1 and $condition_2 and $condition3 and
$condition_4)


Thanks for your time and consideration - Richard


Reproduce code:
---------------
A possible implementation:

function nand($a,$b,$c,....){
  #cast everything to boolean
  return !($a and $b and $c ...);
}

function nor($a,$b,$c,...){
  #cast to boolean
  return !($a or $b or $c or ...);
}

function new_and($a,$b,$c,...){
   #note: this makes the syntax much clearer and shorter if
   #there are very many inputs.
   return ($a and $b and $c...);
}

#similarly, new_or()

function xor($a,$b,$c,...){
    $count=0;
    if ($a){ $count++ ;}
    if ($b){ $count++ ;}
    if ($c){ $count++ ;}
    ...
    return ($count == 1);
}

function xnor($a,$b,$c,...){
    $count=0;
    if ($a){ $count++ ;}
    if ($b){ $count++ ;}
    if ($c){ $count++ ;}
    ...
    return ($count != 1);
}

function majority($a,$b,$c,...){
    $count=0;
    if ($a){ $count++ ;}
    if ($b){ $count++ ;}
    if ($c){ $count++ ;}
    ..
    return ($count > $number_of_args/2);
}

#and any others I've missed out.



-- 
Edit bug report at http://bugs.php.net/?id=46239&edit=1
-- 
Try a CVS snapshot (PHP 5.2): 
http://bugs.php.net/fix.php?id=46239&r=trysnapshot52
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Try a CVS snapshot (PHP 6.0): 
http://bugs.php.net/fix.php?id=46239&r=trysnapshot60
Fixed in CVS:                 http://bugs.php.net/fix.php?id=46239&r=fixedcvs
Fixed in release:             
http://bugs.php.net/fix.php?id=46239&r=alreadyfixed
Need backtrace:               http://bugs.php.net/fix.php?id=46239&r=needtrace
Need Reproduce Script:        http://bugs.php.net/fix.php?id=46239&r=needscript
Try newer version:            http://bugs.php.net/fix.php?id=46239&r=oldversion
Not developer issue:          http://bugs.php.net/fix.php?id=46239&r=support
Expected behavior:            http://bugs.php.net/fix.php?id=46239&r=notwrong
Not enough info:              
http://bugs.php.net/fix.php?id=46239&r=notenoughinfo
Submitted twice:              
http://bugs.php.net/fix.php?id=46239&r=submittedtwice
register_globals:             http://bugs.php.net/fix.php?id=46239&r=globals
PHP 4 support discontinued:   http://bugs.php.net/fix.php?id=46239&r=php4
Daylight Savings:             http://bugs.php.net/fix.php?id=46239&r=dst
IIS Stability:                http://bugs.php.net/fix.php?id=46239&r=isapi
Install GNU Sed:              http://bugs.php.net/fix.php?id=46239&r=gnused
Floating point limitations:   http://bugs.php.net/fix.php?id=46239&r=float
No Zend Extensions:           http://bugs.php.net/fix.php?id=46239&r=nozend
MySQL Configuration Error:    http://bugs.php.net/fix.php?id=46239&r=mysqlcfg

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