Webmaster Forum / HTML, CSS, Scripts / JavaScript / April 2005

 Have you considered an array, if element index is sufficient for
 locating the correct value, or an object if you need name:value
 pairs?

 Checking through all the values or printing them out would only
 require a small do..while or for..in loop.

 Here's something to play with, you can add as many variables as you
 like. No doubt some of the loops can be optimised.

 <script type="text/javascript">
 var glob = {
   foo : true,
   bar : true,
   baz : true
    }

 function showGlob(){
 var msg = '';
   for ( varName in glob ){
     msg += '\n' + varName + ' : ' + glob[varName];
   }
  alert(msg);
 }

 function checkTrue() {
 var x = true;
   for ( varName in glob ){
     x = ( x && glob[varName]);
   }
  return x;
 }

 </script>

<input type="button" value="Show vars"
       onclick="showGlob();">
<input type="button" value="Set foo false"
       onclick="glob['foo']=false;">
<input type="button" value="Set foo true"
       onclick="glob['foo']=true;">
<input type="button" value="Check if all true"
       onclick="
         (checkTrue())? alert('All are true'):
             alert('At least one is false');">

JRS:  In article <d4rckb$n29$1@chessie.cirr.com>, dated Thu, 28 Apr 2005
19:13:15, seen in news:comp.lang.javascript, Christopher Benson-Manica
<ataru@nospam.cyberspace.org> posted :

Put them all in an Object, declared as B = {} or with preset contents.
Test them with a function.

function Any(b) { var j
 for (j in b) if (b[j]) return true
 return false }

function All(b) { var j
 for (j in b) if (!b[j]) return false
 return true }

function Umm(b) { var j
 for (j in b) if (!b[j]) return true
 return false }

function Nun(b) { var j
 for (j in b) if (b[j]) return false
 return true }

B = {}
B.foo = 0
B.bar = 1
B.xxx = true
x = [Any(B), All(B), Umm(B), Nun(B)]

You may need a similar but different function.

To store your flags as bits, just use as many integers as you need in an
array to accomodate all the bits.
You can index the relevant integer containing the desired flag thus:
rray[ flagIndex / 32 ] , then just perform a suitable bitwise operation to
read/manipulate the desired bit.

<SCRIPT type='text/javascript'>

function boolManager(boolCount)
{
 this.boolCount=boolCount;
 this.boolStore=[ 1 + boolCount/32 ];
}

boolManager.prototype.readBool=function(ind)
{
 return this.boolStore[ ind/32 ] & 1<<Math.floor(ind % 32);
}

boolManager.prototype.setBool=function(ind, state)
{
 state ? ( this.boolStore[ ind/32 ] |= 1 << ind % 32 )
         : ( this.boolStore[ ind/32 ] &= ~( 1 <<  ind % 32  ) );
}

boolManager.prototype.flipBool=function(ind)
{
 this.boolStore[ ind/32 ] ^= 1 << ind % 32
}

boolManager.prototype.listBools=function()
{
for(var i=0; i<this.boolCount; i++)    // read & display all flags
 document.write('<BR>'+ i + " : " + (this.readBool(i)?"True":"False") );
}

boolManager.prototype.allBoolsFalse=function()
{
 var rv;

 for(var i=0; i<this.boolCount && !(rv=this.readBool(i)) ; i++)
 ;

 return !rv;
}

boolManager.prototype.allBoolsTrue=function()
{
 var rv;

 for(var i=0; i<this.boolCount && (rv=this.readBool(i)) ; i++)
 ;

 return rv;
}

//  =========  Demonstration Code =======

var   boolCount=40, // # of booleans in use
      setFlags=[ 6, 13, 26, 27, 34, 38 ], // some arbitrary booleans to be
set
      myBools=new boolManager(boolCount);

document.write("Set 6, 13, 26, 27, 34 & 38 <BR><BR>");

for(var i=0; i<setFlags.length; i++) // set some booleans to true
myBools.setBool(setFlags[i], true);

myBools.listBools(); // list results

document.write("<BR><BR>Flip all flags :<BR>");

for(var i=0; i<boolCount; i++)  // invert all flags
myBools.flipBool(i);

myBools.listBools();

document.write("<BR><BR>Reset all flags :<BR>");

for(var i=0; i<boolCount; i++)  // reset all flags
myBools.setBool(i, false);

myBools.listBools();

document.write("<BR><BR>Test for all false: " +
(myBools.allBoolsFalse()?"Yes":"No") );

document.write("<BR><BR>Set flag 0 true <BR>");

myBools.setBool(0, true);

document.write("<BR>Test for all false: " +
(myBools.allBoolsFalse()?"Yes":"No") );

document.write("<BR><BR>Set all flags true:<BR>");

for(var i=0; i<boolCount; i++)  // Set all flags
myBools.setBool(i, true);

document.write("<BR>Test for all true: " +
(myBools.allBoolsTrue()?"Yes":"No") );

document.write("<BR><BR>Set flag 20 false <BR>");

myBools.setBool(20, false);

document.write("<BR>Test for all true: " +
(myBools.allBoolsTrue()?"Yes":"No") );

document.write("<BR><BR>Sorted.");

</SCRIPT>

--
Stephen Chalmers        http://makeashorterlink.com/?H3E82245A