An array of function pointers

[Fotiman]

What I want is a JavaScript object that has an array of JavaScript function calls. I can do this if the functions don't have any parameters, but haven't yet figured out how to do it for functions that take parameters. For example:

function myObj()
{
 function add(f)
 {
 var fcall = f;
 if( typeof f!= "function" )
 {
  fcall = new Function(f);
 }
 this.funcs[this.funcs.length] = fcall;
 }
 function execute()
 {
 for( var i = 0; i < this.funcs.length; i++ )
 {
  this.funcs[i](); // Call the function
 }
 }
 this.funcs = new Array();
 this.add = add;
 this.execute = execute;
}

function hello()
{
 alert("hello");
}
var foo = new myObj();
foo.add(hello);
foo.execute();

However, suppose I have this function:

function goodbye( name )
{
 alert( "Goodbye " + name );
}

How can I add that?

[Bernard Marx]

How can I add that?

You can add it, but how would you like to specify the argument when it is called?

You call the series of functions like this:

foo.execute();

..but since you don't know what position in the array the function requiring an argument is, you can't specify it. We need a little more information from your good self.

I have messed around with you code a little..
(Changed the constructor function to 'FnArray')

- Avoid defining the methods inside the constructor. This is inneficient, and causes closures (although they're fun too). These methods can be inherited via prototype.

- There is a branch in the 'add' method for defining a function if a string is passed instead of a function (I assumed). The little wiggle with the variable 'fcall' wasn't needed. I have added such a call.

function FnArray()
{
    this.funcs = new Array;
}
FnArray.prototype.add = function(f)
{
    if( typeof f!= "function" )
    {
        f = new Function(f);
    }
    this.funcs[this.funcs.length] = f;
}
FnArray.prototype.execute = function()
{
    for( var i=0; i<this.funcs.length; i++ )
    {
        this.funcs[i]();
    }
}
function hello(){ alert("hello"); }
function goodbye( name ){ alert( "Goodbye " + name ); }
var foo = new FnArray();
foo.add(hello);
foo.add("alert('function from string')");
foo.execute();

[Fotiman]

You can add it, but how would you like to specify the argument when it is called?

I'm thinking of something along the lines of this:

var foo = new myObj();
foo.add(hello);
foo.add(goodbye("Peter")); // That won't work though
foo.execute();

In other words, the argument(s) would be included when the function was added. Also, ideally, it would be dynamic such that I could have any number of arguments, or none at all.

Any ideas?

[Bernard Marx]

Yes. Wrap it in a function:

foo.add( [blue]function(){[/blue] goodbye("Peter")[blue]}[/blue] );

[Bernard Marx]

It's also possible using the "string option", but there can be differences (Using the function wrap is probably more flexible).

function goodbye(name){ alert("goodbye "+name); }
function someFunction()
{
    var aName = "Eric Local"
    foo.add( function(){ goodbye(aName)} );
    foo.add( "goodbye(aName)" );
}
var aName = "Paul Global"
var foo = new FnArray();
someFunction()
foo.execute();

[Fotiman]

Ooh, I like that! :) Thanks!