Hi,
> Why does the function "quotes" (within the class) fail when the exact
> same function "dquote" (outside the class) works fine.
The function's fine; what's happening is that you're trying to use an
undefined symbol (in `doc_name`, `quotes` is undefined). `this` is
*never* implicit in JavaScript the way it is in some other languages,
you have to write it explicitly.
You could fix it by adding "this.":
doc_name: function() { return this.quotes( this.name ); }
...but since `quotes` doesn't need access to any of the instance
properties, there's no reason to put it on the object at all. I'd
probably use a closure instead and make it just a function within the
closure:
var Test_01 = (function() {
function quotes( strStr ) {
return "\"" + strStr + \"";
}
return Class.create( {
initialize: function( strName ) {
this.name = String( strName );
},
doc_name: function() { return quotes( this.name ); }
});
})();
There, I've wrapped up your Class.create call inside an anonymous
function (called a "scoping function") and immediately called the
function. `quotes` ends up being in scope for any code inside the
scoping function, but out of scope for any code outside of it. It
makes `quotes` similar to a private class method in class-based
systems, although the mechanism at work (closures) is rather more
powerful than that. More on closures here:
http://blog.niftysnippets.org/2008/02/closures-are-not-complicated.html
I'd also steer away from using anonymous functions other than as
scoping functions (all of the functions in your Test_01 class are
anonymous); more here:
http://blog.niftysnippets.org/2010/03/anonymouses-anonymous.html
HTH,
--
T.J. Crowder
Independent Software Consultant
tj / crowder software / com
www.crowdersoftware.com
On Jul 14, 4:50 pm, Zortag <[email protected]> wrote:
> I'm pretty new to both JavaScript and Prototype, but have been
> programming for over 30 years, and so this one is causing me to tear
> out what little hair I have left. Basically, I can't seem to figure
> out what is wrong when I move a function that works outside of a class
> into a class, it is a very simple function, just wrap a piece of text
> in double-quotes. But when called from within a class, the script
> blows up and dies. I'm using Firefox, Firebug does see that the class
> has the item and that it is a function; but the script dies as if it
> could not find the function. The JavaScript console remains empty.
>
> Why does the function "quotes" (within the class) fail when the exact
> same function "dquote" (outside the class) works fine. I figure it's
> something simple but it has eluded me.
>
> <html>
> <head>
> <script src="../prototype.js" type="text/javascript"></script>
> </head>
> <body>
> <script type="text/javascript">
> var printp = function( strStr ) { document.write( "<p>" + strStr
> + "</p>" ); };
> var dquote = function( strStr ) { return "\"" + strStr +
> "\""; };
>
> printp( "Begin Test!" );
>
> printp( "Test 1: " + dquote( 'test 1' ) );
>
> var Test_01 = Class.create( {
> initialize: function( strName ) {
> this.name = String( strName );
> },
>
> quotes: function( strStr ) { return "\"" + strStr +
> "\""; },
> doc_name: function() { return quotes( this.name ); }
> });
>
> var test_02 = new Test_01( 'test' );
>
> printp( "Test 2: \"" + test_02.name + "\"" );
> printp( "Test 3: " + test_02.doc_name() );
>
> printp( "End Test!" );
>
> </script>
> </body>
> </html>
--
You received this message because you are subscribed to the Google Groups
"Prototype & script.aculo.us" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/prototype-scriptaculous?hl=en.
