I agree Scott.
Also... well done! Very cool addition.
On 1/23/06, Scott Hyndman <[EMAIL PROTECTED]> wrote:
> You're right, but SQL is the same way, and you don't see most developers
> complaining.
>
> The other thing is that you can't easily build dynamic queries your way. The
> same problem can be seen in the LINQ demos for C# 3.0.
>
> And you won't lose too much time. ActionStep has very informative exception
> messages throughout. Unlike Macromedia's framework, we make extensive use of
> exceptions to tell you exactly what has gone wrong.
>
> I know there are other ways to do the same thing, but I think there are too
> many benefits here to pass up.
>
> Scott
>
> -----Original Message-----
> From: [EMAIL PROTECTED] on behalf of Nicolas Cannasse
> Sent: Mon 1/23/2006 11:32 AM
> To: Open Source Flash Mailing List
> Cc:
> Subject: Re: [osflash] ActionStep predicate support (for filtering
> arrays)
>
> > Let's say we have an NSArray containing "person" objects structured as
> > follows:
> >
> > {firstName:String, lastName:String, age:Number, canDrive:Boolean}
> >
> > Now, let's say in your application, you allow the users to filter by all
> > sorts of criteria. Suppose you wanted to display all drivers over 60.
> > The predicate string to describe this criteria would be as follows:
> >
> > "canDrive == true AND age >= 60"
> >
> > To actually filter the array, here's what you'd do:
> >
> > var pred:NSPredicate = NSPredicate.predicateWithFormat("canDrive == true
> > AND age >= 60"); var driversOver60:NSArray =
> > people.filteredArrayUsingPredicate(pred);
> >
> > And that's it. Pretty cool, huh?
>
> Yes, but it's fully untyped.
>
> What if you make a typo "candrive" instead of "canDrive" or mistake the
> flag (using "cantDrive"). What if you apply the predicate to the wrong
> Array ? what if you rename one of your objet fields ? All of theses will
> be runtime errors. There are not so bad, but if they happen late in the
> development of your application, they can make you loose significant
> time debugging it.
>
> In haXe for instance, you could be able to fully type it :
>
> class Filter<T> {
>
> static function filterArray(
> pred : T -> Bool,
> arr : Array<T>
> ) : Array<T> {
> var arr2 = new Array();
> var i = 0;
> var l = arr.length;
> while( i < l ) {
> var elt = arr[i];
> if( pred(elt) )
> arr2.push(elt);
> i++;
> }
> return arr2;
> }
>
> }
>
>
> Then you can write your predicate like this :
>
> var pred = function(p : NSPerson) { return p.canDrive && p.age >= 60; };
>
> Also, you're not restricted to some syntax, since you can use the whole
> language as syntax, and even call methods :
>
> var pred = function(p : NSPerson) { return p.birthday() == today; };
>
> You could do the same with MTASC, but with less type checks.
> My two eurocents ;)
>
> Nicolas
>
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>
>
>
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