Hi again,
sorry for answering my own post. Should have looked at the documentation
first.
It's as simple as:
val username = User.find(id).choice( Full(_.name) )( Full("User not
found") ).open_!
(not checked for syntax!)
Regards,
Eros
Eros Candelaresi wrote:
> Hi,
>
> I like the getOrElse way of accessing data very much as it allows to
> handle non-existing values with very little code. However, I am still
> looking for a more elegant replacement for this:
>
> val username = User.find(id).getOrElse(User.create.name("User not
> found")).name
>
> Ok, this is very short already. But still it feels wrong to create an
> instance of User (AFAIK a rather expensive operation, especially when
> used while creating lists) when all I need is a string.
>
> How do you guys handle such cases?
>
> Regards,
> Eros
>
>
> David Pollak wrote:
>
>> On Thu, Nov 12, 2009 at 5:53 AM, Ferdinand Chan <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>>
>> David,
>>
>> Thanks for the blog entry and it does a great job in explaining how
>> Option works and how to use it.
>>
>> May I suggest that we add a link to this blog post on Lift Wiki???
>> Correct me if I'm wrong but I think most newbie to Scala / Lift may
>> wonder and puzzle how Box / Option works.
>>
>> I know you're very busy and with your permission, I'm willing to add
>> this to the wiki
>>
>>
>> No permission required. Please add whatever valuable things to the
>> Lift wiki (the one at http://wiki.github.com/dpp/liftweb )
>>
>>
>>
>> Oh, and I think I really need to tweak my mind a bit and start to
>> think in a more functional / scala way
>>
>>
>> Yeah... it's a change in mindset, but I think you'll find the change
>> to be welcome in terms of your own productivity, your ability to read
>> others' code, and overall code stability.
>>
>> Thanks,
>>
>> David
>>
>>
>>
>> Cheers,
>>
>> Ferdinand
>>
>> On Nov 12, 6:55 am, David Pollak <[email protected]
>> <mailto:[email protected]>>
>> wrote:
>> >
>> http://blog.lostlake.org/index.php?/archives/50-The-Scala-Option-clas...
>> >
>> > The for comprehension is your friend.
>> >
>> >
>> >
>> >
>> >
>> > On Wed, Nov 11, 2009 at 2:40 PM, Ferdinand Chan
>> <[email protected] <mailto:[email protected]>> wrote:
>> >
>> > > Wondering what's the normal practice of using a Box. As a Java
>> > > developer, I always want to get the boxed value by a method named
>> > > "Value" like
>> >
>> > > val optionalContent = Full("This is optional")
>> >
>> > > Log.info( " The optional content is " + optionalContent.value)
>> >
>> > > But I know its not a valid way to do so in lift ( same for
>> Option in
>> > > Scala)
>> >
>> > > From the book programming in Scala , there's an example
>> >
>> > > val withDefault: Option[Int] => Int = {
>> > > case Some(x) => x
>> > > case None => 0
>> > > }
>> >
>> > > which suggest the use of match to retrieve the value of the boxed
>> > > content. It make sense to me and I'm totally agree with the
>> advantage
>> > > of using match + option (Box) combination.
>> >
>> > > However, as a newbie to Scala, I'm so tempted to use something
>> > > like .Value to retrieve the box value .
>> >
>> > > So, what's the normal way to use Box ?? Could someone kindly
>> provide
>> > > some example on how to use ? I tried to look through some
>> source code
>> > > of Lift but its not easy for a newbie :)
>> >
>> > > Thanks
>> >
>> > --
>> > Lift, the simply functional web frameworkhttp://liftweb.net
>> <http://liftweb.net>
>> > Beginning Scalahttp://www.apress.com/book/view/1430219890
>> <http://www.apress.com/book/view/1430219890>
>> > Follow me:http://twitter.com/dpp
>> > Surf the harmonics
>>
>>
>>
>>
>> --
>> Lift, the simply functional web framework http://liftweb.net
>> Beginning Scala http://www.apress.com/book/view/1430219890
>> Follow me: http://twitter.com/dpp
>> Surf the harmonics
>>
>>
>
>
> >
>
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