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POIs it possible to get access to the Manifest when initialising a val inside a trait that uses generics?
 

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  1. POIs it possible to get access to the Manifest when initialising a val inside a trait that uses generics?
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    <p>What I'm trying to do (this is a simplified example, but contains all I need)</p> <pre><code>trait MyTrait[T] { val name = Somefunction(simpleName) def simpleName(implicit m:Manifest[T]) = m.erasure.getSimpleName } </code></pre> <p>But I get a "No Manifest available for T" compiler error on the val initialisation at simpleName.</p> <p>doing</p> <pre><code>val name = Somefunction(implicitly[Manifest[T]].erasure.getSimpleName) </code></pre> <p>does the same</p> <p>Somefunction returns a object that is expensive to create, so I only want to create it once.</p> <p>The only way I got this to work is by using a function that checks if the object has already been created and if so then just return it else create it first and then return it.</p> <p><strong>EDIT -- added example of how I can get it to work</strong></p> <p>example</p> <pre><code>trait MyTrait[T] { var n:MyClass = null def name(implicit m:Manifest[T]) = { if(n == null) n = Somefunction(implicitly[Manifest[T]].erasure.getSimpleName) n } } </code></pre>
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    1. USmonkey_p
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    1. COThe example is not at all equivalent to your original desire; because you have to call the `name` method on an instance of the `trait`
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      1. USoxbow_lakes
    2. COALso this will create an instance of Manifest[T] every time you call `name`, although you only need it once.
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      1. USdrexin
    3. CO@oxbow_lakes The `name` method gets called from other methods inside the trait. The object that gets extended with the trait is an empty object. @drexin Yes, that is why I was looking for a way to initialise a `val`
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      1. USmonkey_p
 

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