rewrote generic classes tour #705
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| Like in Java 5 (aka. [JDK 1.5](http://java.sun.com/j2se/1.5/)), Scala has built-in support for classes parameterized with types. Such generic classes are particularly useful for the development of collection classes. | ||
| Here is an example which demonstrates this: | ||
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| ## Defining a generic classes |
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Defining "a generic classes", typo?
| println(stack.pop) // prints 97 | ||
| println(stack.peek) // prints 1 | ||
| ``` | ||
| Here we have a stack of Ints. Notice how we can pass in the Char object `a`. This is because the `Char` class has a [method to implicitly convert a `Char` to an Int](http://scala-lang.org/api/current/scala/Char$.html#char2int(x:Char):Int). |
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Is this worth to be explained here? I think the example adds too much info to the reader, which is assumed to be familiar with implicit conversions. I would just remove the char example 😄.
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| Here is an example which demonstrates this: | ||
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| ## Defining a generic class | ||
| Generic classes take a type as a parameter within square brackets `[]`. One convention is to use the letter `T` as type parameter identifier, though this is not required. |
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though this is not required
This suggests that you may omit the parameter completely, which is not the case.
Perhaps "though any parameter name may be applied".
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In Scala, using A rather than T is the convention for a single parameter.
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@SethTisue - A is ubiquitous in the standard library and in various other locations (IIRC it was the convention used in Programming in Scala, and it is the convention used in Functional Programming in Scala (which I can check despite being away from books because a chapter is available online).
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interesting — thanks. I seem to have been oblivious.
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Perhaps "It's common to use arbitrary letters such as A and B for this."
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| } | ||
| ``` | ||
| This implementation of a `Stack` class takes any type `A` as a parameter. This means the underlying list, `var elements: List[T] = Nil`, can only store elements of type `A`. The procedure `def push` only accepts objects of type `A` (note: `elements = x :: elements` reassigns `elements` to a new list created by prepending `x` to the current `elements`). |
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There's a single typo left (a missed |
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