#850:Tuples page added to tour #1144

mghildiy · 2018-09-12T17:46:03Z

No description provided.

jvican · 2018-09-14T07:29:42Z

I'd like to review this soon, but it looks like I'm all busy until the end of next week. @mghildiy Could you post to Scala Contributors asking for reviewers for this PR?

mghildiy · 2018-09-14T08:18:22Z

Ok.

adriaanm

Thank you! I left a few suggestions.

adriaanm · 2018-09-14T08:43:22Z

_tour/tuples.md

+## Accessing the elements
+
+Tuple elements are accessed using underscore syntax.
+tuple._n gives nth element(given there are that many elements).


Quote as: tuple._n

adriaanm · 2018-09-14T08:45:18Z

_tour/tuples.md

+println(ingredient._2) // 25
+```
+
+## Iterating a tuple


Before you get to productIterator, which I think is a bit of a corner case, I'd show destructuring using patterns. Right now, you have shown how to do this in local vals, but the same applies to pattern matching (x match { case (a,b) => ...), function literals ({ case (a, b) => a + b }), and for comprehensions (for ( (a, b) <- pairs ) ...).

adriaanm · 2018-09-14T08:47:02Z

_tour/tuples.md

+ingredient.toString // (Sugar,25)
+```
+
+Scala tuple also supports destructuring.


bump this to a ## header.

PS: I think it's kind of neat to mention that () is conceptually Tuple0, or Unit. There can only be one value of this type since it has no elements.

Maybe one final comment: you should use case classes whenever the elements have more meaning.

adriaanm · 2018-09-14T08:47:51Z

_ko/tour/mixin-class-composition.md

@@ -10,7 +10,7 @@ num: 6
 language: ko

 next-page: higher-order-functions
-previous-page: traits
+previous-page: tuples
 ---

 _단일 상속_ 만을 지원하는 여러 언어와는 달리, 스칼라는 더욱 일반화된 시각에서 클래스를 재사용한다. 스칼라는 새로운 클래스를 정의할 때 _클래스의 새로운 멤버 정의_ (즉, 슈퍼클래스와 비교할 때 변경된 부분)를 재사용할 수 있다. 이를 _믹스인 클래스 컴포지션_ 이라고 부른다. 이터레이터를 추상화한 다음 예제를 살펴보자.


This should be replaced by the stub to indicate it hasn't been translated yet.

There is some translation there, not sure though if it corresponds to English version.

My mistake, I got confused by the fact that this page is actually about mixins, and it's just the "previous" pointer that's being updated.

adriaanm · 2018-09-14T08:47:59Z

_pt-br/tour/mixin-class-composition.md

@@ -8,7 +8,7 @@ partof: scala-tour

 num: 5
 next-page: higher-order-functions
-previous-page: traits
+previous-page: tuples
 language: pt-br
 ---
 _Nota de tradução: A palavra `mixin` pode ser traduzida como mescla, porém é preferível utilizar a notação original_


This should be replaced by the stub to indicate it hasn't been translated yet.

There is an explanation, but it does not correspond to the English version of the page.

Ah sorry, I got confused by the fact that this page is actually about mixins, and it's just the "previous" pointer that's being updated.

_tour/tuples.md

Jasper-M · 2018-09-14T08:51:59Z

_tour/tuples.md

+In Scala, a tuple is a class that can hold elements of different types.
+Tuples are immutable.
+
+Tuples come handy when we have to return multiple values from a function.


come in handy

Jasper-M · 2018-09-14T08:53:11Z

_tour/tuples.md

+```tut
+val ingredient = ("Sugar" , 25)
+
+println(ingredient.getClass) // class scala.Tuple2 


Not sure if we should expose beginners to .getClass here.

agree, the better way to demonstrate that something conforms to a certain type is to show that it still compiles if you add a type ascription such as (String, Int) or Tuple2[String, Int]

Jasper-M · 2018-09-14T08:55:11Z

_tour/tuples.md

+
+Tuple in Scala is a series of classes: Tuple2, Tuple3, etc., through Tuple22.
+So when we create a tuple with n elements(n lying between 2 and 22), Scala basically instantiates
+one of the corresponding class from the group, parametrized with types of constituent elements.


class -> classes
parametrized -> parameterized

Jasper-M · 2018-09-14T08:56:28Z

_tour/tuples.md

+Tuple in Scala is a series of classes: Tuple2, Tuple3, etc., through Tuple22.
+So when we create a tuple with n elements(n lying between 2 and 22), Scala basically instantiates
+one of the corresponding class from the group, parametrized with types of constituent elements.
+For eg., ingredient is of type Tuple2[String, int].


int -> Int
And I think it's better to show the (String, Int) syntax to beginners and then explain that it is syntactic sugar for Tuple2[String, Int].

Jasper-M · 2018-09-14T08:57:32Z

_tour/tuples.md

+Scala tuple also supports destructuring.
+
+```tut
+val(name, quantity) = ingredient


I prefer a space between val and (.

SethTisue · 2018-09-14T15:32:53Z

_tour/tuples.md

+
+## Iterating a tuple
+
+Tuple provides productIterator method to iterate it.


I would suggest omitting any mention of productIterator (and related methods such as productElement) from the tour entirely. They are rarely used, since they don't provide any type-safety.

SethTisue · 2018-09-14T15:34:58Z

thanks for writing this, nice work! I don't expect this will need much more work in order to become mergeable.

of the various changes suggested, I think the single most important one is Adriaan's "I'd show destructuring using patterns..."

mghildiy · 2018-09-15T16:14:50Z

This can be merged now.

martijnhoekstra · 2018-09-15T18:19:08Z

_tour/tuples.md

+}
+```
+
+() is conceptually same as Tuple0, or Unit. There can only be one value of this type since it has no elements.


This needs a bit tighter phrasing. The value () of type Unit is conceptually the same as the value () of type Tuple0 (or type sugared ()) if it existed, which it doesn't.

SethTisue · 2018-09-17T04:37:58Z

@jvican what do you make of the CI failure? I don't have rights to hit "rebuild" in Drone to see if it's transient.

jvican · 2018-09-17T16:05:51Z

Thanks I just restarted the CI

mghildiy · 2018-09-21T02:48:46Z

Please merge it.

mghildiy mentioned this pull request Sep 13, 2018

Documentation needs improvement scala/scala-lang#850

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adriaanm reviewed Sep 14, 2018

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Jasper-M suggested changes Sep 14, 2018

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SethTisue reviewed Sep 14, 2018

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martijnhoekstra reviewed Sep 15, 2018

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#850:Tuples page added to tour

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adriaanm merged commit babbc49 into scala:master Sep 21, 2018

mghildiy deleted the issue850 branch September 23, 2018 09:42


		## Iterating a tuple

		Tuple provides productIterator method to iterate it.

#850:Tuples page added to tour #1144

#850:Tuples page added to tour #1144

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mghildiy commented Sep 12, 2018

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adriaanm Sep 21, 2018 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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SethTisue commented Sep 14, 2018

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SethTisue commented Sep 17, 2018

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adriaanm Sep 21, 2018 •

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