From 496b11f8ce33f38fc1e29c23ee8c4261a811b967 Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:47:02 +0700 Subject: scala: consistent style, language correction --- scala.html.markdown | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index e6638121..12441af9 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -16,15 +16,16 @@ Scala - the scalable language Set yourself up: 1) Download Scala - http://www.scala-lang.org/downloads - 2) unzip/untar in your favourite location and put the bin subdir on the path - 3) Start a scala REPL by typing scala. You should see the prompt: + 2) Unzip/untar to your favourite location and put the bin subdir in your `PATH` environment variable + 3) Start a Scala REPL by running `scala`. You should see the prompt: scala> - This is the so called REPL (Read-Eval-Print Loop). You may type any valid - Scala expression into it, and the result will be printed. We will explain what - Scala files look like further into this tutorial, but for now, let's start - with some basics. + This is the so called REPL (Read-Eval-Print Loop). You may type any Scala + expression, and the result will be printed. We will explain what Scala files + look like further into this tutorial, but for now, let's start with some + basics. + */ -- cgit v1.2.3 From 9ddf69a14da14c0d29abb5a18b4d2dfd5a39c7b2 Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:48:28 +0700 Subject: scala: language correction --- scala.html.markdown | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 12441af9..4121dc9b 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -5,6 +5,7 @@ contributors: - ["George Petrov", "http://github.com/petrovg"] - ["Dominic Bou-Samra", "http://dbousamra.github.com"] - ["Geoff Liu", "http://geoffliu.me"] + - ["Ha-Duong Nguyen", "http://reference-error.org"] filename: learn.scala --- @@ -33,10 +34,10 @@ Scala - the scalable language // 1. Basics ///////////////////////////////////////////////// -// Single line comments start with two forward slashes +// Single-line comments start with two forward slashes /* - Multi line comments, as you can already see from above, look like this. + Multi-line comments, as you can already see from above, look like this. */ // Printing, and forcing a new line on the next print -- cgit v1.2.3 From 8c06438ec9aec991b78bbd49d2343dc820da7669 Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:49:15 +0700 Subject: scala: correct format --- scala.html.markdown | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 4121dc9b..03d80043 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -48,7 +48,7 @@ println(10) print("Hello world") // Declaring values is done using either var or val. -// val declarations are immutable, whereas var's are mutable. Immutability is +// val declarations are immutable, whereas vars are mutable. Immutability is // a good thing. val x = 10 // x is now 10 x = 20 // error: reassignment to val -- cgit v1.2.3 From 5b683b34ddb313b8981f360c4a6b54cfbc3af396 Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:49:54 +0700 Subject: scala: easier-to-look comment --- scala.html.markdown | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 03d80043..0bd1a56d 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -51,9 +51,9 @@ print("Hello world") // val declarations are immutable, whereas vars are mutable. Immutability is // a good thing. val x = 10 // x is now 10 -x = 20 // error: reassignment to val +x = 20 // error: reassignment to val var y = 10 -y = 20 // y is now 20 +y = 20 // y is now 20 /* Scala is a statically typed language, yet note that in the above declarations, @@ -73,17 +73,17 @@ true false // Boolean operations -!true // false -!false // true +!true // false +!false // true true == false // false -10 > 5 // true +10 > 5 // true // Math is as per usual -1 + 1 // 2 -2 - 1 // 1 -5 * 3 // 15 -6 / 2 // 3 -6 / 4 // 1 +1 + 1 // 2 +2 - 1 // 1 +5 * 3 // 15 +6 / 2 // 3 +6 / 4 // 1 6.0 / 4 // 1.5 -- cgit v1.2.3 From dbdde5134b4c5777467a81c8fdf2128cb44edacc Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:50:32 +0700 Subject: scala: clearer comments --- scala.html.markdown | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 0bd1a56d..8d93169b 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -122,12 +122,12 @@ s"We have $n apples" // => "We have 45 apples" // Expressions inside interpolated strings are also possible val a = Array(11, 9, 6) -s"My second daughter is ${a(0) - a(2)} years old." // => "My second daughter is 5 years old." +s"My second daughter is ${a(0) - a(2)} years old." // => "My second daughter is 5 years old." s"We have double the amount of ${n / 2.0} in apples." // => "We have double the amount of 22.5 in apples." -s"Power of 2: ${math.pow(2, 2)}" // => "Power of 2: 4" +s"Power of 2: ${math.pow(2, 2)}" // => "Power of 2: 4" // Formatting with interpolated strings with the prefix "f" -f"Power of 5: ${math.pow(5, 2)}%1.0f" // "Power of 5: 25" +f"Power of 5: ${math.pow(5, 2)}%1.0f" // "Power of 5: 25" f"Square root of 122: ${math.sqrt(122)}%1.4f" // "Square root of 122: 11.0454" // Raw strings, ignoring special characters. -- cgit v1.2.3 From efb338608b3b6e5af3652e71aa7fb85bdf5917b9 Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:55:38 +0700 Subject: scala: consistent code format --- scala.html.markdown | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 8d93169b..62af31b6 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -173,8 +173,8 @@ def sq(x: Int) = x * x // Compiler can guess return type is Int // Functions can have default parameters: def addWithDefault(x: Int, y: Int = 5) = x + y -addWithDefault(1, 2) // => 3 -addWithDefault(1) // => 6 +addWithDefault(1, 2) // => 3 +addWithDefault(1) // => 6 // Anonymous functions look like this: @@ -195,8 +195,8 @@ sq(10) // => 100 val addOne: Int => Int = _ + 1 val weirdSum: (Int, Int) => Int = (_ * 2 + _ * 3) -addOne(5) // => 6 -weirdSum(2, 4) // => 16 +addOne(5) // => 6 +weirdSum(2, 4) // => 16 // The return keyword exists in Scala, but it only returns from the inner-most @@ -206,9 +206,9 @@ weirdSum(2, 4) // => 16 def foo(x: Int): Int = { val anonFunc: Int => Int = { z => if (z > 5) - return z // This line makes z the return value of foo! + return z // This line makes z the return value of foo! else - z + 2 // This line is the return value of anonFunc + z + 2 // This line is the return value of anonFunc } anonFunc(x) // This line is the return value of foo } @@ -361,7 +361,7 @@ class Dog(br: String) { val mydog = new Dog("greyhound") println(mydog.breed) // => "greyhound" -println(mydog.bark) // => "Woof, woof!" +println(mydog.bark) // => "Woof, woof!" // The "object" keyword creates a type AND a singleton instance of it. It is @@ -543,8 +543,8 @@ implicit def myImplicitFunction(breed: String) = new Dog("Golden " + breed) // By itself, implicit keyword doesn't change the behavior of the value, so // above values can be used as usual. -myImplicitInt + 2 // => 102 -myImplicitFunction("Pitbull").breed // => "Golden Pitbull" +myImplicitInt + 2 // => 102 +myImplicitFunction("Pitbull").breed // => "Golden Pitbull" // The difference is that these values are now eligible to be used when another // piece of code "needs" an implicit value. One such situation is implicit @@ -572,8 +572,8 @@ def foo[T : C] = ... // implicit conversion of type A => B, where A is the type of obj, and B has a // method called "method", that conversion is applied. So having // myImplicitFunction above in scope, we can say: -"Retriever".breed // => "Golden Retriever" -"Sheperd".bark // => "Woof, woof!" +"Retriever".breed // => "Golden Retriever" +"Sheperd".bark // => "Woof, woof!" // Here the String is first converted to Dog using our function above, and then // the appropriate method is called. This is an extremely powerful feature, but -- cgit v1.2.3 From 7c02089687eaee9c1fe9b1db3ab0674153077f56 Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:55:59 +0700 Subject: scala: consistent code format --- scala.html.markdown | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 62af31b6..35042ebe 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -220,19 +220,19 @@ def foo(x: Int): Int = { 1 to 5 val r = 1 to 5 -r.foreach( println ) +r.foreach(println) r foreach println // NB: Scala is quite lenient when it comes to dots and brackets - study the // rules separately. This helps write DSLs and APIs that read like English -(5 to 1 by -1) foreach ( println ) +(5 to 1 by -1) foreach (println) // A while loops var i = 0 -while (i < 10) { println("i " + i); i+=1 } +while (i < 10) { println("i " + i); i += 1 } -while (i < 10) { println("i " + i); i+=1 } // Yes, again. What happened? Why? +while (i < 10) { println("i " + i); i += 1 } // Yes, again. What happened? Why? i // Show the value of i. Note that while is a loop in the classical sense - // it executes sequentially while changing the loop variable. while is very @@ -241,19 +241,19 @@ i // Show the value of i. Note that while is a loop in the classical sense - // A do while loop do { - println("x is still less than 10"); + println("x is still less than 10") x += 1 } while (x < 10) // Tail recursion is an idiomatic way of doing recurring things in Scala. // Recursive functions need an explicit return type, the compiler can't infer it. // Here it's Unit. -def showNumbersInRange(a:Int, b:Int):Unit = { +def showNumbersInRange(a:Int, b:Int): Unit = { print(a) if (a < b) showNumbersInRange(a + 1, b) } -showNumbersInRange(1,14) +showNumbersInRange(1, 14) // Conditionals @@ -307,13 +307,13 @@ s(1) (a, 2, "three") // Why have this? -val divideInts = (x:Int, y:Int) => (x / y, x % y) +val divideInts = (x: Int, y: Int) => (x / y, x % y) -divideInts(10,3) // The function divideInts gives you the result and the remainder +divideInts(10, 3) // The function divideInts gives you the result and the remainder // To access the elements of a tuple, use _._n where n is the 1-based index of // the element -val d = divideInts(10,3) +val d = divideInts(10, 3) d._1 @@ -416,8 +416,8 @@ val otherGeorge = george.copy(phoneNumber = "9876") def matchPerson(person: Person): String = person match { // Then you specify the patterns: case Person("George", number) => "We found George! His number is " + number - case Person("Kate", number) => "We found Kate! Her number is " + number - case Person(name, number) => "We matched someone : " + name + ", phone : " + number + case Person("Kate", number) => "We found Kate! Her number is " + number + case Person(name, number) => "We matched someone : " + name + ", phone : " + number } val email = "(.*)@(.*)".r // Define a regex for the next example. @@ -448,7 +448,7 @@ def matchEverything(obj: Any): String = obj match { case List(1, b, c) => s"Got a list with three elements and starts with 1: 1, $b, $c" // You can nest patterns: - case List(List((1, 2,"YAY"))) => "Got a list of list of tuple" + case List(List((1, 2, "YAY"))) => "Got a list of list of tuple" } // In fact, you can pattern match any object with an "unapply" method. This @@ -495,7 +495,7 @@ sSquared.reduce (_+_) // The filter function takes a predicate (a function from A -> Boolean) and // selects all elements which satisfy the predicate List(1, 2, 3) filter (_ > 2) // List(3) -case class Person(name:String, age:Int) +case class Person(name: String, age: Int) List( Person(name = "Dom", age = 23), Person(name = "Bob", age = 30) @@ -596,7 +596,7 @@ import scala.collection.immutable._ import scala.collection.immutable.{List, Map} // Rename an import using '=>' -import scala.collection.immutable.{ List => ImmutableList } +import scala.collection.immutable.{List => ImmutableList} // Import all classes, except some. The following excludes Map and Set: import scala.collection.immutable.{Map => _, Set => _, _} -- cgit v1.2.3 From 513235c4754f87e64e5d564bb53ec643ce9333df Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:56:11 +0700 Subject: scala: clearer further resources (itemized) --- scala.html.markdown | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 35042ebe..10db5f78 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -631,13 +631,8 @@ writer.close() ## Further resources -[Scala for the impatient](http://horstmann.com/scala/) - -[Twitter Scala school](http://twitter.github.io/scala_school/) - -[The scala documentation](http://docs.scala-lang.org/) - -[Try Scala in your browser](http://scalatutorials.com/tour/) - -Join the [Scala user group](https://groups.google.com/forum/#!forum/scala-user) - +* [Scala for the impatient](http://horstmann.com/scala/) +* [Twitter Scala school](http://twitter.github.io/scala_school/) +* [The scala documentation](http://docs.scala-lang.org/) +* [Try Scala in your browser](http://scalatutorials.com/tour/) +* Join the [Scala user group](https://groups.google.com/forum/#!forum/scala-user) -- cgit v1.2.3 From d61ad107759c99de3dd32dc848086c16dbb14f15 Mon Sep 17 00:00:00 2001 From: "Ha-Duong, NGUYEN" Date: Mon, 3 Aug 2015 15:58:36 +0700 Subject: scala: consistent code format --- scala.html.markdown | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'scala.html.markdown') diff --git a/scala.html.markdown b/scala.html.markdown index 10db5f78..c482752d 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -178,7 +178,7 @@ addWithDefault(1) // => 6 // Anonymous functions look like this: -(x:Int) => x * x +(x: Int) => x * x // Unlike defs, even the input type of anonymous functions can be omitted if the // context makes it clear. Notice the type "Int => Int" which means a function @@ -248,7 +248,7 @@ do { // Tail recursion is an idiomatic way of doing recurring things in Scala. // Recursive functions need an explicit return type, the compiler can't infer it. // Here it's Unit. -def showNumbersInRange(a:Int, b:Int): Unit = { +def showNumbersInRange(a: Int, b: Int): Unit = { print(a) if (a < b) showNumbersInRange(a + 1, b) -- cgit v1.2.3