ryands · March 24, 2017 19:16
diff --git a/destructure.kt b/destructure.kt
 var (a, b) = listOf(1, 2)
diff --git a/ext.kt b/ext.kt
 fun String.reverse() : String {
  var r = ""
  forEach { r = it + r }
  return r
 }

 // usage:
 "hello world".reverse()
diff --git a/greet.kt b/greet.kt
 fun greet(name : String) : String {
  println("Hello, ${name}")
 }
diff --git a/lambda.kt b/lambda.kt
 // double each value
 listOf(1, 2, 3, 4, 5).forEach { it * 2 }

 // Only even values (use a named iterator param, rather than the default 'it')
 listOf(1, 2, 3, 4, 5).filter { v -> v % 2 == 0 }

 // You know you'll be filtering out nulls alot...
 listOf(1, 2, null, 4).filterNotNull()
diff --git a/Person.java b/Person.java
 public class Person {
  public final String name;
  public final int age;
  public final String city;

  public Person(String name, int age, String city) {
    this.name = name;
    this.age = age;
    this.city = city;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    Person person = (Person) o;

    if (age != person.age) return false;
    if (name != null ? !name.equals(person.name) : person.name != null) return false;
    return city != null ? city.equals(person.city) : person.city == null;
  }

  @Override
  public int hashCode() {
    int result = name != null ? name.hashCode() : 0;
    result = 31 * result + age;
    result = 31 * result + (city != null ? city.hashCode() : 0);
    return result;
  }

  @Override
  public String toString() {
    return "Person{" +
    "name='" + name + '\'' +
    ", age=" + age +
    ", city='" + city + '\'' +
    '}';
  }
 }
diff --git a/Person.kt b/Person.kt
 data class Person(val name: String, val age: Int, val city: String)
diff --git a/safety1.kt b/safety1.kt
 var a = 5 // fine
 var b : Int // error, needs a value
diff --git a/safety2.kt b/safety2.kt
 var a : String? = null

 println(a.length) // error
 println(a?.length) // prints "null" since a?.length is null since a is null
 println(a!!.length) // compiles, crashes with NPE
diff --git a/singlevalfunc.kt b/singlevalfunc.kt
 fun year() = 2017
diff --git a/vars.kt b/vars.kt
 var city : String = "San Francisco"
 val population : Int = 864816 // 2015 data from wikipedia
	fun String.reverse() : String {
	var r = ""
	forEach { r = it + r }
	return r
	}

	// usage:
	"hello world".reverse()
	fun greet(name : String) : String {
	println("Hello, ${name}")
	}
	// double each value
	listOf(1, 2, 3, 4, 5).forEach { it * 2 }

	// Only even values (use a named iterator param, rather than the default 'it')
	listOf(1, 2, 3, 4, 5).filter { v -> v % 2 == 0 }

	// You know you'll be filtering out nulls alot...
	listOf(1, 2, null, 4).filterNotNull()
	public class Person {
	public final String name;
	public final int age;
	public final String city;

	public Person(String name, int age, String city) {
	this.name = name;
	this.age = age;
	this.city = city;
	}

	@Override
	public boolean equals(Object o) {
	if (this == o) return true;
	if (o == null \|\| getClass() != o.getClass()) return false;

	Person person = (Person) o;

	if (age != person.age) return false;
	if (name != null ? !name.equals(person.name) : person.name != null) return false;
	return city != null ? city.equals(person.city) : person.city == null;
	}

	@Override
	public int hashCode() {
	int result = name != null ? name.hashCode() : 0;
	result = 31 * result + age;
	result = 31 * result + (city != null ? city.hashCode() : 0);
	return result;
	}

	@Override
	public String toString() {
	return "Person{" +
	"name='" + name + '\'' +
	", age=" + age +
	", city='" + city + '\'' +
	'}';
	}
	}
	var a : String? = null

	println(a.length) // error
	println(a?.length) // prints "null" since a?.length is null since a is null
	println(a!!.length) // compiles, crashes with NPE
	var city : String = "San Francisco"
	val population : Int = 864816 // 2015 data from wikipedia