Sedose’s gists

Sedose / Delegate all members.scala

Last active September 14, 2024 09:14

Delegation pattern using Scala. Zero boilerplate code. Delegate all members | Delegate some of members

	trait DatabaseOperations:
	def createDatabase(): Unit
	def manageDatabase(): Unit
	def maintainDatabase(): Unit

	class CloudProvider extends DatabaseOperations:
	def createDatabase(): Unit =
	println("Cloud Provider creates the database.")
	def manageDatabase(): Unit =
	println("Cloud Provider manages the database.")

Sedose / MacroDef.scala

Last active September 10, 2024 10:26

Counting Matching Non-Null Fields with Macro. Reduce code duplication

	import scala.quoted.{quotes, Expr, Quotes, Type}

	inline def compareEntity[T](a: T, b: T): Int =
	${compareEntitiesImpl('a, 'b)}

	def compareEntitiesImpl[T: Type](a: Expr[T], b: Expr[T])(using Quotes): Expr[Int] = {
	import quotes.reflect.*

	val tpe = TypeRepr.of[T]
	val fields = tpe.typeSymbol.caseFields

Sedose / AAA. MacroDef.scala

Last active September 10, 2024 12:32

ChatGPT generated. Working. Scala macro for entities custom comparison logic + Analogs without Macro

	import scala.quoted.*

	inline def compareEntity[T](a: T, b: T): Boolean =
	${compareEntitiesImpl('a, 'b)}

	def compareEntitiesImpl[T: Type](a: Expr[T], b: Expr[T])(using Quotes): Expr[Boolean] = {
	import quotes.reflect.*

	val tpe = TypeRepr.of[T]
	val fields = tpe.typeSymbol.caseFields

Sedose / Main.scala

Created September 7, 2024 08:10

Scala solution for https://leetcode.com/problems/ugly-number/description/

	@main def main(): Unit =
	println(isUgly(14))

	private val primes = List(2, 3, 5)

	def isUgly(n: Int): Boolean =
	var result = n
	for (prime <- primes)
	while (result > 1 && result % prime == 0)
	result /= prime

Sedose / Main.scala

Created September 6, 2024 09:12

Scala's implicit singleton dependency injection is implemented in the language itself, rather than implicitly in a framework like in Java, or done explicitly.

	// Define a trait for a generic Database Access Object
	trait UserDao {
	def getUser(id: Int): String
	}

	// Concrete implementation of UserDao
	class UserDaoImpl extends UserDao {
	def getUser(id: Int): String = s"User with ID $id"
	}

Sedose / Main.scala

Created September 6, 2024 09:03

Scala 3 implicit function parameter

	@main def main(): Unit =
	// Implicit parameter declaration
	implicit val defaultMultiplier: Int = 2

	// Function taking implicit parameter
	def multiplyBy(x: Int)(implicit multiplier: Int): Int = x * multiplier

	// Function call without explicitly passed parameter
	val result = multiplyBy(10) // compiler injects defaultMultiplier automatically

Sedose / Main.scala

Created September 5, 2024 23:20

Union types. Exhaustive `match` (`switch` Java analog, `when` Kotlin analog). Without Java wrappers shit

	@main def main(): Unit =
	val value1 = true
	val value2 = 1234L
	val value3 = "Hello Scala 3!"
	println(process(value1)) // "Received a Boolean: true"
	println(process(value2)) // "Received a Long: 123"
	println(process(value3)) // "Hello Scala 3!"

	type ExternalType1 = java.lang.Boolean
	type ExternalType2 = java.lang.Long

Sedose / Main.java

Last active September 4, 2024 13:29

Java record instances are equal by the record members

	import java.util.Objects;

	private record AddressIdentity(
	String city,
	String streetName,
	String streetNumber
	) {}

	void main() {
	var first = new AddressIdentity("Kyiv", "Babusia", "12345");

Sedose / Single queue using 2 stacks.java

Last active September 3, 2024 19:54

Leetcode Single queue using 2 stacks.java. Using Java implicitly named classes. Just to show that we can do Java without explicitly named classes

	import java.util.ArrayList;
	import java.util.List;

	void main() {
	System.out.println("Hello, Java 22!");

	QueueOperations queue = createQueue(createStack(), createStack());

	queue.push(1);
	queue.push(2);

Sedose / Single queue using 2 stacks.kt

Last active September 3, 2024 06:35

Single queue using 2 stacks impl for Leetcode problem

	package org.example

	fun main() {
	createQueue(createStack(), createStack()).apply {
	push(1)
	push(2)
	push(3)
	pop()
	peek()
	pop()

Edgar Sedose