Match Types in Dotty

As we already know that Dotty is the new Scala version and will obviously be more stronger and powerful then Scala 2.

In Scala-2, pattern matching is only applicable to the objects and not on the types. But with the new Scala compiler i.e Dotty, it is possible to apply matching on Types also.

For example,

type Container[C] = C match {
  case String => Char
  case Array[Int] => Int
  case Iterable[Int] => Int
}

The Container is a type which gets reduce to further corresponding types as under –

Container[String] -> Char

Container[Array[Int]]-> Int, and

Container[List[Double]] -> Double

Match types are a very powerful and also provides support for recursive definition. See the example below –

import scala.compiletime.ops.int.%

type HCF[A <: Int, B <: Int] <: Int = B match {
  case 0 => A
  case _ => HCF[B, A % B]
}

Here the HCF type is of a Singleton Type. Singleton Type are the types which are instantiated with exactly one value. So you have a HCF type and then create its object as –

val hcf: HCF[10, 20] = 10

Here we have defined a value which carries the highest common factor of two numbers 10 & 20.

But if you try to change the value to something else, you should see the compilation error.

The below statement will lead to compilation error-

val hcf: HCF[10, 20] = 11

// you should see error..

val hcf: HCF[10, 20] =    11
  |                       ^^
  |                       Found:    (11 : Int)
  |                       Required: (10 : Int)

This is because value hcf is of type 10 which is a singleton type and thus exactly have one value.

Match types can also detect infinite loop if it is defined as an endless recursion. The compiler internally detects it by stack overflows. If there is a stack overflow, it will be taken as a compile-time error.

The example is available on the GitHub.

#function

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Match Types in Dotty
Myrl  Prosacco

Myrl Prosacco

1594483080

Dotty – Union Data Types

Hello folks, As we know that dotty is new Scala compiler (also know as Scala 3.0) which is coming with some new features and improvements. To get more details about the dotty and its environment setup. Please follow our beginner guide blog.

In this blog, I will describe you about newly introduced Union data type of dotty and its various properties.

A union is data type, which is denoted by “|” pipe infix operator and it looks like A | B. A union type (A | B) has a values of all values of type A and also all values of type B.

The primary reason for introducing union types in Scala is that they allow us to guarantee that for every set of types, we can always form a finite least upper bound (lub). This is both useful in practice as well as in theory. The type system of Scala 3 (i.e. dotty) is based on the DOT calculus, which has also a union data types.

A union type can also be joined with a non union types and form the finite join types. Like we can define join of a union type T1 | … | Tn as the smallest intersection type of base class instances of T1,…,Tn.

Syntactically, unions follow the same rules as intersections, but have a lower precedence than intersection(&).

Example of Dotty’s Union Types –

You can find the complete example of Dotty Union Type from here.

In this example, we have two case class models:

  • UserName
  • Password

Both have a common method lookup(). Which display the UserName and Password info on basis of its type calling.

We have also defined a getLoginInfo() method which takes a union type as an argument and return a union type value.

def getLoginInfo(loginInfo: UserName | Password): Password | UserName = {
    loginInfo match {
      case u@UserName(_) =>
        u.lookup
        u
      case p@Password(_) =>
        p.lookup
        p
    }
  }

Union types holds the commutative properties example: A | B =:= B | A

 val value1: UserName | Password = getLoginInfo(UserName("Narayan"))
  val value2: Password | UserName = getLoginInfo(UserName("Narayan"))
  if(value1 == value2) println("Commutative properties satisfy") else 
            println("Commutative properties does not satisfy")

Other Important points are –

  • Union type also supports distributive properties over the intersection (&) type.
  • Join operation on union types guarantees that the join is always finite.
  • The members of a union type are also the members of its join.
  • Union type “|” operator has lower precedence than both intersection(&) and type inference pattern (“:”) operators.
  • We can effectively use union type in pattern matching.

In next blog we will describe few more new data types of dotty. Like Type lambdas, Match types etc.

Stay Tunes, happy learning !!!

#dotty #scala #dotty #fintech #knoldus singapore #scala #singapore #singaporetech #union types

Arvel  Parker

Arvel Parker

1593156510

Basic Data Types in Python | Python Web Development For Beginners

At the end of 2019, Python is one of the fastest-growing programming languages. More than 10% of developers have opted for Python development.

In the programming world, Data types play an important role. Each Variable is stored in different data types and responsible for various functions. Python had two different objects, and They are mutable and immutable objects.

Table of Contents  hide

I Mutable objects

II Immutable objects

III Built-in data types in Python

Mutable objects

The Size and declared value and its sequence of the object can able to be modified called mutable objects.

Mutable Data Types are list, dict, set, byte array

Immutable objects

The Size and declared value and its sequence of the object can able to be modified.

Immutable data types are int, float, complex, String, tuples, bytes, and frozen sets.

id() and type() is used to know the Identity and data type of the object

a**=25+**85j

type**(a)**

output**:<class’complex’>**

b**={1:10,2:“Pinky”****}**

id**(b)**

output**:**238989244168

Built-in data types in Python

a**=str(“Hello python world”)****#str**

b**=int(18)****#int**

c**=float(20482.5)****#float**

d**=complex(5+85j)****#complex**

e**=list((“python”,“fast”,“growing”,“in”,2018))****#list**

f**=tuple((“python”,“easy”,“learning”))****#tuple**

g**=range(10)****#range**

h**=dict(name=“Vidu”,age=36)****#dict**

i**=set((“python”,“fast”,“growing”,“in”,2018))****#set**

j**=frozenset((“python”,“fast”,“growing”,“in”,2018))****#frozenset**

k**=bool(18)****#bool**

l**=bytes(8)****#bytes**

m**=bytearray(8)****#bytearray**

n**=memoryview(bytes(18))****#memoryview**

Numbers (int,Float,Complex)

Numbers are stored in numeric Types. when a number is assigned to a variable, Python creates Number objects.

#signed interger

age**=**18

print**(age)**

Output**:**18

Python supports 3 types of numeric data.

int (signed integers like 20, 2, 225, etc.)

float (float is used to store floating-point numbers like 9.8, 3.1444, 89.52, etc.)

complex (complex numbers like 8.94j, 4.0 + 7.3j, etc.)

A complex number contains an ordered pair, i.e., a + ib where a and b denote the real and imaginary parts respectively).

String

The string can be represented as the sequence of characters in the quotation marks. In python, to define strings we can use single, double, or triple quotes.

# String Handling

‘Hello Python’

#single (') Quoted String

“Hello Python”

# Double (") Quoted String

“”“Hello Python”“”

‘’‘Hello Python’‘’

# triple (‘’') (“”") Quoted String

In python, string handling is a straightforward task, and python provides various built-in functions and operators for representing strings.

The operator “+” is used to concatenate strings and “*” is used to repeat the string.

“Hello”+“python”

output**:****‘Hello python’**

"python "*****2

'Output : Python python ’

#python web development #data types in python #list of all python data types #python data types #python datatypes #python types #python variable type

vinay bajrangi

1626424144

Why We Need To Match Kundli Before Marriage?

When a date is set for marriage between two individuals, perhaps the first thing that the two families do is go for kundli matching by date of birth. Considered one of the most significant and foremost aspects of an arranged Indian marriage, matching Kundli or horoscopes is necessary before two people decide to get hitched, whether they are having a love or arranged marriage. Since matching kundlis can help you to know about any impending problems that await you on the other side of your marriage, experienced astrologers like Dr. Vinay Bajrangi always advise their clients to match horoscopes before marriage to avoid any major mishaps in the future.
Some of the reasons why astrologers recommend using a horoscope match calculator for marriage are as follows –
Compatibility - Kundli matching is important to ascertain compatibility between two individuals in terms of their mental and physical conditions, including mindset, temper, attitude and behaviour. It is considered the basic premise for a successful union. In order to assess that there is a sufficient amount of mutual desirability between the couple, the horoscopes are also analysed for physical attraction, because that is an important tool for a long-lasting relationship.
Finances/Career - Kundli matching is also a way to know about the future prospects of your spouse like career growth, business progress, promotion, financial stability, etc.
Dashas - Sometimes, the negative impact of Dashas (planetary combinations) can ruin your future as a married couple. There is a chance that a person’s horoscope could have Dashas like the ‘Mangal Dasha’ and ‘Shani Dasha’ right since the time they are born, depending upon the stars and the planets’ positions at that time. Such Dashas can create several problems at a later stage of marriage, about which none of the partners can do anything. The process of Kundli matching can help you overcome the negative impact before taking the step towards the marriage altar.
Health – Kundli matching helps you find out about the health prospects of your children, who would be born later in your life. The 8th guna of your Kundli, Nadi, represents childbirth and potential problems that might arise out of it. Therefore, Kundli matching is significant not just for yourself but also for the future generations to come.
Love Marriage – In case of love marriages, matching kundlis or using a horoscope match calculator for marriage is equally important as it helps the couple take care of any possible negative impacts awaiting them in the future. Matching of horoscopes is a sure-shot way to resolve any impending problems for a married couple.

Astrological Combinations for Healthy Marriage

The compatibility of partners as well as their health and finances are all necessary points that should be taken care of before finalizing a match. Birth charts of the two individuals provide all the answers, provided you consult a highly experienced astrologer for the same. In case of malefic effects of the planets, your married life might feel hindrance, which can be avoided with the help of some specific astrological combinations, as given below –

• Mercury and Venus are the two most significant planets in an individual’s horoscope.
• Manglik Yoga, one of the most malefic yogas, is formed in a person’s birth-chart when Mars is in the 1st, 4th, 7th, 8th or the 12th house. This yoga can be nullified only when two persons with similar yoga get married.
• Saturn and Rahu are two other planets that hold great significance in a person’s kundli with respect to his or her marriage prospects.
• When the moon is in the 2nd house of the Venus, it is considered to be highly inauspicious for the bride’s life span.
• The lifespan of both the groom and the bride is similar when the kundli shows a connection between planets Mercury and Venus.
• A groom’s life is at risk when Mercury aspects planets Sun and Rahu. Same is the case when Venus aspects planets Sun, Moon and Rahu.
• An individual whose kundli shows Jupiter aspected by Venus or Rahu aspected by Sun and Moon can expect more than one marriage in their life.

Marriage is a holy union guided by planets and houses in your birth-chart, as well as by a multitude of astrological combinations. Talk to an ace astrologer like Dr. Vinay Bajrangi to know more about kundali matching and its various aspects. What you must understand is that avoiding kundli matching before love or arranged union could keep you unaware of the vagaries of married life, if any. An individual’s nature as well as future is predicted through their kundli and it helps to seek help from a knowledgeable astrologer before making final decision about marriage. Meanwhile, if you want to have your doubts and queries addressed as per the Vedic Astrology, you can connect with Dr. Bajrangi on vinaybajrangi.com or on phone - +91 9278665588 / 9278555588.

#kundli matching by date of birth #horoscope match calculator for marriage #free kundli matching #horoscope matching for marriage #free horoscope matching by name

What a dotty build looks like?

Dotty is one of the most awaited change for scala developers. As we know its different then the Scala 2 in many ways. The major goals of this change are as follows:

  1. Making programming language compatible with the dot calculas and use lessons leart from that work.
  2. Making scala easier and safer to use. Remove wart and puzzlers.
  3. Improve consistency and expresiveness of Scala language constructs.

To know more about dotty, here is a beginers guide.

In this blog we will be setting up the local development environement to run dotty application.

While, starting working on dotty, you can start creating a sample project with dotty as I did and created a sample hello world project on my local system. Here in this blog, I am going to share the experience of creating my first dotty project and we will go throgh the findings and what problems I faced one by one with this blog.

Compling build.sbt file sucessfully**:**

I tried to create a build.sbt with most simple definition of a dotty project.

Here is the sample build.sbt file:

val dottyVersion = "0.24.0-RC1"

lazy val root = project
  .in(file("."))
  .settings(
    name := "my-dotty-sample",
    version := "0.1.0",

    scalaVersion := dottyVersion
  )

This is one of the error you might get during the compilation of project. This is because of the scala version.

To resolve this you need to update the plugins.sbt into project folder with dotty plugin as follows:

addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.4.1")

This is next error you might get, while compiling the project. This error might be there because of the sbt version. You need to use sbt version >= 1.3.6. Once you update the version if not already updated, this should be resolved.

Here is a link to download/update latest sbt version.

#dotty #scala #dotty hello world #dotty sample project #dotty with ide support

What is MATCH (MATCH) | What is MATCH token | MATCH (MATCH) ICO

What is MATCH Token?

MATCH token is a utility token for the De-Fi and Decentralized Bet (De-Bet) platforms. MATCH token is developed by a group of people who want to share the equal great opportunity to the holders through a decentralized network. MATCH token leverages the decentralized (blockchain) network because it offers more greatness compared to a centralized network. They believe as a token, it can be nurtured to become a priceless token to the holders while at the same time to be used on an application that provides secure and transparent transactions on top of a smart contract designed to get all involved persons to have the same opportunities to grow their accounts actively and passively on an ecosystem

Where MATCH token is deployed and why?

MATCH token is running on top of the TRON network which is one of the largest blockchain-based operating systems in the world. The token leverages the TRON network because it offers high-throughout, high-availability, and high-scalability. Supported by 1,332 nodes across the globe, TRON can support MATCH tokens in rendering a swift transaction time with the lowest fees compared to other smart contract networks, whereas pace is one of the nowadays application requirements. TRON TPS has exceeded the TPS of Bitcoin and Ethereum, which is one of our main reasons for selecting TRON as our main blockchain network.

Can MATCH token’s value steady and tend to be increased?

MATCH token team’s vision is to grow the token’s value by using it actively and passively in an ecosystem. Thus, the value of the token can be maintained and tend to be increased over time. This vision can be gained through De-Fi and Decentralized Bet (De-Bet) platforms.

How does the MATCH token apply De-Fi in the ecosystem?

The other proven way that can be used to grow the holders’ account passively is through a liquidity stake as part of Decentralized Finance running on top of blockchain systems to apply the Automatic Market Makers (AMM) principle. The token holders can become Liquidity Providers that could earn Swap Fee and MATCH tokens through mining based on existing APY (Annual Percentage Yield). As a Liquidity Provider, you are eligible to earn a portion of fees from the Liquidity Pool as much as 0.3% from each swap activity performed in the justswap.io platform with respect to pool shares. By staking your token in the Liquidity Pool, you can be eligible to yield a MATCH token based on the current APY. The transparent calculation is performed in the background systematically without any human interference and purely mathematical logarithm and financial investment fusion.

What is Decentralized Bet (De-Bet)?

MATCH token is a token that can only be used actively on a decentralized application (DApp) named De-Bet which is a transparent and trusted sports betting. Moreover, De-Bet is the first decentralized betting for sports in the TRON network. De-Bet focuses on User Experience and the Smart Contract technology that can help Makers and Takers to play their own roles without any human’s interference, in order to get another uplifted level of amusement in the betting arena with the benefit of Blockchain technology. De-Bet will be delivered in two phases: (1) Decentralized Betting Smart Contract and (2) Decentralized Betting for other Providers in Smart Contract. For detailed information on improvement and process flow can be found in our whitepaper (link).

How can I participate in MATCH token development?

MATCH token team will initiate ICO (Initial Currency Offering) through Private Sale and Pre-Sale events.

When is the MATCH Token Private Sale started?

The Private Sale will be opened on 6-13 Dec 2020 for limited investors. Throughout this Private Sales, we expect to gain 1,250,000 MATCH tokens with 5 TRX for each MATCH token. Be the first holder of MATCH Token! By joining this private sale you will have the opportunity to get MATCH tokens at 50% of the market price.

  • Private Sale price: 5 TRX
  • Minimum contribution: 500 TRX
  • Normal price: 10 TRXQ

Roadmap

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When is the MATCH Token Pre-Sale started?

There will be a Pre-Sale on 20 - 27 December 2020 which will be opened to the public for enthusiastic investors. From this Pre-Sale, we expect to acquire 5,000,000 MATCH tokens with 6 TRX for each MATCH token. By joining this pre-sale you will have the opportunity to get MATCH tokens at 60% of the market price.

  • Private Sale price: 6 TRX
  • Minimum contribution: 500 TRX
  • Normal price: 10 TRX

How do I get MATCH tokens during the Sale event?

It is very simple. What you need to do is have TRX in your wallet and you can just click the “Buy MATCH token" link on our site.

Can you recommend a digital wallet?

Most people are using the TRON Link wallet. Disclaimer: The MATCH team does not endorse, recommend, or make any representations with respect to digital wallets. It’s advisable to always conduct your own due diligence before trusting any third party or third-party technology.

How can I get a MATCH token after the Sale event?

You will be able to trade MATCH once MATCH listed in Justswap.io which we aim to be listed in January 2021. Disclaimer: Please note that the MATCH team does not endorse, recommend, or make any representations with respect to Internet lists or exchanges more generally. Every exchange has a different process for trading MATCH tokens and their customer support and policies and practices may vary widely. It’s advisable to conduct your own due diligence before trusting any third party or third-party technology.

Can I get an airdrop from MATCH Token?

MATCH will announce the airdrop the very first time we launch our product, and the airdrop itself will be dropped in Q1 2021. Make sure you will not miss this opportunity, follow our community channel to keep yourself updated

Instagram : https://www.instagram.com/matchtoken/

ICO DATE: Dec 6, 2020 - Dec 27, 2020

Private Sale: Dec 6 — Dec 13, 2020

Private Sale price: 5 TRX (50% Discount from the public sale price)

Pre-Sale: Dec 20 — Dec 27, 2020

Private Sale price: 6 TRX (40% Discount from the public sale price)

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