OVERVIEW
Haskell is a Functional Programming Language that has been specially designed to handle symbolic computation and list-processing applications. Functional programming is based on mathematical functions. Besides Haskell
In conventional programming, instructions are taken as a set of declarations in a specific syntax or format, but in the case of functional programming, all the computation is considered as a combination of separate mathematical functions.
Going Functional with Haskell
Haskell is a widely used purely functional language. Here, we have listed down a few points that make this language so special over other conventional programming languages such as Java, C, C++, PHP, etc.
Functional Language − In conventional programing language, we instruct the compiler on a series of tasks which is nothing but telling your computer "what to do" and "how to do?" But in Haskell, we will tell our computer "What it is?"
Laziness − Haskell is a lazy language. By lazy, we mean that Haskell won't evaluate any expression without any reason. When the evaluation engine finds that an expression needs to be evaluated, then it creates a thunk data structure to collect all the required information for that specific evaluation and a pointer to that thunk data structure. The evaluation engine will start working only when it is required to evaluate that specific expression.
Modularity − A Haskell application is nothing but a series of functions. We can say that a Haskell application is a collection of numerous small Haskell applications.
Statically Typed − In conventional programing language, we need to define a series of variables along with their type. In contrast, Haskell is a type of interference language. By the term, type interference language, we mean the Haskell compiler is intelligent enough to figure out the type of the variable declared, hence we need not explicitly mention the type of the variable used.
Maintainability − Haskell applications are modular and hence, it is very easy and cost-effective to maintain them.
GET STARTED
To choose a Region follow the below step:
1. Sign in to the AWS Management Console.
2. Choose a service to go to that service's console.
3. In the navigation bar, choose the name of the currently displayed Region. Then choose the Region to which you want
to switch.
Step instructions for how to assess and monitor the health and proper function of the application:
1. Navigate to your Amazon EC2 console and verify that you're in the correct region.
2. Choose Instance and select your launched instance.
3. Select the server to display your metadata page and choose the Status checks tab at the bottom of the page to review if your status checks passed or failed.
To verify the installation, follow the below instructions
Step 1. Connect to SSH:
Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.
In the navigation pane, choose Instances.
Select the instance and choose Connect.
Choose SSH Client
Copy the SSH command and paste it into the terminal.
ssh admin@publicIP -i [Path of key pair file]If it shows an access denied message run the following command, then run the above command again to connect via ssh.
chmod 400 [Path of key pair file]Once launched in the Amazon EC2 Service, please connect to the instance via an SSH client using the ec2-user with the key pair associated at launch. Once connected as the ec2-user user, you will be able to sudo to the root user
Step 2. Verify the installation
Follow the steps to verify the Haskell Language installation
1. Login with ssh
2. Type the below command to check the version
3. To check the version :
ghci --version
How to use Haskell Language in the terminal:
1. After connecting with ssh write the below command:
sudo vi hello.hs3. Paste the following code into the file: :
main :: IO ()
main = putStrLn "Hello, world!" 2. After that use the below command :
ghc -o hello hello.hs4. Then run the below command :
./helloThe output "Hello, World" should appear in your terminal.
That's it! You have successfully printed "Hello, World!" using Haskell Language in the terminal.
4. After using the above command then verify written the below command mentioned below image:
To monitor and assess application functions:-
a. Navigate to your Amazon EC2 console and verify that you're in the correct region.
b. Choose Instances and select your launched instance.
c. Select the server to display your metadata page and choose the Status checks tab at the bottom of the page to review if your status checks passed or failed.
For detailed information on how to use this application please visit: https://www.tutorialspoint.com/haskell/index.htm
For detailed information about managing and requesting increased service please visit: https://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html
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