St Louis
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8 min readIn Haskell, filtering lists is a common operation that allows you to extract elements based on a given condition. There are multiple ways to filter lists in Haskell, some of which include using list comprehensions, higher-order functions, or recursion.List comprehensions provide a concise way to filter lists by combining generators and guards. Generators define a source list, and guards specify the condition that an element must satisfy to be included in the resulting list.
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4 min readThe map function in Haskell is used to apply a given function to every element in a list, and return a new list containing the results. It has the following syntax: map :: (a -> b) -> [a] -> [b] Here, (a -> b) represents a function that takes an element of type a and returns an element of type b. [a] is the input list, and [b] is the output list.To use the map function, you need to provide it with a function and a list.
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5 min readTo publish Microweber on OVHcloud, you can follow these steps:Sign up for an account on OVHcloud and purchase a suitable hosting plan.Access your OVHcloud account and navigate to the control panel.Create a new database for Microweber by selecting the appropriate option in the database section.Install an FTP client, such as FileZilla, and connect it to your OVHcloud server using the provided credentials.Download the Microweber CMS package from the official website.
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7 min readTo perform file operations in Haskell, you can use the System.IO module, which is part of the Haskell standard library. This module provides functions for opening, reading, writing, and closing files.To start, you need to import the System.IO module: import System.IO To open a file, you can use the openFile function. It takes the file path and the mode in which the file should be opened.
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7 min readLazy evaluation is a key feature of Haskell programming language that allows the evaluation of expressions to be delayed until their values are actually needed. This can lead to more efficient and concise code, as it avoids unnecessary computations.In Haskell, lazy evaluation is achieved by representing computations as expressions, which are only evaluated when their value is required by another expression.
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5 min readTo run Prometheus on AWS, you need to follow these steps:Launch an EC2 instance: Start by creating an AWS EC2 instance, which will act as the Prometheus server. Make sure you choose an instance type and size that suits your needs. Configure security groups: Configure the security groups associated with your EC2 instance to allow incoming traffic on the Prometheus port (default is 9090) from your desired sources (e.g., specific IP addresses or ranges).
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5 min readThe "where" clause is a useful feature in Haskell that allows you to define local helper functions or values within a function. It helps in improving code readability and reusing common computations.To use the "where" clause, you need to follow these steps:Start by defining your main function or expression.After the main function or expression, add the "where" keyword followed by a block of definitions.
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6 min readIn Haskell, type classes are a powerful feature that allow you to define and use polymorphic functions based on the behavior of specific types. Type classes provide a way to group types that support a common set of operations, such as arithmetic or comparison.To define a type class, you specify a set of functions or operations that the type must support. This is done using the class keyword, followed by the name of the type class and a list of function signatures.
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8 min readMicroweber is a user-friendly and intuitive website builder and content management system (CMS) that allows you to create and manage websites without any technical knowledge. It supports various deployment options, giving you flexibility to choose a hosting solution that best fits your needs.You can deploy Microweber on various platforms, including:Shared Hosting: Microweber can be installed on shared hosting environments offered by popular hosting providers.
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6 min readThe "do" notation in Haskell is a syntactic sugar that allows you to write imperative-style code in a more concise and readable way. It is primarily used when working with monads, which are a way of structuring computations that involve side effects.To use the "do" notation, you first need to understand the concept of monads in Haskell.
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5 min readTo use the pg_cron extension for scheduled tasks in PostgreSQL, you need to follow these steps:Install the pg_cron extension: Download the extension from the PostgreSQL website or use a package manager to install it. On Linux, you can run make && sudo make install within the extension's source code directory. Enable the extension: In your PostgreSQL database, connect as a superuser or use a user with the CREATETEXT privilege.