purely functional programming usually designates a programming paradigm—a style of building the structure and elements of computer programs—that treats all computation as the evaluation of mathematical functions.

Purely functional data structures are persistent. Persistency is required for functional programming; without it, the same computation could return different results.

Most C++ template idioms will carry over to D without alteration, but D adds some additional functionality

Whatever language or default programming paradigm a developer uses, following the monad pattern brings many of the benefits of purely functional programming.

To emphasize how Just acts on the underlying value by wrapping it, it can be redefined as a function too, called eta for now

This is done to avoid confusion by differentiating between cases where a variable carries a defined value and those where it does not.

Research beginning in the late 1980s and early 1990s established that monads could bring seemingly disparate computer-science problems under a unified, functional model.

This is a useful approach to error handling, but please don’t take it to extremes! See my post on “Against Railway-Oriented Programming”.

Modelling the flow of a program where chunks of code are executed in a certain order, with a successful “happy path” and an “error-out” path is called a Railway. It popped up in functional languages

provide interfaces so you don’t have to think about them

This is the most popular article “railway oriented programming” on one of the most popular websites of F #.

which entails computer programming (process of writing and maintaining the source code), but also encompasses a planned and structured process from the conception of the desired software to its final manifestation

One of the main reasons to work with components is re-usability and portability, but also a delegation of responsibilities. Adding a component should be as easy as simply adding the component without having to know the inner workings (or markup) of this component. A consumer should only be aware of the properties, methods and events of a component. In order to style a child component one has to be aware of the markup as well, which violates this 'delegation of responsibility'-principle.

Using a terminus to indicate a certain outcome - in turn - allows for much stronger interfaces across nested activities and less guessing! For example, in the new endpoint gem, the not_found terminus is then wired to a special “404 track” that handles the case of “model not found”. The beautiful thing here is: there is no guessing by inspecting ctx[:model] or the like - the not_found end has only one meaning!

A major improvement here is the ability to maintain more than two explicit termini. In 2.0, you had the success and the failure termini (or “ends” as we used to call them). Now, additional ends such as not_found can be leveraged to communicate a non-binary outcome of your activity or operation.

You can rescue at the method level, but more likely you’d want to rescue at the statement level.

Examples of different ways of defining forms

The central ideas of this design pattern closely mirror the semantics of first-class functions and higher-order functions in functional programming languages. Specifically, the invoker object is a higher-order function of which the command object is a first-class argument.

In programming language design, a first-class citizen (also type, object, entity, or value) in a given programming language is an entity which supports all the operations generally available to other entities. These operations typically include being passed as an argument, returned from a function, modified, and assigned to a variable.

In object-oriented programming, information hiding (by way of nesting of types) reduces software development risk by shifting the code's dependency on an uncertain implementation (design decision) onto a well-defined interface. Clients of the interface perform operations purely through it so if the implementation changes, the clients do not have to change.

Stating that some language feature or common programming idiom (like accessors) has problems is not the same thing as saying you should never use them under any circumstances.

Though getter/setter methods are commonplace in Java, they are not particularly object oriented (OO). In fact, they can damage your code's maintainability. Moreover, the presence of numerous getter and setter methods is a red flag that the program isn't necessarily well designed from an OO perspective.

Programming to interfaces is at the core of flexible structure.

The more important point comes from a program design perspective. Here, "programming to an interface" means focusing your design on what the code is doing, not how it does it. This is a vital distinction that pushes your design towards correctness and flexibility.

My understanding of "programming to an interface" is different than what the question or the other answers suggest. Which is not to say that my understanding is correct, or that the things in the other answers aren't good ideas, just that they're not what I think of when I hear that term.

Programming to an interface means that when you are presented with some programming interface (be it a class library, a set of functions, a network protocol or anything else) that you keep to using only things guaranteed by the interface. You may have knowledge about the underlying implementation (you may have written it), but you should not ever use that knowledge.

The problem with this is that it creates a strong coupling between your code and the implementation, exactly what the interface was supposed to prevent.

If the program was important enough, Microsoft might actually go ahead and add some hack to their implementation so the the program would continue to work, but the cost of that is increased complexity (with all the ensuing problems) of the Windows code. It also makes life extra-hard for the Wine people, because they try to implement the WinAPI as well, but they can only refer to the documentation for how to do this, which leads to many programs not working as they should because they (accidentally or intentionally) rely on some implementation detail.

Abstract myself from the how it does and get focus on what to do.

Say you have software to keep track of your grocery list. In the 80's, this software would work against a command line and some flat files on floppy disk. Then you got a UI. Then you maybe put the list in the database. Later on it maybe moved to the cloud or mobile phones or facebook integration. If you designed your code specifically around the implementation (floppy disks and command lines) you would be ill-prepared for changes. If you designed your code around the interface (manipulating a grocery list) then the implementation is free to change.

It's more like providing an Employee object rather than the set of linked tables you use to store an Employee record. Or providing an interface to iterate through songs, and not caring if those songs are shuffled, or on a CD, or streaming from the internet. They're just a sequence of songs.

They claim that inheritance often breaks encapsulation, given that inheritance exposes a subclass to the details of its parent's implementation.

We think that, although Ruby is a great language for the backend, the view should be written in languages designed for that purpose, HTML and JavaScript.

we get the benefit of isolating request specific logic without cramming it into a ActiveRecord model that will be used in multiple controllers/actions

A curated list of falsehoods programmers believe in.

If you have large numbers, Swift lets you use underscores as thousands separators – they don’t change the number, but they do make it easier to read.

data.frames (actually, tibbles

Unlike naming children, coding involves naming things on a daily basis. When you write code, naming things isn’t just hard, it’s a relentless demand for creativity. Fortunately, programmers are creative people.

Naming is just one part of the micro-design activity that we call programming. If design weren’t hard, we wouldn’t find good design so satisfying.

“Functional programming language” is not a clearly defined term. From the various properties that are typically associated with functional programming I only want to focus on one: “Immutability” and referential transparency.

after 4 decades, we can observe that not much has changed beside learning how to measure the “figuring out” time.

1979 in a book by Zelkowitz, Shaw, and Gannon entitled Principles of software engineering and design. It said that most of the development time was spent on maintenance (67%).

The changes we needed to make to main to reassign post mean that this implementation doesn’t quite follow the object-oriented state pattern anymore: the transformations between the states are no longer encapsulated entirely within the Post implementation. However, our gain is that invalid states are now impossible because of the type system and the type checking that happens at compile time! This ensures that certain bugs, such as display of the content of an unpublished post, will be discovered before they make it to production.

overflow-wrap: break-word; makes sure the long string will wrap and not bust out of the container. You might as well use word-wrap as well because as the spec says, they are literally just alternate names for each other. Some browsers support one and not the other.

Depending on what other component libraries you’ve used, you may be used to handling events by passing callback functions to component properties, or using a special event syntax – Svelte supports both, though one is usually more appropriate than the other depending on your situation. This post explains both ways.

You should default to the most permissive option imo and there really is no reason to check anything until you really need to If it were left to me I'd just use optional chaining, as it also eliminates the need for no-ops

ensure the relevance, accuracy and effective communication of its interpretation and education programs (see above for A.O.D.A. requirements) by: establishing clearly defined and measurable learning objectives and outcomes, and undertaking a process of program evaluation using appropriate expertise – including staff, volunteers, community groups, or consultants carrying out research ensure all staff involved in the development and delivery of interpretation and education programs, have the appropriate skills and training

have a volunteer program to encourage community participation in its activities, which should include: identification and development of volunteer opportunities procedures for recruitment of volunteers matching the needs and interests of volunteers to those of the museum provision of appropriate training and supervision for volunteers provision of a safe and secure working environment for volunteers volunteer evaluation public and private recognition of volunteers' contributions

ensure the relevance, accuracy and effective communication of each exhibit by: establishing clearly defined objectives and evaluating exhibits against their objectives using appropriate expertise, including staff, volunteers, community groups, or consultants carrying out sufficient research ensure that all staff (including volunteers) involved in the planning, preparation and installation of exhibits have the necessary skills and training

formulating written policy governing operations and defining programs securing funding necessary to carry out the museum's programs preparing or approving an annual budget and monitoring it to ensure public accountability ensuring that the purposes for which the museum exists are being fulfilled

stored instructions a program and the act of writing these instructions down and getting the instructions to be correct programming.

{ item1: "hello", item2: "world" }

pic (a drawing language)

Note: The examples in Listings 10-17, 10-18, and 10-24 declare variables without giving them an initial value, so the variable name exists in the outer scope. At first glance, this might appear to be in conflict with Rust’s having no null values. However, if we try to use a variable before giving it a value, we’ll get a compile-time error, which shows that Rust indeed does not allow null values.

To the brain, reading computer code is not the same as reading language Neuroscientists find that interpreting code activates a general-purpose brain network, but not language-processing centers.

Original objects are never modified, but transparently wrapped by observable proxies.

Proxy = observable(object) Creates and returns a proxied observable object, which behaves just like the originally passed object. The original object is not modified.

Strings generated by devalue can be safely deserialized with eval or new Function

Svelte is its own language, not plain HTML+CSS+JS

My frustration is mainly from Svelte's choices that are very un-JavaScript-like. It doesn't have to be "like React/Vue". React is React because it doesn't restrict what you can do with JavaScript for the most part. It's just common FP practice to fold/map.

Review your own code first Write a clear changelist description Automate the easy stuff Answer questions with the code itself Narrowly scope changes Separate functional and non-functional changes Break up large changelists Respond graciously to critiques Be patient when your reviewer is wrong Communicate your responses explicitly Artfully solicit missing information Award all ties to your reviewer Minimize lag between rounds of review

It was great for three things: motivation (people used what I built!)feedback (they sent me the bugs they encountered)accountability (from the moment I tweeted about this publicly, I really felt like that I’d have to finish this project… otherwise, it would be embarrassing)

Turning my Jupyter-compatible Python code into Flask-compatible Python code took dozens of hours. I ran into small bugs and errors

I had a proof-of-concept. It was great, because when you do a project, there’s always that small uncertainty that your idea is stupid and it can’t be done at all. But when you have a working prototype, all that insecurity is gone and it becomes much easier to go on.

The point is: the initial idea should be simple—because even that will turn out to be pretty complex.

The problem with hobby projects is that they don’t pay very well. At least, compared to real-life projects. But hobby projects have a lot of cool advantages that we tend to forget.

The user has a starting stack: 10,000 units of play money.In each round, she gets a deal. Something like “You have an x% probability to win y amount of money.”She can decide how much of her play money she wants to risk.And the goal is to win as much as she can in 50 rounds.

This pattern can be neater syntactically because declaring a variable in a try block with let scopes the variable to the try block.

delete myObject.regex; // or, delete myObject['regex']; // or, var prop = "regex"; delete myObject[prop];

How about renaming this to something more meaningful:

Svelte's advantage here is that it indicates the need for an update at the place where the associated data is updated, instead of at each place the data is used. Then each template expression of reactive statement is able to check very quickly if it needs to rerender or not.

can you not also use a .babelrc?

Frontend frameworks are a positive sum game! Svelte has no monopoly on the compiler paradigm either. Just like I think React is worth learning for the mental model it imparts, where UI is a (pure) function of state, I think the frontend framework-as-compiler paradigm is worth understanding. We're going to see a lot more of it because the tradeoffs are fantastic, to where it'll be a boring talking point before we know it.

This conflicts in very basic ways with what other engineering disciplines expect. Toyota's stylists might be able to sell their renderings in art galleries, but you can't drive to work in one. In software, you can.

{...{ foo: null }} was getting serialized as foo="null" because spread() was checking for strict equality with undefined. It's now checking for loose equality with null.

When you’re implementing a bad plan yourself, instead of having a mentor bail you out by fixing it, a few really useful things happen:You learn many more details about why it was a bad idea. If someone else tells you your plan is bad, they’ll probably list the top two or three reasons. By actually following through, you’ll also get to learn reasons 4–1,217.You spend about 100x more time thinking about how you’ll avoid ever making that type of mistake again, i.e., digesting what you’ve learned and integrating it into your overall decision-making.By watching my mistakes and successes play out well or badly over the course of months, I was able to build much more detailed, precise models about what does and doesn’t matter for long-term codebase health. Eventually, that let me make architectural decisions with much more conviction.

being a programmer you should always make sure that you learn by yourself and create things by yourself

Thanks for posting this helpful, well written article. Learning programming, or any other thing one takes up, requires you to sit at one place have a plan of action for your study.

The challenges are very difficult and require great thinking ability to complete. If you are a beginner then it’s gonna be really tough for you.

Project Euler

It’s powered by a large set of problems to work with, and you can also gain access to the source codes that others used to solve the given coding challenges.

Conclusions Draw your own. No? Fine. Good Enough: JSON? Protobuf Cap’n Proto Flatbuffers CBOR msgpack Avoid: YAML XML Thrift? BSON

There’s a story about an art teacher that split their class in half. They told one half of the students that they’d be graded based on a single piece of work, and the other half that they would be graded on the quantity of work produced. The half that was being graded on quantity ended up producing higher quality pieces. By iterating and learning from their mistakes they actually ended up producing better work than the students that only had to produce one piece. Quantity leads to quality. Share your work Sharing work helps you to think and develop. The feedback you get feeds into the next iteration.

All containers without a --network specified, are attached to the default bridge network. This can be a risk, as unrelated stacks/services/containers are then able to communicate.

In terms of Docker, a bridge network uses a software bridge which allows containers connected to the same bridge network to communicate, while providing isolation from containers which are not connected to that bridge network. The Docker bridge driver automatically installs rules in the host machine so that containers on different bridge networks cannot communicate directly with each other.

In practice, functional programming is all about hiding for loops, which are abstracted away by the mapper functions that automate the iteration.

Declarative programming is an enabler of abstraction. Imperative programming is an inhibitor of abstraction. Declarative programming allows you to say “I want this and I don’t care how I get it” while imperative programming requires you to define each and every step.

Your weekly reminder that1. You should not have your development process on a centralized platform, at least not if you're doing anything that smells of copyright issues2. If you do host on a centralized platform, have regular, decentralized backups of code and issue tracking.3. Also, avoid US-centric hosting for this kind of thing. But really, refer to 1.

The reason that this solves our problem is: we now have full control over the module loading order. Whatever the import order in internal.js is, will be our module loading order.

Informative data about objects that are considered prototypes for the role. Base concept is similar to type, but without inheritance of limitations and properties. Base concepts are designed as a substitute for inheritance for external concepts. A base concept is like a related concept except that the base concept is almost identical to the role definition.

Longstanding controversy surrounds the meaning of the term "hacker". In this controversy, computer programmers reclaim the term hacker, arguing that it refers simply to someone with an advanced understanding of computers and computer networks[5] and that cracker is the more appropriate term for those who break into computers, whether computer criminals (black hats) or computer security experts (white hats).

The lodash/fp module promotes a more functional programming (FP) friendly style by exporting an instance of lodash with its methods wrapped to produce immutable auto-curried iteratee-first data-last methods.

If you define a variable outside of your form, you can then set the value of that variable to the handleSubmit function that 🏁 React Final Form gives you, and then you can call that function from outside of the form.

JavaScript is, of course, a dynamic language that allows you to add and remove objects and their members at any point in time. For many, this is precisely why they enjoy the language: there are very few constraints imposed by the language.

We rarely, if ever, start with a completely blank file and start writing code. More often that not we start by copying an existing file and then modifying it to get our result.

All validators can be used independently. Inspried by functional programming paradigm, all built in validators are just functions.

FormValidation.validators.creditCard().validate({

FormValidation.formValidation(formElement

One of the primary tasks of engineers is to minimize complexity. JSX changes such a fundamental part (syntax and semantics of the language) that the complexity bubbles up to everything it touches. Pretty much every pipeline tool I've had to work with has become far more complex than necessary because of JSX. It affects AST parsers, it affects linters, it affects code coverage, it affects build systems. That tons and tons of additional code that I now need to wade through and mentally parse and ignore whenever I need to debug or want to contribute to a library that adds JSX support.

Furthermore, JSX encourages bad non-dry code. Having seen a lot of JSX over the past few months, its encourages copypasta coding.

However, as a developer that uses JSX, I find it too useful/concise to give up in the name of syntax purity, especially when I know that what it translates to is still very isolated and computationally pure.

The problem is that not all tooling supports adding new dependencies from a transform. The first step is figuring out how this can be done idiomatically in the current ecosystem.

By using HTML as the uniform interface, we can separate the interface from the engine.

interfaces

Event itself contains the properties and methods which are common to all events.

An onevent event handler property serves as a placeholder of sorts, to which a single event handler can be assigned. In order to allow multiple handlers to be installed for the same event on a given object, you can call its addEventListener() method, which manages a list of handlers for the given event on the object.

Interface specifications can be reused through inheritance but implementation need not be.

The existing interface is closed to modifications and new implementations must, at a minimum, implement that interface.

"Objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program." See also design by contract.

functional-dominant hybrid style of programming