| defmodule ChangesetAssertionHelpers do | |
| alias Ecto.Changeset | |
| import ExUnit.Assertions | |
| @spec assert_changeset_error_count(Changeset.t(), non_neg_integer()) :: Changeset.t() | |
| def assert_changeset_error_count(%Changeset{} = changeset, count) do | |
| assert length(changeset.errors) == count | |
| changeset | |
| end |
| defmodule NewYearChaos do | |
| @moduledoc """ | |
| https://www.hackerrank.com/challenges/new-year-chaos/problem | |
| """ | |
| def halt_if_too_chaotic([]), do: :ok | |
| def halt_if_too_chaotic([{first, index} | rest]) do | |
| if first - index > 2, do: :halt, else: halt_if_too_chaotic(rest) | |
| end |
A compilation of my favorite functions and patterns in functional programming
Elixir is far too generous. I realize how cossetted I am when I go to use function clauses in JavaScript. Because you can't do that.
I personally detest if statements, along with case -- perhaps to a fault. Function clauses redeem me.
Why?
I hereby claim:
To claim this, I am signing this object:
A compilation of my favorite functions and patterns in functional programming
Lenses are difficult to articulate. More challenging is presenting a strong use-case. Perhaps you've already read up on lenses a bit. Perhaps your tireless search brings you here.
How does one describe a lens?
A compilation of my favorite functions and patterns in functional programming
I first learned of debounce from something of a mentor, who explained that it originates from the early days of the Internet when it was important to preclude repeated clicks to Buy Now buttons.
Generally speaking, to debounce a function is to nullify subsequent calls -- for an allotted period of time -- following the function's initial invocation. Debouncing presides as something of a governor over your function, and can be made to consolidate sequences of function calls into one.
In many contexts, its use is straightforward:
A compilation of my favorite functions and patterns in functional programming
I encountered this little gem while pair-programming with a colleague earlier this week. It affords much potential in the domain of complex sorting operations.
Say we've a large list of unsorted, unordered exam results:
def list_exam_results do
I remember when I became a developer. I had written my own implementation of Conway's Game of Life, and in doing so, had crossed a threshold. I reasoned then that programming was something I could do. I feel there are few motives so pure as coding an implementation of Life. I wonder if others do not view it as something of a rite of passage.
I find Life useful as an exercise when attempting to learn a new language or library, and accordingly, I've coded variations on my initial implementation from years ago. Most recently, I sought to use Ramda, a functional library for JavaScript. In this article, I intend to unpack the results.
Let us begin with an overview. There are two factors that characterize the specific nature of our approach:
step function, also commonly referred to as tick, evaluates as input only living cells. Here's why: there is no reason to evaluate all cells on our grid -- livin
A compilation of my favorite functions and patterns in functional programming
Haskell Curry is a giant. His first name denotes a textbook functional programming language, his last name a technique in functional programming. It's his surname that I shall address here.
While learning to program, currying to me seemed some esoteric concept in FP reserved for practitioners of Haskell and Clojure. But, in practical usage, it's remarkably simple.
As a general rule, any time I find myself calling the same function -- and passing it the same arguments -- it's a good time to curry the function. When a function is curried, we can preload it with certain arguments, and then pass it whatever its remaining arguments at will.
A compilation of my favorite functions and patterns in functional programming
The with statement may be my favorite feature of Elixir since the pipe operator. It enables the chaining of uncertainty. It affords elegance to the otherwise unsavory business of nested control structures.
There are few things in code more corrupting of beauty than:
case fetch_token() do