docteurklein

<?php

$num = floatval($argv[1] ?? '1e6');
echo "iterations: $num\n";

function noop() {
}

$start = microtime(true);
printf("starting raw at:\t\t%.3F s\n", $start);

pchiusano

-- This gist shows how we can use abilities to provide nicer syntax for any monad.
-- We can view abilities as "just" providing nicer syntax for working with the
-- free monad.

ability Monadic f where
  eval : f a -> a

-- Here's a monad, encoded as a first-class value with
-- two polymorphic functions, `pure` and `bind`
type Monad f = Monad (forall a . a -> f a) (forall a b . f a -> (a -> f b) -> f b)

chrisdone

{-# LANGUAGE DataKinds #-}

-- | My database API.

module DBAPI where

import Data.Defaults

data ConnSpec p = ConnSpec
  { username :: !(Required p String)

ChrisPenner

Optics By Example Cheat Sheets

The following are appendices from Optics By Example, a comprehensive guide to optics from beginner to advanced! If you like the content below, there's plenty more where that came from; pick up the book!

• Operators
• Composition Guide
• Substitution Guide
• Optical Constarints and Types

Operator Cheat Sheet

kazu-yamamoto

{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE NumericUnderscores #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications #-}

-- |
-- To reproduce with curl, run mainTls (from ghci) and use
--
-- @

atacratic

This tutorial explains how Unison handles 'effectful' computations, like storing state or performing I/O, using abilities. It assumes you haven't come across abilities before, and covers everything from the ground up.

This is an unofficial tutorial, written before the one on unisonweb.org/docs. The approach taken here is slow and methodical. Your first stop should be the official tutorial, if you haven't seen it already.

This doc is a Unison transcript - the source is here.

Terminology note: other languages with ability systems typically call them 'effect handlers' or 'algebraic effects', but many of the ideas are the same.

Introducing abilities

clementd-fretlink

#!/usr/bin/env stack
-- stack --resolver lts-14.20 --install-ghc runghc --package either --package free
{-# LANGUAGE DeriveFunctor #-}
module Main
    where

import           Control.Applicative.Free
import           Data.Bifunctor           (first)
import           Data.Either.Combinators  (maybeToRight)
import           Data.Either.Validation

ocharles

Magic

It’s folklore that if you’re summing a list of numbers, then you should always use strict foldl. Is that really true though? foldr is useful for lists when the function we use is lazy in its second argument. For (+) :: Int -> Int -> Int this is tyically not the case, but in some sense that’s because Int is “too strict”. An alternative representation of numbers is to represent them inductively. If we do this, sumation can be lazy, and foldr can do things that foldl simply can’t!

First, let’s define natural numbers inductively, and say how to add them:

data Nat = Zero | OnePlus Nat deriving Show

one :: Nat

reinink

select
  first_name,
  last_name
from
  users
left join
  companies on companies.id = users.company_id
where (
    companies.name like 'TERM%' or
    first_name like 'TERM%' or

fabiolimace

/*
 * MIT License
 *
 * Copyright (c) 2023-2024 Fabio Lima
 * 
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is