klapaucius

Строгость и нищета списков.

Map и структурная рекурсия.

Применить функцию к каждому элементу списка - это просто:

GHC/Base.lhs

map _ []     = []
map f (x:xs) = f x : map f xs

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

matklad

# Put this file into `~/.config/nixpkgs/overlays/idea.nix`.
# Then, install IDEA with `nix-env -iA nixos.idea-community`.

self: super:

{
  jbsdk = super.callPackage ~/config/nix/jbsdk.nix {}; # you might need to override this path.

  idea-community = let 
    version = "2017.2.3";

taktoa

I started writing this polemic to answer your question, but I ended up touching on most of my gripes with Haskell in general, not just in a corporate context.

GHC

GHC is a modern compiler with an amazing RTS and tons of features, but I have some issues with it.

Monolithic and Hard to Contribute To

cblp

-- stack --resolver=lts-10.5 script

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE Rank2Types #-}

module Write where

import           Codec.Xlsx
import           Control.Lens
import           Control.Monad.State.Strict

corpix

Requirements:

• root directory is a git repository(for git rev-parse --show-toplevel)
• github.com/nixos/nixpkgs at pkgs/nixpkgs

Tree:

.
├── .git

parsonsmatt

Someone asked whether or not acid-state was production ready. I shared my experiences:

parsonsmatt [11:32 AM] @nikolap it's used by cardano-wallet and Hackage. Based on my experience with acid-state, I'd say it is not a good choice for production data storage. For local desktop apps, SQLite is a much better choice, and for real production apps, Postgresql is king.

parsonsmatt [11:44 AM] acid-state did not have a test suite, at all, until I implemented the very first tests (for TemplateHaskell code generation) earlier this year. It has picked up some tests since then, but I'm still not confident in it's correctness.

It claims to be resilient to unplugging the power cord, but I doubt that, as it's not resilient to Ctrl-C: acid-state/acid-state#79

chrisdone

{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE ParallelListComp #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE DisambiguateRecordFields #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}