mstksg

# Haskell stack project Github Actions template
# https://gist.github.com/mstksg/11f753d891cee5980326a8ea8c865233
#
# To use, mainly change the list in 'plans' and modify 'include' for
# any OS package manager deps.
#
# Currently not working for cabal-install >= 3
#
# Based on https://raw.githubusercontent.com/commercialhaskell/stack/stable/doc/travis-complex.yml
#

copumpkin

{-# LANGUAGE GADTs, RankNTypes, TypeFamilies, DataKinds, PolyKinds, TypeOperators, ScopedTypeVariables #-}

-- Lots of ways you can phrase this, but this works for me
-- For folks who haven't seen it before, this is "the essence of the sum type" and sigma stands for sum.
-- You see it far more often in dependent types than elsewhere because it becomes a lot more pleasant to
-- work with there, but it's doable in other contexts too. Think of the first parameter to the data
-- constructor as a generalized "tag" as we talk about in "tagged union", and the second parameter is the
-- "payload". It turns out that you can represent any simple sum type you could write in Haskell this way
-- by using a finite and enumerable `f`, but things can get more unusual when `f` isn't either. In such
-- cases, it's often easier to think of this as the essence of existential types.

kuviman

Web renderer for Russian AI Cup

Russian AI Cup — open artificial intelligence programming contest where you can test yourself writing a game strategy! It’s simple, clear and fun! We welcome both novice programmers — students and pupils, as well as professionals. Writing your own strategy is very simple: basic programming skills are enough.

This competition was being held for the sixth time, and this time we made a game of the RTS game genre — players were controlling 500 vehicles of 5 different types at once. The task is to destroy the opponent!

My part was to implement the web renderer — the one you see on the site. There is also a technical renderer with schematic graphics used by participants for local testing.

passy

I had a fun refactoring example in Haskell today I wanted to share. So, I've got a structure with a nested Maybe inside, which looked like this:

Maybe (Vector.Vector (Maybe (Direction, [Departure])))

I wanted to get that second-level Maybe folded into the first as it didn't provide any semantic meaning. So I start by writing the type definition:

proger

{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE StandaloneDeriving #-}

module Realm.Newrelic where

import Control.Monad.Trans.Either

import Data.Proxy

dbp

dependencies:
  cache_directories:
    - "~/.stack"
  pre:
    - wget https://github.com/commercialhaskell/stack/releases/download/v0.1.2.0/stack-0.1.2.0-x86_64-linux.gz -O /tmp/stack.gz
    - gunzip /tmp/stack.gz && chmod +x /tmp/stack
    - sudo mv /tmp/stack /usr/bin/stack
  override:
    - stack setup
    - stack build

travisbhartwell

NOTE: a more up-to-date version of this can be found on my blog

nix-shell and Shebang Lines

A few days ago, version 1.9 of the Nix package manager was released. From the release notes:

nix-shell can now be used as a #!-interpreter. This allows you to write scripts that dynamically fetch their own dependencies.

andrejbauer

Fuuzetsu

#!/usr/bin/env bash
cabal configure && cabal build && cabal haddock --hyperlink-source \
                                    --html-location='/package/$pkg-$version/docs' \
                                    --contents-location='/package/$pkg'
S=$?
if [ "${S}" -eq "0" ]; then
    cd "dist/doc/html"
    DDIR="${1}-${2}-docs"
    cp -r "${1}" "${DDIR}" && tar -c -v -z --format=ustar -f "${DDIR}.tar.gz" "${DDIR}"
    CS=$?

egid

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