bradparker’s gists

bradparker / Lehmer.hs

Last active April 29, 2024 06:27

Lehmer.hs

	module Main where

	import Data.Array (Array, elems, listArray, (!))
	import Data.List (elemIndex, uncons, unfoldr)
	import Data.Maybe (mapMaybe)

	encodeLehmer :: forall a. (Eq a) => Array Int a -> [a] -> [Int]
	encodeLehmer set =
	unfoldr
	( fmap

bradparker / librarything-export-to-table

Last active November 6, 2024 12:13

LibraryThing JSON export to Table

	#! /usr/bin/env nix-shell
	#! nix-shell -i bash -p jq dasel

	jq \
	'[.[] \| { code: .ddc.code[0], author: .primaryauthor, title: .title }] \| sort_by(.code)' \
	< $1 \| dasel -r json -w csv

bradparker / discriminatedChunks.ts

Last active December 15, 2023 02:54

Chunk array of discriminated union by discriminant?

	const isDiscriminant = <TypeName extends string, T extends { type: TypeName }>(
	type: TypeName,
	candidate: { type: string }
	): candidate is T => type === candidate.type;

	type Chunk<
	TypeName extends string,
	T extends { type: TypeName } = any & { type: TypeName }
	> = {
	type: TypeName;

bradparker / app.ts

Last active November 14, 2023 12:11

React?

	import { useState, createElement as h, render, type Element } from "./index.js";

	const Counters = () => {
	const [count, setCount] = useState(0);

	return h(
	"div",
	{ style: "display: flex; flex-direction: column; gap: 1rem" },
	h(
	"div",

bradparker / recurrence.sql

Last active September 22, 2022 23:20

Spiking iCal recurrence rules in SQL

	-- TODO: perhaps better approach is to generate a sequence of days,
	-- weeks, months and years. Then join them.
	--
	-- TODO: I think I want the 'week of month' to work more like the
	-- 'recurrence week index', in that it could still respect "real" weeks. I
	-- think the same questions can be answered that way while being a little
	-- less surprising (that a string of 7 1s doesn't mean Mon-Sun).

	CREATE OR REPLACE FUNCTION recurrence_days (start_at timestamp, end_at timestamp, timezone text)
	RETURNS TABLE (

bradparker / relation.rb

Last active June 1, 2022 04:22

Notes from going through Time and Relational Theory by C.J. Date, Hugh Darwen and Nikos A. Lorentzos

bradparker / .gitignore

Last active April 29, 2022 05:54

Streaming server

bradparker / Combinations.hs

Created July 8, 2021 05:41

Combinations

	{-# LANGUAGE ExplicitForAll #-}

	module Combinations (combinations) where

	import Control.Arrow ((&&&))
	import Control.Monad (replicateM)
	import Control.Monad.State (StateT (StateT), evalStateT)
	import Data.List (uncons, unfoldr)

	unconses :: forall a. [a] -> [(a, [a])]

bradparker / Main.hs

Last active May 10, 2021 10:16

Learning about recursion schemes

	{-# LANGUAGE BlockArguments #-}
	{-# LANGUAGE DeriveFunctor #-}
	{-# LANGUAGE DeriveGeneric #-}
	{-# LANGUAGE InstanceSigs #-}
	{-# LANGUAGE LambdaCase #-}
	{-# LANGUAGE ScopedTypeVariables #-}
	{-# LANGUAGE TypeFamilies #-}

	module Main where

bradparker / Main.hs

Last active April 15, 2021 07:18

Some funny problem from a blog post (https://blog.ploeh.dk/2021/04/12/threading-context-through-a-catamorphism/). Excuse for recursion schemes

	{-# LANGUAGE BlockArguments #-}
	{-# OPTIONS_GHC -Wall #-}

	-- nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/bed08131cd29a85f19716d9351940bdc34834492.tar.gz -p 'haskellPackages.ghcWithPackages (p: [p.recursion-schemes])'

	module Main where

	import Control.Monad.Reader (Reader, asks, local, runReader)
	import Data.Foldable (traverse_)
	import Data.Functor.Base (TreeF (NodeF))

Brad bradparker