German Willkommen beim Advent of Justin 2018! Ich habe schon darüber Witze gemacht dass das passieren wird, aber jetzt ist es wohl tatsächlich soweit. Für den ersten Tag habe ich mir vorgenommen euch eines meiner schon etwas älteren Lieblingsprojekte vorzustellen: Simple-JSON. Hierbei handelt es sich um eine Library die ich ursprünglich im Juli 2017 gebaut habe, mit der Erwartung dass es nur eine

When using PureScript, one of the main features is being able to use the foreign function interface for directly calling into JavaScript to get the results you need. This has many benefits, such as Being able to give proper types to a given expression Not being limited by runtime implementations for when certain kinds of operations can be performed, especially concerning synchronous vs asynchronou

Some people who use PureScript may use Psc-Package to manage their dependencies, which works by having a package set, which is a collection of packages defined at specific versions, which can then depend on each other simply by name. At ZuriHac, I found myself in the Dhall room for a while, and thought that it might be interesting to try using it to generate my package set, and I had a working ver

前回のあらすじ Last time, I wrote "Well-typed path params in PureScript 0.12", in which I talked about how I used the Record-Format library Csongor Kiss made to then make a Symbol (type-level string) templated URL to Record parsing library that allows us to use the template to make a function of String -> Either _ { | fields }, where fields is extracted from parameters in the template: main = do let (par

Matching on JS Union members with Row Types (Handling JS Unions cont.)purescript The other day, I wrote about handling JS Unions with Row Types, by using a constructorless data type with a row parameter to note what labels I want to associate members with, with guard functions for how you would unsafely guard on these types. The unsafeGuardMember function described in that post gave us a way to el

Using IxMonad to enforce good hamburger building in Purescriptpurescript Recently, I came across a use for indexed monads to do some mutations on a foreign data type and keep track of its actual type as it changed, with a final operation for extracting out the result. While my implementation of this is hacky, there are some cool uses of IxMonad out there that provide useful restrictions, like the

Making a new library and using it in your own Psc-Package setpurescript For two years now, I've been writing PureScript-Node programs that need to spawn a child process and read the output out, and this whole time, I've been writing out the same code over and over for no real good reason. Recently, I finally decided to extract this repeated code out to a library, so I wouldn't have to maintain all

Recently, I've been wanting to make some fairly naive SQLite queries using information from record types to map what inputs should go where and what type the output should be parsed to. Well, to work with the generic information of a record type, I pull out the RowToList tricks to get to work. Select All The "simplest" of queries involves defining what record you want the results in, which means t

Even though Bower has worked and continues to work for PureScript, most end user applications benefit greatly by having a static set of dependencies installed. This post will go over the relatively simple steps it takes to upgrade an existing project using Bower to use Psc-Package instead. Why not Bower? Let's review some reasons why you might not want Bower: You probably don't need or even want t

A while ago, I talked about using row types to store validations performed on a string, but I was left feeling like the solution I came up with then wasn't quite there yet. Recently, I gave a talk about RowLists at Small FP Conf and was determined to use RowLists to improve on my previous encodings, which gave rise to Home-Run-Ball. This library allows you to specify rules to be applied to validat

Over the last couple of years, I've had a basic problem one would solve with a CRUD app -- I want to be able to easily open videos from a directory listing and then mark specific videos as watched. I first made a basic implementation for myself using Javascript and Elixir (mostly to experiment with Elixir), but found myself wanting everything that's good about Purescript that understandably doesn'