We've been writing Ruby for years on lots of different projects and in many different environments. This has led to thoughtbot's Ruby style to be somewhat different to the rest of the community's. In particular, we tend to focus on a sub-set of Ruby's features. Derek and Joël some of those differences and the reasoning behind them.
Style guide: https://github.com/thoughtbot/guides
| -- 0.19 | |
| randomToTask : Generator a -> Task x a | |
| randomToTask generator = | |
| Time.now | |
| |> Task.map (Tuple.first << Random.step generator << Random.initialSeed << Time.posixToMillis) | |
| -- 0.18 |
| delay : Time -> a -> Cmd a | |
| delay t x = | |
| Task.perform (always x) <| Process.sleep t | |
| cmd : msg -> Cmd msg | |
| cmd msg = | |
| Task.perform (always msg) (Task.succeed msg) | |
| initSeed = 100 |
Compilers are powerful helpers but they can only do so much with primitives. Joël and Stephanie fix a bug by introducing domain-specific types. Learn about how these encode real-world context, what are the downsides, and how some functional programming concepts can make those downsides go away.
Previously discussed, don't depend too heavily on low-level constructs.
Our languages give us great tools in the form of primitives: things like integers, strings, and arrays. However, over-relying on these leads to problems. This practice even has it's own fancy code smell name: Primitive Obssession. In this video, Derek and Joël take a look at Primitive Obsession and the various abstraction tools languages provide to deal with it.
Over relying on hashes/arrays
Representing dollars/cents as an two-element array:
Script to generate domain-specific Elm types wrapping primitives (see https://robots.thoughtbot.com/lessons-learned-avoiding-primitives-in-elm for why this is a good idea)
Use looks like:
% ./create_newtype Email String > email.elm
module Email exposing (Email, fromString, toString, map, map2)
Provide a concise description for the program limited to 600 characters or less.
From the earliest cave paintings to today's GPS-assisted smartphone apps, maps have been an important part of we have described the world around us. But what goes into turning the life-size 3d world into a 2d image that fits in your