| (* The syntax of our calculus. Notice that types are represented in the same way | |
| as terms, which is the essence of CoC. *) | |
| type term = | |
| | Var of string | |
| | Appl of term * term | |
| | Binder of binder * string * term * term | |
| | Star | |
| | Box | |
| and binder = Lam | Pi |
| -- in response to https://www.parsonsmatt.org/2018/11/03/trouble_with_typed_errors.html | |
| {-# LANGUAGE FlexibleContexts, FlexibleInstances, MultiParamTypeClasses #-} | |
| module CouldBe where | |
| import Control.Monad | |
| import Data.Void | |
| -- Here is an alternate, much simpler solution to the problem of keeping track of which errors have | |
| -- and haven't been handled. It doesn't use prisms nor generics, it simply uses the monad |
There exist several DI frameworks / libraries in the Scala ecosystem. But the more functional code you write the more you'll realize there's no need to use any of them.
A few of the most claimed benefits are the following:
| use std::collections::BTreeMap; | |
| use std::io::{self, Write}; | |
| pub struct Todo { | |
| name: String, | |
| checked: bool, | |
| priority: i32, | |
| } | |
| impl Todo { |
| :set prompt "> " | |
| :set -isrc | |
| :load Main |
This post also appears on lisper.in.
Reader macros are perhaps not as famous as ordinary macros. While macros are a great way to create your own DSL, reader macros provide even greater flexibility by allowing you to create entirely new syntax on top of Lisp.
Paul Graham explains them very well in [On Lisp][] (Chapter 17, Read-Macros):
The three big moments in a Lisp expression's life are read-time, compile-time, and runtime. Functions are in control at runtime. Macros give us a chance to perform transformations on programs at compile-time. ...read-macros... do their work at read-time.
