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View functional core, imperative shell.md

1. Separation of immutable and mutable logic

Quite a lot of different people have been on the same trail of thought. Gary Bernhardt's formulation of a "functional core, imperative shell" seems to be the most voiced.

"Boundaries" - Gary Bernhardt

"Imperative shell" that wraps and uses your "functional core".. The result of this is that the shell has fewer paths, but more dependencies. The core contains no dependencies, but encapsulates the different logic paths. So we’re encapsulating dependencies on one side, and business logic on the other side. Or put another way, the way to figure out the separation is by doing as much as you can without mutation, and then encapsulating the mutation separately. Functional core — Many fast unit tests. Imperative shell — Few integration tests

https://www.youtube.com/watch?v=yTkzNHF6rMs

@andymatuschak
andymatuschak / States-v3.md
Last active Oct 7, 2019
A composable pattern for pure state machines with effects (draft v3)
View States-v3.md

A composable pattern for pure state machines with effects

State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?

There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.

Here I present a composable pattern for pure state machiness with effects,

View Makefile
# Hello, and welcome to makefile basics.
#
# You will learn why `make` is so great, and why, despite its "weird" syntax,
# it is actually a highly expressive, efficient, and powerful way to build
# programs.
#
# Once you're done here, go to
# http://www.gnu.org/software/make/manual/make.html
# to learn SOOOO much more.
@econchick
econchick / gist:4666413
Last active Oct 16, 2019
Python implementation of Dijkstra's Algorithm
View gist:4666413
class Graph:
def __init__(self):
self.nodes = set()
self.edges = defaultdict(list)
self.distances = {}
def add_node(self, value):
self.nodes.add(value)
def add_edge(self, from_node, to_node, distance):
@jakeonrails
jakeonrails / Ruby Notepad Bookmarklet
Created Jan 29, 2013
This bookmarklet gives you a code editor in your browser with a single click.
View Ruby Notepad Bookmarklet
data:text/html, <style type="text/css">#e{position:absolute;top:0;right:0;bottom:0;left:0;}</style><div id="e"></div><script src="http://d1n0x3qji82z53.cloudfront.net/src-min-noconflict/ace.js" type="text/javascript" charset="utf-8"></script><script>var e=ace.edit("e");e.setTheme("ace/theme/monokai");e.getSession().setMode("ace/mode/ruby");</script>
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