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Semantic Commit Messages

See how a minor change to your commit message style can make you a better programmer.

Format: <type>(<scope>): <subject>

<scope> is optional

Example

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%% @doc A binary tree implementation in Erlang.
%%      A binary tree stores keys and values.

-module(binary_tree).
-export([init/0, init/1, insert/3, lookup/2]).
-define(EMPTY_NODE, {node, 'empty'}).

%% @doc Initialize an empty binary tree node.
%%      This is how the root of the tree should be established.
%%

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-module(rbtree).
-export([insert/3, find/2]).

% Node structure: { Key, Value, Color, Smaller, Bigger }

find(_, nil) ->
  not_found;

find(Key, { Key, Value, _, _, _ }) ->
  { found, { Key, Value } };

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  defmodule EmailValidator do
  
    # ensure that the email looks valid
    def validate_email(email) when is_binary(email) do
      case Regex.run(~r/^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/, email) do
        nil ->
          {:error, "Invalid email"}
        [email] ->
          try do
            Regex.run(~r/(\w+)@([\w.]+)/, email) |> validate_email

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# You will need fswatch installed (available in homebrew and friends)
# The command below will run tests and wait until fswatch writes something.
# The --stale flag will only run stale entries, it requires Elixir v1.3.
# fswatch lib/ test/ | mix test --stale --listen-on-stdin
fswatch -0 --latency=0.01 --one-per-batch lib test | mix test --stale test/

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Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

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The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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