How to create/publish an Elixir package on Hex.pm

[nelsonic]

We don't have a beginner-friendly write-up for creating Hex.pm packages; we need a concise guide.

GOTO: /code-reuse-hexpm.md

Todo: Done!

Consolidate these:

• https://hex.pm/docs/publish
• https://ieftimov.com/writing-elixir-library
• http://whatdidilearn.info/2018/06/17/publishing-elixir-packages-to-hex.html
• https://medium.com/kkempin/how-to-create-and-publish-hex-pm-package-elixir-90cb33e2592d
• https://medium.com/blackode/how-to-write-elixir-packages-and-publish-to-hex-pm-8723038ebe76
• Re-position the section after learning syntax https://github.com/dwyl/learn-elixir/pull/107/files https://github.com/dwyl/learn-elixir#publishing

How to Use the Package Locally Before Publishing it to hex.pm

• https://stackoverflow.com/questions/28185003/using-a-package-locally-with-hex-pm

[nelsonic]

Create a Mix Project and Run Elixir Code

https://pragmaticstudio.com/tutorials/create-elixir-mix-project-and-run-code

This is a good intro to using mix new and running the code. 👍

[nelsonic]

Continue:

• https://github.com/dwyl/learn-elixir/blob/code-reuse-publishing-to-hexpm-issue%2395/code-reuse-hexpm.md
• https://hexdocs.pm/jason/Jason.html
• https://davidtang.io/2019/01/22/decoding-json-into-elixir-structs.html

[nelsonic]

Decided I didn't need to introduce the complexity at this stage. 😕
Wrote my own recursive function to test all properties in quotes.json ✅

Meanwhile I've found a way of testing Quotes.random() using the Brithday Paradox! 😉
https://betterexplained.com/articles/understanding-the-birthday-paradox/

[nelsonic]

Lovely docs for free!:

[nelsonic]

See: https://hex.pm/packages/quotes

Docs: https://hexdocs.pm/quotes/Quotes.html

[nelsonic]

TIL: how to pass a function as a parameter in Elixir:

https://stackoverflow.com/questions/22562192/how-do-you-pass-a-function-as-a-parameter-in-elixir

Use &Module.function/arity to pass it, and .(…) to call it.

For example:

def my_hof(f) # "hof" = higher order function (in case you're wondering...)
    f.([1, 2, 3], &(&1 * 2))
end

my_hof(&Enum.map/2)

in my example I modified the code from:

  # This recursive function calls Quotes.random until a quote is repeated
  def get_random_quote_until_collision(random_quotes_list) do
    random_quote = Quotes.random()
    if Enum.member?(random_quotes_list, random_quote) do
      random_quotes_list
    else
      get_random_quote_until_collision([random_quote | random_quotes_list])
    end
  end

  test "Quotes.random returns a random quote" do
    # execute Quotes.random and accumulate until a collision occurs
    random_quotes_list = get_random_quote_until_collision([])
    # this is the birthday paradox at work! ;-)
    # IO.inspect Enum.count(random_quotes_list)
    assert Enum.count(random_quotes_list) < 200
  end

To:

  # This recursive function calls func (argument) until a quote is repeated
  def get_quotes_until_collision(random_quotes_list, func) do
    random_quote = func.()
    if Enum.member?(random_quotes_list, random_quote) do
      random_quotes_list
    else
      get_quotes_until_collision([random_quote | random_quotes_list], func)
    end
  end

  test "Quotes.random returns a random quote" do
    # execute Quotes.random and accumulate until a collision occurs
    random_quotes_list = get_quotes_until_collision([], &Quotes.random/0)
    # this is the birthday paradox at work! ;-)
    # IO.inspect Enum.count(random_quotes_list)
    assert Enum.count(random_quotes_list) < 200
  end

[nelsonic]

I've written 5k words in https://github.com/dwyl/learn-elixir/blob/code-reuse-publishing-to-hexpm-issue%2395/code-reuse-hexpm.md and https://github.com/dwyl/quotes and I feel it's close to being finished ... but I need to work on something else for a bit ...

#brb

[nelsonic]

Used the quotes package in https://github.com/dwyl/phoenix-content-negotiation-tutorial so I think we can consider this tutorial complete. Assigning the PR to @SimonLab #146 🙏

[nelsonic]

GOTO: /code-reuse-hexpm.md