crbelaus’s gists

crbelaus / slugify.ex

Created March 11, 2024 08:22

Slugify a string in Elixir

	# Copied from https://mudssrali.com/blog/slugify-a-string-in-elixir
	# and then modified to drop leading and trailing dashes.

	defmodule String do
	# 1. Convert a string to downcase
	# 2. Remove any leading and trailing spaces
	# 3. Convert graphemes to normal characters (e.g. á, é)
	# 4. Replace non-alphanumeric characters with an empty string
	# 5. Replace multiple spaces or dashes with a single dash
	# 6. Remove any leading and trailing dashes

crbelaus / trans1_runtime_errors.ex

Last active June 29, 2019 12:53

Shows an example of Trans 1.0 runtinme errors

	# Trans 1.0 did not perform safety checks when building queries.
	# Adding conditions on a non-existing field would result un runtime errors.
	iex> Article
	...> \|> Article.with_translation(:es, :fake, "this field does not exist")
	...> \|> Repo.all
	** (ArgumentError) The field `fake` is not declared as translatable

crbelaus / trans1_interface_pollution.ex

Last active June 29, 2019 12:54

Shows an example of a module using Trans 1.0 and it's added functions

	# Using tab to autocomplete shows the functions added by Trans
	# Those functions pollute the module interface and add database
	# and query concerns to the schema module
	iex(5)> Article.
	changeset/1 changeset/2 with_translation/4
	with_translation/5 with_translations/2 with_translations/3

crbelaus / trans1_querybuilder_example.ex

Created April 14, 2017 11:35

Shows an example of the QueryBuilder of Trans 1.0

	# Fetch articles titled "La République" in French
	iex> Article
	...> \|> Trans.QueryBuilder.with_translation(:fr, :title, "La République")
	...> \|> Repo.all
	# SELECT a0."id", a0."title", a0."body", a0."translations"
	# FROM "articles" AS a0
	# WHERE (a0."translations"->"fr"->>"title" = "La République")

crbelaus / trans2_querybuilder_examples.ex

Last active June 29, 2019 12:56

Shows examples of the Trans 2.0 QueryBuilder

	# Fetch Articles titled "Trans" in French and having an English comment
	# containing the word "good"
	iex> Repo.all(from a in Article,
	...> join: c in assoc(a, :comments),
	...> where: translated(Article, a.title, :fr) == "Trans",
	...> where: ilike(translated(Comment, c.comment, :en), "good"))
	# SELECT a0."id", a0."title", a0."body", a0."translations"
	# FROM "articles" AS a0
	# INNER JOIN "comments" AS c1 ON a0."id" = c1."article_id"
	# WHERE ((a0."translations"->"fr"->>"title") = "Trans")

crbelaus / if_anaphoric_invocation.exs

Last active June 29, 2019 13:02

Shows an example of IEx invocation of `if_anaphoric.ex`.

	iex(1)> require Anaphora
	Anaphora

	iex(2)> Anaphora.if Universe.response_to_everything do
	...(2)> # La variable 'it' se crea automaticamente durante la
	...(2)> # macro expansión.
	...(2)> Universe.proclaim it
	...(2)> end
	"Whoa! The data is 42"

crbelaus / if_anaphoric.ex

Last active June 29, 2019 13:01

Implements an anaphoric if as `Anaphora.if` and shows how it can be used. #anaphora

	defmodule Universe do
	def response_to_everything do
	:timer.sleep(5000) # Simulate complex calculations for 5 seconds
	42
	end

	def proclaim(data), do: "Whoa! The data is #{data}"
	end

	defmodule Anaphora do

crbelaus / if_scoped_variable.exs

Last active June 29, 2019 13:00

A simple example of a memoization of a complex calculation. This example shows how the `with` construction can be used to create a new scope to which the variable `result` is bounded and not available outside. #anaphora

	defmodule Universe do
	def response_to_everything do
	:timer.sleep(5000) # Simulate complex calculations for 5 seconds
	42
	end

	def proclaim(data), do: "Whoa! The data is #{data}"
	end

	with result <- Universe.response_to_everything do

crbelaus / if_memoized_variable.exs

Last active June 29, 2019 12:59

A simple example memoization of a complex calculation that gets used twice. This example also shows how the original variable is bounded to the parent scope and available after the `if` execution finishes. #anaphora

	defmodule Universe do
	def response_to_everything do
	:timer.sleep(5000) # Simulate complex calculations for 5 seconds
	42
	end

	def proclaim(data), do: "Whoa! The data is #{data}"
	end

crbelaus / fibo.exs

Last active February 7, 2016 11:48

The exercise of @miguelff (https://gist.github.com/miguelff/08d87b5823c55b82bc02) woke up my curiosity about how tail recursion optimization could improve the performance over the "traditional" recursive Fibonacci solution.

	defmodule Fibo do
	def recursive(n) when n <= 2, do: 1
	def recursive(n), do: recursive(n-1) + recursive(n-2)

	def tail_rec(n, prev \\ 0, current \\ 1)
	def tail_rec(0, prev, _), do: prev
	def tail_rec(n, prev, current), do: tail_rec(n - 1, current, current + prev)
	end

	defmodule Benchmark do

Cristian Álvarez Belaustegui crbelaus