On Chapter 3 - Page 78, the beginning of the page has this code here:
@doc """
Maybe it is missing to put the Pento context before Catalog.Product.Query?
"""
defmodule Catalog.Product.Query do
...
def base_product_query, do: Product
def cheaper_than(query, price), do: from in query, where...
def cheap_product_skus(price)
base_product_query()
|> chaper_than(price)
|> skus
end
...
end
And for the code almost to the bottom, has some typos. Like:
defmodule Pento.Catalog do
alias Catalog.Product.Query
alias Pento.Repo
def run_query(query) do
{:ok, list} = Repo.all(query)
list
end
def send_sale_skus(query) do
query
|> Product.cheap_product_skus(25.00) # Typo: Query.cheap_product_skus(25.00)
|> run_query
|> Service.send_bargains # Question: the name of the module it is only Service?
end
end
Also, for the next page 79, has more typos too, like:
defmodule Pento.Catalog do
alias Catalog.Product.Query
alias Pento.Repo
@doc """
For the Repo.all API, has only three options:
1. Empty List without any items.
2. List with one or more items.
3. Query doesn't work and raise an error.
"""
def run_query(query) do
Repo.all(query)
end
def send_sale_skus(query) do
query
|> Product.cheap_product_skus(25.00) # Typo: Query.cheap_product_skus(25.00)
|> run_query
end
def send_sale_skus(query)
with {:ok, products} <- send_sale_skus(query), # this line of code here, never pattern matching
{:ok, response} <- Service.send_bargains(products) do # when this line of code it fails? Returns as a tuple with {:error, reason} ?
response
else
# if some error or cas doesn't pattern match in with conditions it will failure here a raise an error with unclause matching.
{:error, reason} ->
IO.puts "Error sending sale skus: #{reason}"
end
end
end
After words this is my feedback even these code as an example, and not intended to use. Besides, I use common comments as #
, and some others I use @doc
to get my point of view.