_Metaprogramming Elixir by The Pragmatic Programmer_468 x 60 copy.png

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elixir

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Get introduced to the concept of metaprogramming. Learn how to level up your programming skills by discovering the full potential of the macro system in Elixir. Understand the ins and outs of metaprogramming at a fundamental level and write incredible libraries by doing more with less code.

Metaprogramming in Elixir

```
test "Hello in French" do
assert I18n.t("en", "flash.hello", first: "John", last: "Smith") ==
    "hello John Smith!"
end

```
test "Hello in French" do
assert I18n.t("fr", "flash.notice.hello", first: "Jason", last: "S") ==
    "Salut Jason S!"
end

```
test "Hello in French" do
assert I18n.t("fr", "flash.notice.hello", name: "John S") ==
    "hello Jason S!"
end

Take the following module as reference:
```
defmodule I18n do
  use Translator

  locale "en",
    flash: [
      hello: "Hello %{first} %{last}!",
      bye: "Bye, %{name}!"
    ],
    users: [
      name: "Ronald",
    ]
  locale "fr",
    flash: [
      hello: "Salut %{first} %{last}!",
    ],
    users: [
      name: "Ronald",
    ]
```
Which test case could be used to check if `hello` is translated correctly in `fr`?

Take the following module as reference:
<pre><code>defmodule I18n do
 use Translator

 locale &quot;en&quot;,
 flash: [
 hello: &quot;Hello %{first} %{last}!&quot;,
 bye: &quot;Bye, %{name}!&quot;
 ],
 users: [
 name: &quot;Ronald&quot;,
 ]
 locale &quot;fr&quot;,
 flash: [
 hello: &quot;Salut %{first} %{last}!&quot;,
 ],
 users: [
 name: &quot;Ronald&quot;,
 ]
</code></pre>
Which test case could be used to check if <code>hello</code> is translated correctly in <code>fr</code>?

```
test "Wizards test" do
assert I18n.t("hp", "flash.disclaimer.notice", adjective: "amazing") ==
    "Wizards are amazing!"
end

```
test "Wizards test" do
assert I18n.t("wizards", "flash.notice", adjective: "amazing") ==
    "Wizards are amazing!"
end

```
test "Wizards test" do
assert I18n.t("hp", "flash.disclaimer", "notice", adjective: "amazing") ==
    "Wizards are amazing!"
end

Take the following module as reference:
```
defmodule I18n do
  use Translator

  locale "hp",
    flash: [
      disclaimer: [
        notice: "Wizards are %{adjective},
      ],
    ],
    wizards: [
      name: "Harry",
    ]
```
Which of the following test cases could be used for testing if `notice`  gives the right output?

Take the following module as reference:
<pre><code>defmodule I18n do
 use Translator

 locale &quot;hp&quot;,
 flash: [
 disclaimer: [
 notice: &quot;Wizards are %{adjective},
 ],
 ],
 wizards: [
 name: &quot;Harry&quot;,
 ]
</code></pre>
Which of the following test cases could be used for testing if <code>notice</code> gives the right output?

```
test "Wizards test" do
assert I18n.t("hp", "wizards.name", adjective: "amazing") ==
    "Wizards"
end

```
test "Wizards test" do
assert I18n.t("hp", "wizards.disclaimer", name: "Harry") ==
    "Harry"
end

```
test "Wizards test" do
assert I18n.t("hp", "wizards.name") ==
    "Harry"
end

Take the following module as reference:
```
defmodule I18n do
  use Translator

  locale "hp",
    flash: [
      disclaimer: [
        notice: "Wizards are %{adjective},
      ],
    ],
    wizards: [
      name: "Harry",
    ]
```
Which of the following test cases could be used for testing if the `wizards` field gives the correct output?

Take the following module as reference:
<pre><code>defmodule I18n do
 use Translator

 locale &quot;hp&quot;,
 flash: [
 disclaimer: [
 notice: &quot;Wizards are %{adjective},
 ],
 ],
 wizards: [
 name: &quot;Harry&quot;,
 ]
</code></pre>
Which of the following test cases could be used for testing if the <code>wizards</code> field gives the correct output?

Which of the following testing types is considered top-level?

Which of the following testing types is considered top-level?

Which category does the following test case belong to?
```
test "t/3 returns {:error, :no_translation} when translation is missing" do assert I18n.t("en", "flash.not_exists") == {:error, :no_translation}
end
```

Which category does the following test case belong to?
<pre><code>test &quot;t/3 returns {:error, :no_translation} when translation is missing&quot; do assert I18n.t(&quot;en&quot;, &quot;flash.not_exists&quot;) == {:error, :no_translation}
end
</code></pre>

What is the major drawback of using too many modules when running tests in Elixir?

What is the major drawback of using too many modules when running tests in Elixir?

Introduction

The Language of Macros

Extending Elixir with Metaprogramming

Advanced Compile-Time Code Generation

Code Generation from Git API

How to Test Macros

Create an HTML Domain-Specific Language

With Great Power Comes Great Responsibility (and Fun!)

Test Your Knowledge!