# ERB

ERB (Embedded RuBy) is a feature of Ruby that enables you to generate any kind of text from templates. This is the default templating engine for Rails and is the one we favour. 

{% hint style="info" %}
ERB is part of the Ruby standard library. You do not need to install any other software to use it. 
{% endhint %}

ERB copies the text portions of the template directly to the generated document, and only processes code that is identified by markers. Most ERB templates only use a combination of two tag markers, each of which cause the enclosed code to be handled in a particular way.

*A tag with an equals* sign indicates that enclosed code is an *expression*, and that **the renderer should substitute the code element with the result of the code** (as a string) when it renders the template. Use an expression to embed a line of code into the template, or to display the contents of a variable:

```
Hello, <%= @name %>.
Today is <%= Time.now.strftime('%A') %>.
```

*Tags without the equals sign* denote that the enclosed code is a *scriptlet*. Each scriptlet is caught and executed, and **the final result of the code is then injected in to the output at the point of the scriptlet**.

Scriptlets are most commonly used for embedding loops or conditional logic into templates:

```markup
<% for  @item in @shopping_list %>
  <%= @item %>
<% end  %>
```

Source: [An Introduction to ERB Templating](https://www.stuartellis.name/articles/erb/).

{% hint style="danger" %}
Even though some HAML templates are still used in some Prospect.io codebases, **you should not create new .haml files**. **We do favor ERB**.
{% endhint %}


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