ERB is a pretty cool technology, and a great example of the power and versitility of Ruby.

But... it can be a pain to use. Especially once you're used to Rails, which provides a great API for using ERB to render HTML templates. ERB wants a binding, or a proc, and getting those to contain the values you want is a pain.

Enter... EasyRB.

EasyRB provides 3 convenience method that make it easy to render ERB templates:

• String#erb(options = {}) treats the string it is called on as an ERB template, and renders it with the provided options.

• File::erb(filename, options = {}) treats the contents of the file with the given filename as an ERB template, and renders it with the provided options.

• File#erb(options = {}) treats the contents of the file as an ERB template, and renders it with the provided options.

In addition, you can manually create and run an ERB template using:

• EasyRB::Runner.new(erb_template_string).run(options = {})

Each of these methods may take any or all of the same 3 options:

• :context this is the object that is "self" for evaluating the template. If none is provided, then a new Object is used.

• :helpers this is a module or array of modules that provides addition methods when evaluating the template. Note that providing these does not change the :context object.

• :locals this is a hash whose keys will become local variables accessible when evaluating the template. Note that providing these does not change the :context object.

Note: if the same method/key is provided in all three of the options, the priority is locals > helpers > context. This is a Ruby thing, not explicitly a EasyRB thing.

Using context:

Project = Struct.new(:name, :url)
"Started work on #{ name } (at #{ url })".erb(context: Project.new("EasyRB", "http://github.com/mark/easyrb"))
# => "Started work on EasyRB (at http://github.com/mark/easyrb)"

Using helpers:

module FooModule
  def meta_foo
    "foo"
  end
end

module BarModule
  def meta_bar
    "bar"
  end
end

"The first metasyntactic variables are #{ meta_foo } and #{ meta_bar }".erb(helpers: [FooModule, BarModule])
# => "The first metasyntactic variables are foo and bar"

Using locals:

"Hello, #{ first_name } #{ last_name }".erb(locals: { first_name: "Mark", last_name: "Josef" })
# => "Hello, Mark Josef"