Programmer Passport: Elixir

Structs, Maps, and Public APIs

When you’re building software that’s bigger than a side project, two language features often come into conflict: type safety and API design. When you’re building a structure with type safety, the idea is to give the compiler all of the data that you can so that the compiler can catch mistakes.

So, let’s think about the API for our SVG library. So far, the main output for our Shape will be an SVG string. That’s easy.

Add this function to your shape.ex file:

def to_svg(shape) do
  """
  <polygon
    points="#{render_points(shape)}"
    style="#{render_style(shape)}"
  />
  """
end

That’s a simple function. The main syntactic trick is a feature called the heredoc, which uses """ to surround multiline ...