Roll Your Own

As discussed earlier, Papercraft templates are defined as lambdas, and consequently they are completely self-contained and can be used in any context and in any situation. This also means that you can use it in conjunction with any web framework, and in any place in your app’s code.

That said, you might encounter problems when trying to integrate Papercraft templates with helper functions that might be available to you when using ERB templates in frameworks such as Rails or Hanami. Other than that, there’s really no limit to how you can use Papercraft for your HTML templates.

Keep it Pure

Papercraft templates, like all Ruby lambdas, are also closures, which means they capture the local binding where they are defined, and therefore have access to any local variable, as well as the local receiver (a.k.a. self). This means that you can reference any local or instance variable, or explicitly call methods on self inside your templates.

However, it is better to use explicit arguments as discussed in the Writing Templates section, as this greatly increases the reusability of your templates. This also makes it easier to eventually refactor your code:

# instead of this:
def greet
  Papercraft.html {
    h1 "Hello, #{@name}!"
  }
end

# do this:
def greet
  Papercraft.html(
    ->(name) {
      h1 "Hello, #{name}!"
    },
    @name
  )
end

The same goes for calling methods on self:

# instead of this:
def template
  -> {
    h1 self.title
  }
end

# do this:
TEMPLATE = ->(ctx:) {
  h1 ctx.title
}

def template
  Papercraft.apply(TEMPLATE, ctx: self)
end