ECR Templating: Throwing an error on empty vars

[Alexander Reelsen]

Hey,

if I have the following greeting.ecr file

Greeting, <%= @name %>!

And I am running this class against it

require "ecr"

class Greeting

  def initialize(@name : String | Nil)

  end

  ECR.def_to_s "greeting.ecr"

end

puts Greeting.new(nil).to_s

The output is Greeting, !

Is there any chance to drop this leniency by configuration and throw an exception mentioning an unset variable?

Thanks for any help!

--Alex

[Ary Borenszweig]

Hi!

In your code you are explicitly saying that `@name` allows for String or Nil, so having nil is not an error. There's no way to make it a runtime error: accessing an instance variable will always succeed.

You have a few alternatives:

- just have `@name : String` as the type, that way you get a compile error when passing `nil`

- access name through a method that raises if `@name` is `nil`. You can use `property! name : String` for this.