Get name of the variable with method

[dshatokhin]

Hi! I'm trying to define a method for outputting the the variable name with as a string, with some additions:

class Variable {
  type: String?
  default: String?

  function format(): String = "something here"
}

vm_size = new Variable {
  type = "string"
  default = "1xCPU-1GB"
}

formatted_variable_name = vm_size.format()
// formatted_variable_name == "${var.vm_size}"

Reading the package docs for reflect didn't help me to find a solution.
Is it even possible to implement?

[bioball]

You'd have to pass the name in somehow to class Variable.

The simplest approach with the least amount of magic is to pass it in explicitly:

class Variable {
  type: String?
  default: String?
  name: String

  function format(): String = "${var.\(name)}"
}

vm_size = new Variable {
  type = "string"
  default = "1xCPU-1GB"
  name = "vm_size"
}

formatted_variable_name = vm_size.format()
// formatted_variable_name == "${var.vm_size}"

However, there's definitely ways to add some "magic" to fill this in. For example, here's an approach that uses toMap():

class Variable {
  type: String?
  default: String?
  name: String

  function formatted() = "${var.\(name)}"
}

vm_size: Variable = new {
  type = "string"
  default = "1xCPU-1GB"
}

// create a version of this module where all `Variable` values have a `name` filled in based
// on the propertyy name.
local hydratedVars: module = 
  module
    .toMap()
    .mapValues((key, value) ->
      if (value is Variable) (value) { name = key }
      else value
    )
  .toTyped(module.getClass())

output {
  // set the module's output to the hydrated module
  value = hydratedVars
}

[dshatokhin]

This works perfectly, thanks for a clever solution 😊