interpolate variable with non-module HCL files

[talset]

Currently, variable interpolation works when the Terraform code is structured as module (like here

But the estimation will fail with a simple TF file such:

provider "aws" {
  region = "eu-west-1"
}

variable "front_ebs_optimized" {
  default = false
}

resource "aws_instance" "web" {
  ami           = data.aws_ami.ubuntu.id
  instance_type = "m3.xlarge"

  ebs_optimized = var.front_ebs_optimized
}

Because the variable is not replaced by the real value

expected

Implement the variable interpolation on non-module terraform code