Add support for Resources and Modules as Values

[mfcastellani]

Building on this capability, Terraform 0.12 now permits using entire resources as object values within configuration, including returning them as outputs and passing them as input variables:

Configuration for Terraform 0.12

output "vpc" {
  value = aws_vpc.example
}

The type of this output value is an object type derived from the schema of the aws_vpc resource type. The calling module can then access attributes of this result in the same way as the returning module would use aws_vpc.example, such as module.example.vpc.cidr_block.

This capability also works for modules themselves, with an expression like module.vpc evaluating to an object value with attributes corresponding to the modules's named outputs.

https://www.hashicorp.com/blog/terraform-0-12-rich-value-types

[thiagoarrais]

This parses in main branch. What is the expected behaviour here? Should the parser output differentiate between references and strings? How?

  it 'parses resource reference as value' do
    hcl_string = 'output "foo" {' \
                 'value = bar_resource.baz' \
                 '}'
    expect(HCL::Checker.parse hcl_string).to eq({
      "output" => {
        "foo" => {
          "value" => "bar_resource.baz", 
        }
      }
    })
  end

[mfcastellani]

Parser should be able to parse data with or without quotes. Currently this break the parser:

variable "networks" {
  type = map(object({
    network_number    = number
    availability_zone = string
    tags              = map(string)
  }))
}

But since 0.12 this is a valid code and should be parsed correctly