simulation_name:
  description:
    The name of the current simulation
  value:
    type: string
    default: ILAMB

config_file:
  description:
    Path to the ILAMB configuration file
  value:
    type: string
    default: ilamb.cfg

ilamb_root:
  description:
    Path to the ILAMB benchmark data and model output repository
  value:
    type: string
    default: /nas/data/ilamb

model_root:
  description:
    Directory relative to ILAMB_ROOT containing model outputs
  value:
    type: string
    default: MODELS

build_dir:
  description:
    Name of ILAMB build directory
  value:
    type: string
    default: _build

define_regions:
  description:
    File defining custom analysis region
  value:
    type: file
    default: off
    files:
      - off

regions:
  description:
    Geographical regions over which analysis is performed
  value:
    type: list
    default: []

models:
  description:
    A list of models to benchmark
  value:
    type: list
    default: []

confrontations:
  description:
    A list of confrontations to run
  value:
    type: list
    default: []

simulation_name:
  description:
    The name of the current simulation
  value:
    type: string
    default: ILAMB

config_file:
  description:
    Path to the ILAMB configuration file
  value:
    type: string
    default: ilamb.cfg

ilamb_root:
  description:
    Path to the ILAMB benchmark data and model output repository
  value:
    type: string
    default: /nas/data/ilamb

model_root:
  description:
    Directory relative to ILAMB_ROOT containing model outputs
  value:
    type: string
    default: MODELS

build_dir:
  description:
    Name of ILAMB build directory
  value:
    type: string
    default: _build

define_regions:
  description:
    File (netCDF or text) defining custom analysis region
  value:
    type: string
    default: ''

regions:
  description:
    Geographical regions over which analysis is performed
  value:
    type: list
    default: []

models:
  description:
    A list of models to benchmark
  value:
    type: list
    default: []

confrontations:
  description:
    A list of confrontations to run
  value:
    type: list
    default: []

Change define_regions parameter to type string
Change define_regions parameter to type string

I'll make a private parameter of type file in the WMT metadata and
map its value to `define_regions` in the pre-stage hook.

This will be a nicer strategy for model developers because they
won't necessarily know about the file parameter type.
