{ "staged":
  { "doc": ["Stage data to a logical subdirectory."]
  , "target_fields": ["srcs"]
  , "string_fields": ["stage"]
  , "field_doc":
    { "srcs": ["The files to be staged"]
    , "stage":
      [ "The logical directory to stage the files to."
      , "Individual directory components are joined with \"/\"."
      ]
    }
  , "artifacts_doc":
    [ "The runfiles of the \"srcs\" targets staged to the directory"
    , "specified in \"stage\"."
    ]
  , "runfiles_doc": ["Same as artifacts"]
  , "imports": {"runfiles": ["./", "..", "field_runfiles"]}
  , "expression":
    { "type": "let*"
    , "bindings":
      [ [ "stage"
        , { "type": "join"
          , "separator": "/"
          , "$1": {"type": "FIELD", "name": "stage"}
          }
        ]
      , [ "srcs"
        , { "type": "let*"
          , "bindings": [["fieldname", "srcs"]]
          , "body": {"type": "CALL_EXPRESSION", "name": "runfiles"}
          }
        ]
      , [ "staged"
        , { "type": "to_subdir"
          , "subdir": {"type": "var", "name": "stage"}
          , "$1": {"type": "var", "name": "srcs"}
          }
        ]
      ]
    , "body":
      { "type": "RESULT"
      , "artifacts": {"type": "var", "name": "staged"}
      , "runfiles": {"type": "var", "name": "staged"}
      }
    }
  }
}