{ "defaults":
  { "doc":
    [ "A rule to provide defaults for foreign rules."
    , "All foreign rules take their defaults for MAKE, CMAKE, etc from"
    , "the target [\"CC/foreign\", \"defaults\"]."
    ]
  , "target_fields": ["base", "toolchain"]
  , "string_fields": ["MAKE", "CMAKE", "PATH", "SYSTEM_TOOLS"]
  , "field_doc":
    { "base": ["Other targets (using the same rule) to inherit values from."]
    , "toolchain":
      [ "Optional toolchain directory. A collection of artifacts that provide"
      , "the tools MAKE, CMAKE. Note that only artifacts of"
      , "the specified targets are considered (no runfiles etc.). Specifying"
      , "this field extends artifacts from \"base\"."
      ]
    , "MAKE": ["The make binary to use"]
    , "CMAKE": ["The cmake binary to use"]
    , "SYSTEM_TOOLS":
      [ "List of tools (\"MAKE\", \"CMAKE\") that should be taken from"
      , "the system instead of from \"toolchain\" (if specified)."
      ]
    , "PATH":
      [ "Path for looking up the tools. Individual paths are joined with"
      , "with \":\". Specifying this field extends values from \"base\"."
      ]
    }
  , "config_vars": ["ARCH", "HOST_ARCH"]
  , "imports":
    { "base-provides": ["./", "..", "defaults-base-provides"]
    , "base-provides-++": ["./", "..", "defaults-base-provides-++"]
    , "base-provides-list": ["./", "..", "defaults-base-provides-list"]
    , "artifacts_list": ["./", "../..", "field_artifacts_list"]
    , "for host": ["transitions", "for host"]
    }
  , "config_transitions":
    {"toolchain": [{"type": "CALL_EXPRESSION", "name": "for host"}]}
  , "expression":
    { "type": "let*"
    , "bindings":
      [ ["MAKE", {"type": "FIELD", "name": "MAKE"}]
      , ["CMAKE", {"type": "FIELD", "name": "CMAKE"}]
      , ["PATH", {"type": "FIELD", "name": "PATH"}]
      , ["provider", "MAKE"]
      , [ "MAKE"
        , { "type": "if"
          , "cond": {"type": "var", "name": "MAKE"}
          , "then": {"type": "var", "name": "MAKE"}
          , "else": {"type": "CALL_EXPRESSION", "name": "base-provides"}
          }
        ]
      , ["provider", "CMAKE"]
      , [ "CMAKE"
        , { "type": "if"
          , "cond": {"type": "var", "name": "CMAKE"}
          , "then": {"type": "var", "name": "CMAKE"}
          , "else": {"type": "CALL_EXPRESSION", "name": "base-provides"}
          }
        ]
      , ["provider", "PATH"]
      , [ "PATH"
        , { "type": "nub_left"
          , "$1":
            { "type": "++"
            , "$1":
              [ {"type": "var", "name": "PATH"}
              , {"type": "CALL_EXPRESSION", "name": "base-provides-++"}
              ]
            }
          }
        ]
      , ["provider", "ENV"]
      , ["default", {"type": "empty_map"}]
      , ["ENV", {"type": "CALL_EXPRESSION", "name": "base-provides"}]
      , ["provider", "NON_SYSTEM_TOOLS"]
      , ["default", {"type": "empty_map"}]
      , [ "NON_SYSTEM_TOOLS"
        , { "type": "map_union"
          , "$1":
            { "type": "++"
            , "$1":
              [ {"type": "CALL_EXPRESSION", "name": "base-provides-list"}
              , { "type": "if"
                , "cond": {"type": "FIELD", "name": "MAKE"}
                , "then":
                  [ { "type": "singleton_map"
                    , "key": "MAKE"
                    , "value":
                      { "type": "if"
                      , "cond": {"type": "FIELD", "name": "toolchain"}
                      , "then": true
                      , "else": false
                      }
                    }
                  ]
                }
              , { "type": "if"
                , "cond": {"type": "FIELD", "name": "CMAKE"}
                , "then":
                  [ { "type": "singleton_map"
                    , "key": "CMAKE"
                    , "value":
                      { "type": "if"
                      , "cond": {"type": "FIELD", "name": "toolchain"}
                      , "then": true
                      , "else": false
                      }
                    }
                  ]
                }
              , { "type": "foreach"
                , "range": {"type": "FIELD", "name": "SYSTEM_TOOLS"}
                , "var": "tool"
                , "body":
                  { "type": "singleton_map"
                  , "key": {"type": "var", "name": "tool"}
                  , "value": false
                  }
                }
              ]
            }
          }
        ]
      , ["provider", "TOOLCHAIN"]
      , ["default", {"type": "empty_map"}]
      , [ "TOOLCHAIN"
        , { "type": "disjoint_map_union"
          , "msg": "toolchain artifacts may not overlap"
          , "$1":
            { "type": "++"
            , "$1":
              [ {"type": "CALL_EXPRESSION", "name": "base-provides-list"}
              , { "type": "if"
                , "cond": {"type": "FIELD", "name": "toolchain"}
                , "then":
                  { "type": "let*"
                  , "bindings":
                    [ ["fieldname", "toolchain"]
                    , [ "transition"
                      , {"type": "CALL_EXPRESSION", "name": "for host"}
                      ]
                    ]
                  , "body":
                    {"type": "CALL_EXPRESSION", "name": "artifacts_list"}
                  }
                }
              ]
            }
          }
        ]
      ]
    , "body":
      { "type": "RESULT"
      , "provides":
        { "type": "env"
        , "vars":
          ["MAKE", "CMAKE", "PATH", "ENV", "TOOLCHAIN", "NON_SYSTEM_TOOLS"]
        }
      }
    }
  }
}