{ "defaults":
  { "doc":
    [ "A rule to provide defaults."
    , "All targets take their defaults for PATCH from the target"
    , "[\"patch\", \"defaults\"]. This is probably the only sensible"
    , "use of this rule. As targets form a different root, the defaults"
    , "can be provided without changing this directory."
    ]
  , "target_fields": ["base", "toolchain"]
  , "string_fields": ["PATCH", "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 tool PATCH. Note that only artifacts of"
      , "the specified targets are considered (no runfiles etc.). Specifying"
      , "this field extends artifacts from \"base\"."
      ]
    , "PATCH": ["The patch binary to use"]
    , "SYSTEM_TOOLS":
      [ "List of tools (\"PATCH\") that should be taken from"
      , "the system instead of from \"toolchain\" (if specified)."
      ]
    , "PATH":
      [ "Path for looking up the compilers. Individual paths are joined"
      , "with \":\". Specifying this field extends values from \"base\"."
      ]
    }
  , "config_vars": ["ARCH", "HOST_ARCH"]
  , "imports":
    { "base-provides": ["CC", "defaults-base-provides"]
    , "base-provides-++": ["CC", "defaults-base-provides-++"]
    , "base-provides-list": ["CC", "defaults-base-provides-list"]
    , "artifacts_list": ["", "field_artifacts_list"]
    , "nub_left": ["", "nub_left"]
    , "for host": ["transitions", "for host"]
    }
  , "config_transitions":
    {"toolchain": [{"type": "CALL_EXPRESSION", "name": "for host"}]}
  , "expression":
    { "type": "let*"
    , "bindings":
      [ ["PATCH", {"type": "FIELD", "name": "PATCH"}]
      , ["PATH", {"type": "FIELD", "name": "PATH"}]
      , ["provider", "PATCH"]
      , [ "PATCH"
        , { "type": "if"
          , "cond": {"type": "var", "name": "PATCH"}
          , "then": {"type": "var", "name": "PATCH"}
          , "else": {"type": "CALL_EXPRESSION", "name": "base-provides"}
          }
        ]
      , ["provider", "PATH"]
      , [ "PATH"
        , { "type": "++"
          , "$1":
            [ {"type": "var", "name": "PATH"}
            , {"type": "CALL_EXPRESSION", "name": "base-provides-++"}
            ]
          }
        ]
      , [ "PATH"
        , { "type": "let*"
          , "bindings": [["list", {"type": "var", "name": "PATH"}]]
          , "body": {"type": "CALL_EXPRESSION", "name": "nub_left"}
          }
        ]
      , ["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"}]
              , { "type": "if"
                , "cond": {"type": "FIELD", "name": "PATCH"}
                , "then":
                  [ { "type": "singleton_map"
                    , "key": "PATCH"
                    , "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": ["PATCH", "PATH", "ENV", "TOOLCHAIN", "NON_SYSTEM_TOOLS"]
        }
      }
    }
  }
, "file":
  { "doc": ["Replace a file, logically in place, by a patched version"]
  , "target_fields": ["src", "patch"]
  , "config_vars": ["PATCH", "ENV"]
  , "implicit": {"patch-defaults": ["defaults"]}
  , "field_doc":
    { "src":
      [ "The single source file to patch, typically an explicit file reference."
      ]
    , "patch": ["The patch to apply."]
    , "patch-defaults": ["The patch binary (and toolchain) to use"]
    }
  , "artifacts_doc":
    ["The patched file, staged to the position the of the original file"]
  , "runfiles_doc": ["Same as artifacts"]
  , "imports":
    { "stage_field": ["./", "..", "stage_singleton_field"]
    , "stage_artifact": ["./", "..", "stage_artifact_to_singleton_field"]
    , "default-PATCH": "default-PATCH"
    , "default-TOOLCHAIN": "default-TOOLCHAIN"
    , "default-ENV": "default-ENV"
    , "default-PATH": "default-PATH"
    , "default-NON_SYSTEM_TOOLS": "default-NON_SYSTEM_TOOLS"
    }
  , "expression":
    { "type": "let*"
    , "bindings":
      [ ["TOOLCHAIN_DIR", "toolchain"]
      , ["TOOLCHAIN", {"type": "CALL_EXPRESSION", "name": "default-TOOLCHAIN"}]
      , [ "TOOLCHAIN"
        , { "type": "to_subdir"
          , "subdir": {"type": "var", "name": "TOOLCHAIN_DIR"}
          , "$1": {"type": "var", "name": "TOOLCHAIN"}
          }
        ]
      , [ "NON_SYSTEM_TOOLS"
        , {"type": "CALL_EXPRESSION", "name": "default-NON_SYSTEM_TOOLS"}
        ]
      , [ "PATCH"
        , { "type": "var"
          , "name": "PATCH"
          , "default":
            { "type": "join"
            , "$1":
              { "type": "++"
              , "$1":
                [ { "type": "if"
                  , "cond":
                    { "type": "lookup"
                    , "key": "PATCH"
                    , "map": {"type": "var", "name": "NON_SYSTEM_TOOLS"}
                    }
                  , "then":
                    ["./", {"type": "var", "name": "TOOLCHAIN_DIR"}, "/"]
                  }
                , {"type": "CALL_EXPRESSION", "name": "default-PATCH"}
                ]
              }
            }
          }
        ]
      , [ "ENV"
        , { "type": "map_union"
          , "$1":
            [ {"type": "CALL_EXPRESSION", "name": "default-ENV"}
            , {"type": "var", "name": "ENV", "default": {"type": "empty_map"}}
            ]
          }
        ]
      , [ "ENV_PATH"
        , { "type": "lookup"
          , "map": {"type": "var", "name": "ENV"}
          , "key": "PATH"
          }
        ]
      , [ "ENV"
        , { "type": "map_union"
          , "$1":
            [ {"type": "var", "name": "ENV"}
            , { "type": "singleton_map"
              , "key": "PATH"
              , "value":
                { "type": "join"
                , "separator": ":"
                , "$1":
                  { "type": "++"
                  , "$1":
                    [ {"type": "CALL_EXPRESSION", "name": "default-PATH"}
                    , { "type": "if"
                      , "cond": {"type": "var", "name": "ENV_PATH"}
                      , "then": [{"type": "var", "name": "ENV_PATH"}]
                      }
                    ]
                  }
                }
              }
            ]
          }
        ]
      , [ "orig"
        , { "type": "let*"
          , "bindings": [["fieldname", "src"], ["location", "orig"]]
          , "body": {"type": "CALL_EXPRESSION", "name": "stage_field"}
          }
        ]
      , [ "patch"
        , { "type": "let*"
          , "bindings": [["fieldname", "patch"], ["location", "patch"]]
          , "body": {"type": "CALL_EXPRESSION", "name": "stage_field"}
          }
        ]
      , [ "script"
        , { "type": "singleton_map"
          , "key": "run_patch.sh"
          , "value":
            { "type": "BLOB"
            , "data":
              { "type": "join"
              , "separator": "\n"
              , "$1":
                [ "set -e"
                , "cp orig patched"
                , "chmod +w patched"
                , { "type": "join"
                  , "$1":
                    [ { "type": "join_cmd"
                      , "$1":
                        [ {"type": "var", "name": "PATCH", "default": "patch"}
                        , "patched"
                        , "patch"
                        ]
                      }
                    , " >log || (cat log && exit 1)"
                    ]
                  }
                ]
              }
            }
          }
        ]
      , [ "inputs"
        , { "type": "map_union"
          , "$1":
            [ {"type": "var", "name": "orig"}
            , {"type": "var", "name": "patch"}
            , {"type": "var", "name": "TOOLCHAIN"}
            , {"type": "var", "name": "script"}
            ]
          }
        ]
      , [ "patched"
        , { "type": "ACTION"
          , "inputs": {"type": "var", "name": "inputs"}
          , "outs": ["patched"]
          , "cmd": ["sh", "./run_patch.sh"]
          , "env": {"type": "var", "name": "ENV"}
          }
        ]
      , [ "result"
        , { "type": "let*"
          , "bindings":
            [ ["artifact", {"type": "var", "name": "patched"}]
            , ["fieldname", "src"]
            ]
          , "body": {"type": "CALL_EXPRESSION", "name": "stage_artifact"}
          }
        ]
      ]
    , "body":
      { "type": "RESULT"
      , "artifacts": {"type": "var", "name": "result"}
      , "runfiles": {"type": "var", "name": "result"}
      }
    }
  }
}