{ "template":
  { "doc": ["Create a pandoc template with arguments"]
  , "string_fields": ["name", "args"]
  , "target_fields": ["data", "lua filters"]
  , "field_doc":
    { "name": ["Name of the template to use"]
    , "args": ["Additional pandoc arguments"]
    , "data": ["Template data files"]
    , "lua filters": ["Files that should be used as lua filters"]
    }
  , "expression":
    { "type": "let*"
    , "bindings":
      [ [ "data"
        , { "type": "disjoint_map_union"
          , "msg": "Data files may not conflict"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "data"}
            , "body":
              { "type": "map_union"
              , "$1":
                [ {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "x"}}
                , { "type": "DEP_ARTIFACTS"
                  , "dep": {"type": "var", "name": "x"}
                  }
                ]
              }
            }
          }
        ]
      , [ "lua filters"
        , { "type": "disjoint_map_union"
          , "msg": "Lua filters may not conflict"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "lua filters"}
            , "body":
              { "type": "map_union"
              , "$1":
                [ {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "x"}}
                , { "type": "DEP_ARTIFACTS"
                  , "dep": {"type": "var", "name": "x"}
                  }
                ]
              }
            }
          }
        ]
      ]
    , "body":
      { "type": "RESULT"
      , "artifacts": {"type": "var", "name": "data"}
      , "runfiles": {"type": "var", "name": "data"}
      , "provides":
        { "type": "map_union"
        , "$1":
          [ { "type": "singleton_map"
            , "key": "template-name"
            , "value":
              {"type": "join", "$1": {"type": "FIELD", "name": "name"}}
            }
          , { "type": "singleton_map"
            , "key": "template-args"
            , "value": {"type": "FIELD", "name": "args"}
            }
          , { "type": "singleton_map"
            , "key": "lua filters"
            , "value": {"type": "var", "name": "lua filters"}
            }
          ]
        }
      }
    }
  }
, "metadata":
  { "doc":
    ["Generate a file with meta data from data provided through context"]
  , "config_vars": ["SOURCE_DATE_EPOCH", "DATE_FORMAT"]
  , "config_doc":
    { "SOURCE_DATE_EPOCH":
      [ "The timestamp to include (in seconds since Jan 1, 1970 00:00 UTC);"
      , "ignored if unset or value is 0."
      ]
    , "DATE_FORMAT":
      ["The format to use for time stamps (defaults to \"%Y-%m-%d %H:%M\")."]
    }
  , "expression":
    { "type": "let*"
    , "bindings":
      [ [ "script"
        , { "type": "join"
          , "separator": "\n"
          , "$1":
            { "type": "++"
            , "$1":
              [ ["echo", "echo ---"]
              , { "type": "if"
                , "cond": {"type": "var", "name": "SOURCE_DATE_EPOCH"}
                , "then":
                  [ { "type": "join_cmd"
                    , "$1":
                      [ "date"
                      , "-d"
                      , { "type": "join"
                        , "$1":
                          [ "@"
                          , { "type": "json_encode"
                            , "$1":
                              {"type": "var", "name": "SOURCE_DATE_EPOCH"}
                            }
                          ]
                        }
                      , { "type": "join"
                        , "$1":
                          [ "+date: \""
                          , { "type": "var"
                            , "name": "DATE_FORMAT"
                            , "default": "%Y-%m-%d %H:%M"
                            }
                          , "\""
                          ]
                        }
                      ]
                    }
                  ]
                }
              , ["echo ---", "echo\n"]
              ]
            }
          }
        ]
      , [ "data"
        , { "type": "ACTION"
          , "cmd": ["sh", "-c", "sh ./generate > metadata.yaml"]
          , "outs": ["metadata.yaml"]
          , "inputs":
            { "type": "singleton_map"
            , "key": "generate"
            , "value":
              {"type": "BLOB", "data": {"type": "var", "name": "script"}}
            }
          }
        ]
      ]
    , "body": {"type": "RESULT", "artifacts": {"type": "var", "name": "data"}}
    }
  }
, "standalone":
  { "doc": ["Create a standalone document from the given inputs"]
  , "target_fields": ["srcs", "template", "data", "meta data files"]
  , "string_fields": ["out", "meta data", "via"]
  , "field_doc":
    { "srcs":
      [ "The files to build the document from, in order."
      , "Honors the order within a [\"files\", \"ordered\"] target."
      ]
    , "data": ["Additional files needed for building (e.g., images)"]
    , "out":
      ["The name of the output file.", "Must not conflict with input files."]
    , "template": ["The template definition to use"]
    , "meta data":
      [ "Additional meta data to be set. Each entry has to have the"
      , "form \"key=value\"."
      ]
    , "meta data files":
      ["Additional meta data files to be taken into account"]
    , "via":
      [ "If a non-empty string is given, first convert all input files to this"
      , "format, if not of this format already."
      , "(entries in this field are concatenated)"
      ]
    }
  , "config_vars": ["env", "TYPESETTING_EXECUTION_PROPERTIES"]
  , "config_doc":
    { "env":
      [ "Any override to the default environment which sets only"
      , "PATH, SOURCE_DATE_EPOCH, and TEXINPUTS"
      ]
    , "TYPESETTING_EXECUTION_PROPERTIES":
      [ "Map of additional remote-execution properties to add for the typesetting"
      , "actions; defaults to the empty map."
      ]
    }
  , "implicit": {"metadata": [["./", ".", "metadata"]]}
  , "imports":
    { "src names": ["./", "../files", "order"]
    , "stage": ["./", "..", "stage_singleton_field"]
    }
  , "expression":
    { "type": "let*"
    , "bindings":
      [ [ "out"
        , { "type": "assert_non_empty"
          , "msg": "A valid output name has to be provided"
          , "$1": {"type": "join", "$1": {"type": "FIELD", "name": "out"}}
          }
        ]
      , [ "env"
        , { "type": "map_union"
          , "$1":
            [ { "type": "singleton_map"
              , "key": "PATH"
              , "value": "/bin:/usr/bin:/usr/local/bin"
              }
            , { "type": "singleton_map"
              , "key": "SOURCE_DATE_EPOCH"
              , "value": "0"
              }
            , {"type": "singleton_map", "key": "TEXINPUTS", "value": "data:"}
            , {"type": "var", "name": "env", "default": {"type": "empty_map"}}
            ]
          }
        ]
      , [ "srcs"
        , { "type": "disjoint_map_union"
          , "msg": "Sources may not conflict"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "srcs"}
            , "body":
              { "type": "map_union"
              , "$1":
                [ {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "x"}}
                , { "type": "DEP_ARTIFACTS"
                  , "dep": {"type": "var", "name": "x"}
                  }
                ]
              }
            }
          }
        ]
      , [ "extra"
        , { "type": "disjoint_map_union"
          , "msg": "Data files may not conflict"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "data"}
            , "body":
              { "type": "map_union"
              , "$1":
                [ {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "x"}}
                , { "type": "DEP_ARTIFACTS"
                  , "dep": {"type": "var", "name": "x"}
                  }
                ]
              }
            }
          }
        ]
      , [ "extra"
        , { "type": "to_subdir"
          , "subdir": "data"
          , "$1": {"type": "var", "name": "extra"}
          }
        ]
      , ["via", {"type": "join", "$1": {"type": "FIELD", "name": "via"}}]
      , [".via", {"type": "join", "$1": [".", {"type": "var", "name": "via"}]}]
      , [ "srcs"
        , { "type": "if"
          , "cond": {"type": "var", "name": "via"}
          , "else": {"type": "var", "name": "srcs"}
          , "then":
            { "type": "disjoint_map_union"
            , "msg": "Converted files must not overlap"
            , "$1":
              { "type": "foreach_map"
              , "range": {"type": "var", "name": "srcs"}
              , "body":
                { "type": "let*"
                , "bindings":
                  [ [ "old"
                    , { "type": "singleton_map"
                      , "key": {"type": "var", "name": "_"}
                      , "value": {"type": "var", "name": "$_"}
                      }
                    ]
                  , [ "new_name"
                    , { "type": "change_ending"
                      , "ending": {"type": "var", "name": ".via"}
                      , "$1": {"type": "var", "name": "_"}
                      }
                    ]
                  ]
                , "body":
                  { "type": "if"
                  , "cond":
                    { "type": "=="
                    , "$1": {"type": "var", "name": "_"}
                    , "$2": {"type": "var", "name": "new_name"}
                    }
                  , "then": {"type": "var", "name": "old"}
                  , "else":
                    { "type": "ACTION"
                    , "inputs":
                      { "type": "map_union"
                      , "$1":
                        [ {"type": "var", "name": "extra"}
                        , {"type": "var", "name": "old"}
                        ]
                      }
                    , "outs": [{"type": "var", "name": "new_name"}]
                    , "env": {"type": "var", "name": "env"}
                    , "cmd":
                      [ "pandoc"
                      , "-o"
                      , {"type": "var", "name": "new_name"}
                      , {"type": "var", "name": "_"}
                      ]
                    , "execution properties":
                      { "type": "var"
                      , "name": "TYPESETTING_EXECUTION_PROPERTIES"
                      , "default": {"type": "empty_map"}
                      }
                    }
                  }
                }
              }
            }
          }
        ]
      , [ "srcs"
        , { "type": "to_subdir"
          , "subdir": "srcs"
          , "$1": {"type": "var", "name": "srcs"}
          }
        ]
      , [ "data"
        , { "type": "disjoint_map_union"
          , "msg": "Template files may not conflict"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "template"}
            , "body":
              { "type": "map_union"
              , "$1":
                [ {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "x"}}
                , { "type": "DEP_ARTIFACTS"
                  , "dep": {"type": "var", "name": "x"}
                  }
                ]
              }
            }
          }
        ]
      , [ "data"
        , { "type": "to_subdir"
          , "subdir": "data"
          , "$1":
            { "type": "disjoint_map_union"
            , "msg": "Template may not contain a \"data\" directory"
            , "$1":
              [ {"type": "var", "name": "data"}
              , {"type": "var", "name": "extra"}
              ]
            }
          }
        ]
      , [ "lua filters"
        , { "type": "disjoint_map_union"
          , "msg": "Lua filters may not conflict"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "template"}
            , "body":
              { "type": "DEP_PROVIDES"
              , "provider": "lua filters"
              , "dep": {"type": "var", "name": "x"}
              }
            }
          }
        ]
      , [ "lua filters"
        , { "type": "to_subdir"
          , "subdir": "lua"
          , "$1": {"type": "var", "name": "lua filters"}
          }
        ]
      , [ "template-name"
        , { "type": "join"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "template"}
            , "body":
              { "type": "DEP_PROVIDES"
              , "dep": {"type": "var", "name": "x"}
              , "provider": "template-name"
              , "default": "default"
              }
            }
          }
        ]
      , [ "template-args"
        , { "type": "++"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "template"}
            , "body":
              { "type": "DEP_PROVIDES"
              , "dep": {"type": "var", "name": "x"}
              , "provider": "template-args"
              }
            }
          }
        ]
      , [ "_"
        , { "type": "if"
          , "cond":
            { "type": "lookup"
            , "map": {"type": "var", "name": "srcs"}
            , "key": {"type": "var", "name": "out"}
            }
          , "then":
            { "type": "fail"
            , "msg":
              [ "Output must be disjoint from inputs."
              , "Output file name is"
              , {"type": "var", "name": "out"}
              , "input files are"
              , {"type": "keys", "$1": {"type": "var", "name": "srcs"}}
              ]
            }
          }
        ]
      , ["src names", {"type": "CALL_EXPRESSION", "name": "src names"}]
      , [ "src names"
        , { "type": "if"
          , "cond": {"type": "var", "name": "via"}
          , "else": {"type": "var", "name": "src names"}
          , "then":
            { "type": "foreach"
            , "range": {"type": "var", "name":"src names"}
            , "body":
              { "type": "change_ending"
              , "ending": {"type": "var", "name": ".via"}
              , "$1": {"type": "var", "name": "_"}
              }
            }
          }
        ]
      , [ "src names"
        , { "type": "foreach"
          , "var": "name"
          , "range": {"type": "var", "name": "src names"}
          , "body":
            {"type": "join", "$1": ["srcs/", {"type": "var", "name": "name"}]}
          }
        ]
      , [ "meta data args"
        , { "type": "++"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range": {"type": "FIELD", "name": "meta data"}
            , "body": ["-M", {"type": "var", "name": "x"}]
            }
          }
        ]
      , [ "filter args"
        , { "type": "++"
          , "$1":
            { "type": "foreach"
            , "var": "x"
            , "range":
              {"type": "keys", "$1": {"type": "var", "name": "lua filters"}}
            , "body": ["--lua-filter", {"type": "var", "name": "x"}]
            }
          }
        ]
      , [ "metadata"
        , { "type": "let*"
          , "bindings":
            [["fieldname", "metadata"], ["location", "metadata.yaml"]]
          , "body": {"type": "CALL_EXPRESSION", "name": "stage"}
          }
        ]
      , [ "extra metadata files"
        , { "type": "++"
          , "$1":
            { "type": "foreach"
            , "range": {"type": "FIELD", "name": "meta data files"}
            , "body":
              { "type": "values"
              , "$1":
                {"type": "DEP_ARTIFACTS", "dep": {"type": "var", "name": "_"}}
              }
            }
          }
        ]
      , [ "staged extra metadata"
        , { "type": "map_union"
          , "$1":
            { "type": "foreach_map"
            , "range":
              { "type": "enumerate"
              , "$1": {"type": "var", "name": "extra metadata files"}
              }
            , "body":
              { "type": "singleton_map"
              , "key":
                { "type": "join"
                , "$1": ["metadta", {"type": "var", "name": "_"}, ".yaml"]
                }
              , "value": {"type": "var", "name": "$_"}
              }
            }
          }
        ]
      , [ "generated"
        , { "type": "ACTION"
          , "inputs":
            { "type": "map_union"
            , "$1":
              [ {"type": "var", "name": "srcs"}
              , {"type": "var", "name": "data"}
              , {"type": "var", "name": "lua filters"}
              , {"type": "var", "name": "metadata"}
              , {"type": "var", "name": "staged extra metadata"}
              ]
            }
          , "outs": [{"type": "var", "name": "out"}]
          , "env": {"type": "var", "name": "env"}
          , "cmd":
            { "type": "++"
            , "$1":
              [ [ "pandoc"
                , "--data-dir=./data"
                , "--resource-path=./data"
                , "-o"
                , {"type": "var", "name": "out"}
                , "-s"
                , "-N"
                ]
              , { "type": "if"
                , "cond": {"type": "var", "name": "template-name"}
                , "then":
                  ["--template", {"type": "var", "name": "template-name"}]
                }
              , ["--metadata-file", "metadata.yaml"]
              , { "type": "++"
                , "$1":
                  { "type": "foreach"
                  , "range":
                    { "type": "keys"
                    , "$1": {"type": "var", "name": "staged extra metadata"}
                    }
                  , "body": ["--metadata-file", {"type": "var", "name": "_"}]
                  }
                }
              , {"type": "var", "name": "template-args"}
              , {"type": "var", "name": "filter args"}
              , {"type": "var", "name": "meta data args"}
              , {"type": "var", "name": "src names"}
              ]
            }
          , "execution properties":
            { "type": "var"
            , "name": "TYPESETTING_EXECUTION_PROPERTIES"
            , "default": {"type": "empty_map"}
            }
          }
        ]
      ]
    , "body":
      {"type": "RESULT", "artifacts": {"type": "var", "name": "generated"}}
    }
  }
}