{ "generated files":
  { "string_fields": ["width"]
  , "expression":
    { "type": "RESULT"
    , "artifacts":
      { "type": "map_union"
      , "$1":
        { "type": "foreach"
        , "var": "n"
        , "range":
          { "type": "range"
          , "$1": {"type": "join", "$1": {"type": "FIELD", "name": "width"}}
          }
        , "body":
          { "type": "let*"
          , "bindings":
            [ [ "src"
              , { "type": "join"
                , "$1":
                  [ "#include <stdio.h>\n"
                  , "int main(int argc, char **argv) {\n"
                  , "  printf(\"Hello from generated program #%s!\", \""
                  , {"type": "var", "name": "n"}
                  , "\");\n"
                  , "  return 0;\n"
                  , "}\n"
                  ]
                }
              ]
            , [ "src file"
              , { "type": "singleton_map"
                , "key": "hello.c"
                , "value":
                  {"type": "BLOB", "data": {"type": "var", "name": "src"}}
                }
              ]
            , [ "hello"
              , { "type": "ACTION"
                , "inputs": {"type": "var", "name": "src file"}
                , "outs": ["hello"]
                , "cmd": ["cc", "-o", "hello", "hello.c"]
                , "env":
                  { "type": "singleton_map"
                  , "key": "PATH"
                  , "value": "/bin:/sbin:/usr/bin:/usr/sbin"
                  }
                }
              ]
            , [ "out"
              , { "type": "ACTION"
                , "inputs": {"type": "var", "name": "hello"}
                , "outs":
                  [ { "type": "join"
                    , "$1": ["out-", {"type": "var", "name": "n"}, ".txt"]
                    }
                  ]
                , "cmd":
                  [ "/bin/sh"
                  , "-c"
                  , { "type": "join"
                    , "$1":
                      ["./hello > out-", {"type": "var", "name": "n"}, ".txt"]
                    }
                  ]
                }
              ]
            ]
          , "body": {"type": "var", "name": "out"}
          }
        }
      }
    }
  }
}