proc arg(self: Asdlkeyword): AsdlIdentifier {....raises: [], tags: [], forbids: [].}

proc ast(input, fileName: string): Asdlmodl {....raises: [SyntaxError],
    tags: [RootEffect, WriteIOEffect], forbids: [].}

proc ast(root: ParseNode): Asdlmodl {....raises: [SyntaxError:ObjectType],
                                      tags: [RootEffect], forbids: [].}

proc newIdentifier(value: string): AsdlIdentifier {....raises: [],
    tags: [RootEffect], forbids: [].}

proc value(self: Asdlkeyword): Asdlexpr {....raises: [], tags: [], forbids: [].}

template raiseSyntaxError(msg: string; astNode: untyped)