-@item @code{parser}
-@tab needs to be literally @code{parser} in order to give LilyPond code
-blocks (@code{#@{}@dots{}@code{#@}}) access to the parser.
-
-@item @code{location}
-@tab needs to be literally @code{location} in order to provide access
-to the input location object, which is used to provide error messages
-with file names and line numbers.
-