pub fn expr_node<'slice, 'src: 'slice>(
node: Token,
parser: impl Parser<Input<'slice, 'src, LustreLang>, Children<LustreLang, ParserError>, ParserError>,
) -> impl FnMut(Input<'slice, 'src, LustreLang>) -> IResult<'slice, 'src, LustreLang, ParserError, ParserError>