void
pop_paper (Lily_parser *parser)
{
- parser->lexer_->set_identifier (ly_symbol2scm ("$papers"),
- scm_cdr (parser->lexer_->lookup_identifier ("$papers")));
+ if (! scm_is_null (parser->lexer_->lookup_identifier ("$papers")))
+ parser->lexer_->set_identifier (ly_symbol2scm ("$papers"),
+ scm_cdr (parser->lexer_->lookup_identifier ("$papers")));
}
/* Change the paper on top of $papers stack */