From 187f5d255574bb4cfe744cbccf10aec821d6ae6e Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Wed, 11 Aug 2010 14:15:55 -0500
Subject: [PATCH] don't allow ly:parser-parse-string to continue unless the
 parser is fresh

---
 lily/include/lily-lexer.hh | 1 +
 lily/lily-lexer.cc         | 6 ++++++
 lily/lily-parser-scheme.cc | 6 +++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/lily/include/lily-lexer.hh b/lily/include/lily-lexer.hh
index f2491864ea..a7d697d482 100644
--- a/lily/include/lily-lexer.hh
+++ b/lily/include/lily-lexer.hh
@@ -116,6 +116,7 @@ public:
   bool is_chord_state () const;
   bool is_lyric_state () const;
   bool is_figure_state () const;
+  bool is_clean () const;
 };
 
 #endif /* MY_LILY_LEXER_HH */
diff --git a/lily/lily-lexer.cc b/lily/lily-lexer.cc
index 5a34d60bbe..3b9a3882b1 100644
--- a/lily/lily-lexer.cc
+++ b/lily/lily-lexer.cc
@@ -391,3 +391,9 @@ Lily_lexer::print_smob (SCM s, SCM port, scm_print_state*)
   scm_puts (" >", port);
   return 1;
 }
+
+bool
+Lily_lexer::is_clean () const
+{
+  return include_stack_.empty ();
+}
diff --git a/lily/lily-parser-scheme.cc b/lily/lily-parser-scheme.cc
index 2b968b46c0..2f9a910ccf 100644
--- a/lily/lily-parser-scheme.cc
+++ b/lily/lily-parser-scheme.cc
@@ -200,7 +200,11 @@ LY_DEFINE (ly_parser_parse_string, "ly:parser-parse-string",
   Lily_parser *parser = unsmob_lily_parser (parser_smob);
   LY_ASSERT_TYPE (scm_is_string, ly_code, 2);
 
-  parser->parse_string (ly_scm2string (ly_code));
+  if (!parser->lexer_->is_clean ())
+    parser->parser_error (_ ("ly:parser-parse-string is only valid with a new parser."
+			     "  Use ly:parser-include-string instead."));
+  else
+    parser->parse_string (ly_scm2string (ly_code));
 
   return SCM_UNSPECIFIED;
 }
-- 
2.39.5