Move the extra_token mechanism out of the lexer proper

Calling lex->pop_extra_token explicitly in the parser's yylex function
makes things considerably more robust.  It also allows pushing and
popping the EOF condition, necessary for backing up right at the end
of a file, like with ##{ \relative { c d e f } #} where the music
expression is checked against being a pitch, and then is backed up.

diff --git a/lily/include/lily-lexer.hh b/lily/include/lily-lexer.hh
index 4bc4cbe887403eb685cecf84442c2f741ad0f7f7..ce428603cb2dce8cd24efc69ace8751194612ff3 100644 (file)
--- a/lily/include/lily-lexer.hh
+++ b/lily/include/lily-lexer.hh
@@ -49,7 +49,6 @@ private:
   Keyword_table *keytable_;
   SCM scopes_;
   SCM start_module_;
-  int hidden_state_;
   Input override_input_;
   SCM eval_scm (SCM, char extra_token = 0);
 public:
@@ -95,6 +94,7 @@ public:
   SCM lookup_identifier (const string &s);
   SCM lookup_identifier_symbol (SCM s);
   void push_extra_token (int token_type, SCM scm = SCM_UNSPECIFIED);
+  int pop_extra_token ();
   void push_chord_state (SCM alist);
   void push_figuredbass_state ();
   void push_lyric_state ();

diff --git a/lily/lexer.ll b/lily/lexer.ll
index 71473faa30fc9d4375de779494b183cff29416fb..a360de48c137515ad5fd98251921e1e8caf983be 100644 (file)
--- a/lily/lexer.ll
+++ b/lily/lexer.ll
@@ -123,7 +123,6 @@ SCM (* scm_parse_error_handler) (void *);
 %option never-interactive 
 %option warn
 
-%x extratoken
 %x chords
 %x figures
 %x incl
@@ -186,36 +185,6 @@ BOM_UTF8   \357\273\277
        // swallow and ignore carriage returns
 }
 
-<extratoken>{ANY_CHAR} {
-  /* Generate a token without swallowing anything */
-
-  /* First unswallow the eaten character */
-  add_lexed_char (-YYLeng ());
-  yyless (0);
-
-  /* produce requested token */
-  int type = scm_to_int (scm_caar (extra_tokens_));
-  yylval = scm_cdar (extra_tokens_);
-  extra_tokens_ = scm_cdr (extra_tokens_);
-  if (scm_is_null (extra_tokens_))
-    yy_pop_state ();
-
-  return type;
-}
-
-<extratoken><<EOF>>    {
-  /* Generate a token without swallowing anything */
-
-  /* produce requested token */
-  int type = scm_to_int (scm_caar (extra_tokens_));
-  yylval = scm_cdar (extra_tokens_);
-  extra_tokens_ = scm_cdr (extra_tokens_);
-  if (scm_is_null (extra_tokens_))
-    yy_pop_state ();
-
-  return type;
-}
-
    /* Use the trailing context feature. Otherwise, the BOM will not be
       found if the file starts with an identifier definition. */
 <INITIAL,chords,lyrics,figures,notes>{BOM_UTF8}/.* {
@@ -848,15 +817,22 @@ BOM_UTF8  \357\273\277
 void
 Lily_lexer::push_extra_token (int token_type, SCM scm)
 {
-       if (scm_is_null (extra_tokens_))
-       {
-               if (YY_START != extratoken)
-                       hidden_state_ = YY_START;
-               yy_push_state (extratoken);
-       }
        extra_tokens_ = scm_acons (scm_from_int (token_type), scm, extra_tokens_);
 }
 
+int
+Lily_lexer::pop_extra_token ()
+{
+       if (scm_is_null (extra_tokens_))
+               return -1;
+
+  /* produce requested token */
+       int type = scm_to_int (scm_caar (extra_tokens_));
+       yylval = scm_cdar (extra_tokens_);
+       extra_tokens_ = scm_cdr (extra_tokens_);
+       return type;
+}
+
 void
 Lily_lexer::push_chord_state (SCM alist)
 {
@@ -895,32 +871,17 @@ Lily_lexer::push_markup_state ()
 void
 Lily_lexer::push_note_state (SCM alist)
 {
-       bool extra = (YYSTATE == extratoken);
-
        SCM p = scm_assq (alist, pitchname_tab_stack_);
 
-       if (extra)
-               yy_pop_state ();
-
        if (scm_is_false (p))
                p = scm_cons (alist, alist_to_hashq (alist));
        pitchname_tab_stack_ = scm_cons (p, pitchname_tab_stack_);
        yy_push_state (notes);
-
-       if (extra) {
-               hidden_state_ = YYSTATE;
-               yy_push_state (extratoken);
-       }
 }
 
 void
 Lily_lexer::pop_state ()
 {
-       bool extra = (YYSTATE == extratoken);
-
-       if (extra)
-               yy_pop_state ();
-
        if (YYSTATE == notes || YYSTATE == chords)
                pitchname_tab_stack_ = scm_cdr (pitchname_tab_stack_);
 
@@ -928,10 +889,6 @@ Lily_lexer::pop_state ()
        if (YYSTATE != maininput)
                yy_pop_state ();
 
-       if (extra) {
-               hidden_state_ = YYSTATE;
-               yy_push_state (extratoken);
-       }
 }
 
 int
@@ -1075,10 +1032,7 @@ Lily_lexer::scan_bare_word (const string &str)
 int
 Lily_lexer::get_state () const
 {
-       if (YY_START == extratoken)
-               return hidden_state_;
-       else
-               return YY_START;
+       return YY_START;
 }
 
 bool

diff --git a/lily/parser.yy b/lily/parser.yy
index 7891a3b22d39d6e682eaa3cdc13c19ccba0f5797..385c906724bd9810bdd90dac87d5c8a82b290c45 100644 (file)
--- a/lily/parser.yy
+++ b/lily/parser.yy
@@ -3970,6 +3970,9 @@ yylex (YYSTYPE *s, YYLTYPE *loc, Lily_parser *parser)
 
        lex->lexval_ = s;
        lex->lexloc_ = loc;
+       int tok = lex->pop_extra_token ();
+       if (tok >= 0)
+               return tok;
        lex->prepare_for_next_token ();
        return lex->yylex ();
 }