Allow specification of semantic predicates.

[bison.git] / src / parse-gram.y

diff --git a/src/parse-gram.y b/src/parse-gram.y
index 453c35f84a944f2fe09e9dd3340ea07c60925e71..d588dfa8ab0f2ba015414a37cf7f8059e058d6cd 100644 (file)
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -1,7 +1,7 @@
 %{/* Bison Grammar Parser                             -*- C -*-
 
-   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software
-   Foundation, Inc.
+   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -118,7 +118,6 @@ static char const *char_name (char);
 %token PERCENT_DPREC         "%dprec"
 %token PERCENT_MERGE         "%merge"
 
-
 /*----------------------.
 | Global Declarations.  |
 `----------------------*/
@@ -151,6 +150,8 @@ static char const *char_name (char);
 ;
 
 %token BRACED_CODE     "{...}"
+%token BRACED_PREDICATE "%?{...}"
+%token BRACKETED_ID    "[identifier]"
 %token CHAR            "char"
 %token EPILOGUE        "epilogue"
 %token EQUAL           "="
@@ -163,7 +164,6 @@ static char const *char_name (char);
 %token TAG             "<tag>"
 %token TAG_ANY         "<*>"
 %token TAG_NONE        "<>"
-%token BRACKETED_ID    "[identifier]"
 
 %type <character> CHAR
 %printer { fputs (char_name ($$), stderr); } CHAR
@@ -171,28 +171,29 @@ static char const *char_name (char);
 /* braceless is not to be used for rule or symbol actions, as it
    calls code_props_plain_init.  */
 %type <chars> STRING "%{...%}" EPILOGUE braceless content.opt
-%type <code> "{...}"
+%type <code> "{...}" "%?{...}"
 %printer { fputs (quotearg_style (c_quoting_style, $$), stderr); }
         STRING
 %printer { fprintf (stderr, "{\n%s\n}", $$); }
         braceless content.opt "{...}" "%{...%}" EPILOGUE
 
-%type <uniqstr> TAG ID ID_COLON BRACKETED_ID PERCENT_FLAG variable
-%type <named_ref> named_ref.opt
-%printer { fputs ($$, stderr); } ID variable
+%type <uniqstr> BRACKETED_ID ID ID_COLON PERCENT_FLAG TAG variable
+%printer { fputs ($$, stderr); } <uniqstr>
+%printer { fprintf (stderr, "[%s]", $$); } BRACKETED_ID
 %printer { fprintf (stderr, "%s:", $$); } ID_COLON
 %printer { fprintf (stderr, "%%%s", $$); } PERCENT_FLAG
 %printer { fprintf (stderr, "<%s>", $$); } TAG
 
 %type <integer> INT
-%printer { fprintf (stderr, "%d", $$); } INT
+%printer { fprintf (stderr, "%d", $$); } <integer>
 
-%type <symbol> id id_colon symbol symbol.prec string_as_id
-%printer { fprintf (stderr, "%s", $$->tag); } id symbol string_as_id
+%type <symbol> id id_colon string_as_id symbol symbol.prec
+%printer { fprintf (stderr, "%s", $$->tag); } <symbol>
 %printer { fprintf (stderr, "%s:", $$->tag); } id_colon
 
 %type <assoc> precedence_declarator
 %type <list>  symbols.1 symbols.prec generic_symlist generic_symlist_item
+%type <named_ref> named_ref.opt
 
 /*---------.
 | %param.  |
@@ -236,6 +237,7 @@ static char const *char_name (char);
       CASE(parse, parse-param);
       CASE(both,  param);
 #undef CASE
+      case param_none: aver (false); break;
     }
 } <param>;
 
@@ -584,7 +586,9 @@ rhs:
 | rhs symbol named_ref.opt
     { grammar_current_rule_symbol_append ($2, @2, $3); }
 | rhs "{...}" named_ref.opt
-    { grammar_current_rule_action_append ($2, @2, $3); }
+    { grammar_current_rule_action_append ($2, @2, $3, false); }
+| rhs "%?{...}" 
+    { grammar_current_rule_action_append ($2, @2, NULL, true); }
 | rhs "%prec" symbol
     { grammar_current_rule_prec_set ($3, @3); }
 | rhs "%dprec" INT
@@ -599,7 +603,6 @@ named_ref.opt:
   BRACKETED_ID   { $$ = named_ref_new($1, @1); }
 ;
 
-
 /*---------------------------.
 | variable and content.opt.  |
 `---------------------------*/
@@ -727,23 +730,25 @@ add_param (param_type type, char *decl, location loc)
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "_"
     "0123456789";
+
   char const *name_start = NULL;
-  char *p;
-
-  /* Stop on last actual character.  */
-  for (p = decl; p[1]; p++)
-    if ((p == decl
-        || ! memchr (alphanum, p[-1], sizeof alphanum))
-       && memchr (alphanum, p[0], sizeof alphanum - 10))
-      name_start = p;
-
-  /* Strip the surrounding '{' and '}', and any blanks just inside
-     the braces.  */
-  while (*--p == ' ' || *p == '\t')
-    continue;
-  p[1] = '\0';
-  while (*++decl == ' ' || *decl == '\t')
-    continue;
+  {
+    char *p;
+    /* Stop on last actual character.  */
+    for (p = decl; p[1]; p++)
+      if ((p == decl
+           || ! memchr (alphanum, p[-1], sizeof alphanum))
+          && memchr (alphanum, p[0], sizeof alphanum - 10))
+        name_start = p;
+
+    /* Strip the surrounding '{' and '}', and any blanks just inside
+       the braces.  */
+    while (*--p == ' ' || *p == '\t')
+      continue;
+    p[1] = '\0';
+    while (*++decl == ' ' || *decl == '\t')
+      continue;
+  }
 
   if (! name_start)
     complain_at (loc, _("missing identifier in parameter declaration"));