grammar: split %union to group together related aspects

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

diff --git a/src/parse-gram.y b/src/parse-gram.y
index 8a2a04ea32e2e27551caf7c384b299f6f459736d..50b90cf0b732c5279b11a3d48d4f9663457395d0 100644 (file)
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -40,17 +40,13 @@
 static YYLTYPE lloc_default (YYLTYPE const *, int);
 
 #define YY_LOCATION_PRINT(File, Loc) \
-          location_print (File, Loc)
+          location_print (Loc, File)
 
 static void version_check (location const *loc, char const *version);
 
-/* Request detailed syntax error messages, and pass them to GRAM_ERROR.
-   FIXME: depends on the undocumented availability of YYLLOC.  */
-#undef  yyerror
-#define yyerror(Msg) \
-        gram_error (&yylloc, Msg)
 static void gram_error (location const *, char const *);
 
+/* A string that describes a char (e.g., 'a' -> "'a'").  */
 static char const *char_name (char);
 %}
 
@@ -68,7 +64,7 @@ static char const *char_name (char);
    */
   static
   void
-  current_lhs(symbol *sym, location loc, named_ref *ref)
+  current_lhs (symbol *sym, location loc, named_ref *ref)
   {
     current_lhs_symbol = sym;
     current_lhs_location = loc;
@@ -88,7 +84,7 @@ static char const *char_name (char);
 }
 
 %define api.prefix "gram_"
-%define api.pure
+%define api.pure full
 %define locations
 %define parse.error verbose
 %define parse.lac full
@@ -105,23 +101,9 @@ static char const *char_name (char);
   boundary_set (&@$.end, current_file, 1, 1);
 }
 
-%union
-{
-  assoc assoc;
-  char *code;
-  char const *chars;
-  int integer;
-  named_ref *named_ref;
-  symbol *symbol;
-  symbol_list *list;
-  uniqstr uniqstr;
-  unsigned char character;
-};
-
 /* Define the tokens together with their human representation.  */
 %token GRAM_EOF 0 "end of file"
 %token STRING     "string"
-%token INT        "integer"
 
 %token PERCENT_TOKEN       "%token"
 %token PERCENT_NTERM       "%nterm"
@@ -186,11 +168,17 @@ static char const *char_name (char);
 %token TAG_ANY         "<*>"
 %token TAG_NONE        "<>"
 
+%union {unsigned char character;}
 %type <character> CHAR
 %printer { fputs (char_name ($$), yyo); } CHAR
 
 /* braceless is not to be used for rule or symbol actions, as it
    calls code_props_plain_init.  */
+%union
+{
+  char *code;
+  char const *chars;
+};
 %type <chars> STRING "%{...%}" EPILOGUE braceless content.opt
 %type <code> "{...}" "%?{...}"
 %printer { fputs (quotearg_style (c_quoting_style, $$), yyo); }
@@ -198,6 +186,7 @@ static char const *char_name (char);
 %printer { fprintf (yyo, "{\n%s\n}", $$); }
          braceless content.opt "{...}" "%{...%}" EPILOGUE
 
+%union {uniqstr uniqstr;}
 %type <uniqstr> BRACKETED_ID ID ID_COLON PERCENT_FLAG TAG tag variable
 %printer { fputs ($$, yyo); } <uniqstr>
 %printer { fprintf (yyo, "[%s]", $$); } BRACKETED_ID
@@ -205,15 +194,22 @@ static char const *char_name (char);
 %printer { fprintf (yyo, "%%%s", $$); } PERCENT_FLAG
 %printer { fprintf (yyo, "<%s>", $$); } TAG tag
 
-%type <integer> INT
+%union {int integer;};
+%token <integer> INT "integer"
 %printer { fprintf (yyo, "%d", $$); } <integer>
 
+%union {symbol *symbol;}
 %type <symbol> id id_colon string_as_id symbol symbol.prec
 %printer { fprintf (yyo, "%s", $$->tag); } <symbol>
 %printer { fprintf (yyo, "%s:", $$->tag); } id_colon
 
+%union {assoc assoc;};
 %type <assoc> precedence_declarator
+
+%union {symbol_list *list;}
 %type <list>  symbols.1 symbols.prec generic_symlist generic_symlist_item
+
+%union {named_ref *named_ref;}
 %type <named_ref> named_ref.opt
 
 /*---------.
@@ -254,9 +250,9 @@ static char const *char_name (char);
     {
 #define CASE(In, Out)                                           \
       case param_ ## In: fputs ("%" #Out, stderr); break
-      CASE(lex,   lex-param);
-      CASE(parse, parse-param);
-      CASE(both,  param);
+      CASE (lex,   lex-param);
+      CASE (parse, parse-param);
+      CASE (both,  param);
 #undef CASE
       case param_none: aver (false); break;
     }
@@ -278,7 +274,7 @@ input:
         `------------------------------------*/
 
 prologue_declarations:
-  /* Nothing */
+  %empty
 | prologue_declarations prologue_declaration
 ;
 
@@ -434,15 +430,15 @@ code_props_type:
 %token PERCENT_UNION "%union";
 
 union_name:
-  /* Nothing. */ {}
-| ID             { muscle_code_grow ("union_name", $1, @1); }
+  %empty {}
+| ID     { muscle_code_grow ("union_name", $1, @1); }
 ;
 
 grammar_declaration:
   "%union" union_name braceless
     {
       union_seen = true;
-      muscle_code_grow ("stype", $3, @3);
+      muscle_code_grow ("union_members", $3, @3);
       code_scanner_last_string_free ();
     }
 ;
@@ -494,8 +490,8 @@ precedence_declarator:
 ;
 
 tag.opt:
-  /* Nothing. */ { current_type = NULL; }
-| TAG            { current_type = $1; tag_seen = true; }
+  %empty { current_type = NULL; }
+| TAG    { current_type = $1; tag_seen = true; }
 ;
 
 /* Just like symbols.1 but accept INT for the sake of POSIX.  */
@@ -507,8 +503,17 @@ symbols.prec:
 ;
 
 symbol.prec:
-  symbol     { $$ = $1; }
-| symbol INT { $$ = $1; symbol_user_token_number_set ($1, $2, @2); }
+  symbol
+    {
+      $$ = $1;
+      symbol_class_set ($1, token_sym, @1, false);
+    }
+| symbol INT
+    {
+      $$ = $1;
+      symbol_user_token_number_set ($1, $2, @2);
+      symbol_class_set ($1, token_sym, @1, false);
+    }
 ;
 
 /* One or more symbols to be %typed. */
@@ -609,8 +614,9 @@ rhses.1:
 | rhses.1 ";"
 ;
 
+%token PERCENT_EMPTY "%empty";
 rhs:
-  /* Nothing.  */
+  %empty
     { grammar_current_rule_begin (current_lhs_symbol, current_lhs_location,
                                   current_lhs_named_ref); }
 | rhs symbol named_ref.opt
@@ -619,6 +625,8 @@ rhs:
     { grammar_current_rule_action_append ($2, @2, $3, false); }
 | rhs "%?{...}"
     { grammar_current_rule_action_append ($2, @2, NULL, true); }
+| rhs "%empty"
+    { grammar_current_rule_empty_set (@2); }
 | rhs "%prec" symbol
     { grammar_current_rule_prec_set ($3, @3); }
 | rhs "%dprec" INT
@@ -628,9 +636,8 @@ rhs:
 ;
 
 named_ref.opt:
-  /* Nothing. */ { $$ = 0; }
-|
-  BRACKETED_ID   { $$ = named_ref_new($1, @1); }
+  %empty         { $$ = 0; }
+| BRACKETED_ID   { $$ = named_ref_new($1, @1); }
 ;
 
 /*---------------------------.
@@ -638,7 +645,7 @@ named_ref.opt:
 `---------------------------*/
 
 /* The STRING form of variable is deprecated and is not M4-friendly.
-   For example, M4 fails for `%define "[" "value"'.  */
+   For example, M4 fails for '%define "[" "value"'.  */
 variable:
   ID
 | STRING { $$ = uniqstr_new ($1); }
@@ -646,9 +653,9 @@ variable:
 
 /* Some content or empty by default. */
 content.opt:
-  /* Nothing. */   { $$ = ""; }
-| ID { $$ = $1; }
-| STRING
+  %empty    { $$ = ""; }
+| ID        { $$ = $1; }
+| STRING    { $$ = $1; }
 ;
 
 
@@ -707,7 +714,7 @@ string_as_id:
 ;
 
 epilogue.opt:
-  /* Nothing.  */
+  %empty
 | "%%" EPILOGUE
     {
       code_props plain_code;