* src/symtab.h (SALIAS, SUNDEF): Rename as...

(USER_NUMBER_ALIAS, USER_NUMBER_UNDEFINED): these.
Adjust dependencies.
* src/output.c (token_definitions_output): Be sure not to output a
`#define 'a'' when fed with `%token 'a' "a"'.
* tests/regression.at (Token definitions): New.

ChangeLog

@@ -1,3 +1,12 @@
+2002-05-04  Akim Demaille  <akim@epita.fr>
+
+	* src/symtab.h (SALIAS, SUNDEF): Rename as...
+	(USER_NUMBER_ALIAS, USER_NUMBER_UNDEFINED): these.
+	Adjust dependencies.
+	* src/output.c (token_definitions_output): Be sure not to output a
+	`#define 'a'' when fed with `%token 'a' "a"'.
+	* tests/regression.at (Token definitions): New.
+
 2002-05-03  Paul Eggert  <eggert@twinsun.com>
 
 	* data/bison.simple (b4_token_defines): Also define YYTOKENTYPE

NEWS

@@ -64,6 +64,9 @@ Changes in version 1.49b:
 * New tranlations
   Croatian, thanks to Denis Lackovic.
 
+* Token definitions
+  When fed with `%token 'a' "A"', Bison used to output `#define 'a' 65'.
+
 
 Changes in version 1.35, 2002-03-25:
 

TODO

@@ -277,38 +277,6 @@ Rewrite the reader in Flex/Bison.  There will be delicate parts, in
 particular, expect the scanner to be hard to write.  Many interesting
 features cannot be implemented without such a new reader.
 
-* Problems with aliases
-From: "Baum, Nathan I" <s0009525@chelt.ac.uk>
-Subject: Token Alias Bug
-To: "'bug-bison@gnu.org'" <bug-bison@gnu.org>
-
-I've noticed a bug in bison. Sadly, our eternally wise sysadmins won't let
-us use CVS, so I can't find out if it's been fixed already...
-
-Basically, I made a program (in flex) that went through a .y file looking
-for "..."-tokens, and then outputed a %token
-line for it. For single-character ""-tokens, I reasoned, I could just use
-[%token 'A' "A"]. However, this causes Bison to output a [#define 'A' 65],
-which cppp chokes on, not unreasonably. (And even if cppp didn't choke, I
-obviously wouldn't want (char)'A' to be replaced with (int)65 throughout my
-code.
-
-Bison normally forgoes outputing a #define for a character token. However,
-it always outputs an aliased token -- even if the token is an alias for a
-character token. We don't want that. The problem is in /output.c/, as I
-recall. When it outputs the token definitions, it checks for a character
-token, and then checks for an alias token. If the character token check is
-placed after the alias check, then it works correctly.
-
-Alias tokens seem to be something of a kludge. What about an [%alias "..."]
-command...
-
-	%alias T_IF "IF"
-
-Hmm. I can't help thinking... What about a --generate-lex option that
-creates an .l file for the alias tokens used... (Or an option to make a
-gperf file, etc...)
-
 * Presentation of the report file
 From: "Baum, Nathan I" <s0009525@chelt.ac.uk>
 Subject: Token Alias Bug

src/lex.c

@@ -368,7 +368,7 @@ lex (void)
 	  {
 	    symval->number = ntokens++;
 	    symval->class = token_sym;
-	    if (symval->user_token_number == SUNDEF)
+	    if (symval->user_token_number == USER_NUMBER_UNDEFINED)
 	      symval->user_token_number = code;
 	  }
 	return tok_identifier;

src/output.c

@@ -582,21 +582,25 @@ token_definitions_output (FILE *out)
       symbol_t *symbol = symbols[i];
       int number = symbol->user_token_number;
 
-      if (number == SALIAS)
+      /* At this stage, if there are literal aliases, they are part of
-	continue;
+	 SYMBOLS, so we should not find symbols which are the aliases
+	 here.  */
+      assert (number != USER_NUMBER_ALIAS);
+
       /* Skip error token.  */
       if (symbol == errtoken)
 	continue;
-      if (symbol->tag[0] == '\'')
+
-	continue;               /* skip literal character */
+      /* If this string has an alias, then it is necessarily the alias
-      if (symbol->tag[0] == '\"')
+	 which is to be output.  */
-	{
-	  /* use literal string only if given a symbol with an alias */
       if (symbol->alias)
 	symbol = symbol->alias;
-	  else
+
+      /* Don't output literal chars or strings (when defined only as a
+	 string).  Note that must be done after the alias resolution:
+	 think about `%token 'f' "f"'.  */
+      if (symbol->tag[0] == '\'' || symbol->tag[0] == '\"')
 	continue;
-	}
 
       /* Don't #define nonliteral tokens whose names contain periods
 	 or '$' (as does the default value of the EOF token).  */
@@ -605,6 +609,7 @@ token_definitions_output (FILE *out)
 
       fprintf (out, "%s[[[%s]], [%d]]",
 	       first ? "" : ",\n", symbol->tag, number);
+
       first = 0;
     }
 }

src/reader.c

@@ -126,7 +126,7 @@ symbol_make_alias (symbol_t *symbol, char *typename)
       symval->class = token_sym;
       symval->type_name = typename;
       symval->user_token_number = symbol->user_token_number;
-      symbol->user_token_number = SALIAS;
+      symbol->user_token_number = USER_NUMBER_ALIAS;
       symval->alias = symbol;
       symbol->alias = symval;
       /* symbol and symval combined are only one symbol */
@@ -149,7 +149,7 @@ static bool
 symbol_check_alias_consistence (symbol_t *this)
 {
   /* Check only those who _are_ the aliases. */
-  if (this->alias && this->user_token_number == SALIAS)
+  if (this->alias && this->user_token_number == USER_NUMBER_ALIAS)
     {
       if (this->prec != this->alias->prec)
 	{
@@ -204,8 +204,8 @@ symbol_pack (symbol_t *this)
 	      this->number = this->alias->number;
 	    }
 	}
-      /* Do not do processing below for SALIASs.  */
+      /* Do not do processing below for USER_NUMBER_ALIASs.  */
-      if (this->user_token_number == SALIAS)
+      if (this->user_token_number == USER_NUMBER_ALIAS)
 	return TRUE;
     }
   else /* this->class == token_sym */
@@ -229,7 +229,7 @@ symbol_translation (symbol_t *this)
 {
   /* Non-terminal? */
   if (this->class == token_sym
-      && this->user_token_number != SALIAS)
+      && this->user_token_number != USER_NUMBER_ALIAS)
     {
       /* A token which translation has already been set? */
       if (token_translations[this->user_token_number] != undeftoken->number)
@@ -998,10 +998,10 @@ parse_expect_decl (void)
 |                                                                    |
 | Two symbols are entered in the table, one for the token symbol and |
 | one for the literal.  Both are given the <type>, if any, from the  |
-| declaration.  The ->user_token_number of the first is SALIAS and   |
+| declaration.  The ->user_token_number of the first is              |
-| the ->user_token_number of the second is set to the number, if     |
+| USER_NUMBER_ALIAS and the ->user_token_number of the second is set |
-| any, from the declaration.  The two symbols are linked via         |
+| to the number, if any, from the declaration.  The two symbols are  |
-| pointers in their ->alias fields.                                  |
+| linked via pointers in their ->alias fields.                       |
 |                                                                    |
 | During OUTPUT_DEFINES_TABLE, the symbol is reported thereafter,    |
 | only the literal string is retained it is the literal string that  |
@@ -1014,7 +1014,7 @@ parse_thong_decl (void)
   token_t token;
   symbol_t *symbol;
   char *typename = 0;
-  int usrtoknum = SUNDEF;
+  int usrtoknum = USER_NUMBER_UNDEFINED;
 
   token = lex ();		/* fetch typename or first token */
   if (token == tok_typename)
@@ -1035,7 +1035,7 @@ parse_thong_decl (void)
     }
   symval->class = token_sym;
   symval->type_name = typename;
-  symval->user_token_number = SALIAS;
+  symval->user_token_number = USER_NUMBER_ALIAS;
   symbol = symval;
 
   token = lex ();		/* get number or literal string */
@@ -1666,7 +1666,7 @@ token_translations_init (void)
   for (i = 0; i < ntokens; ++i)
     {
       symbol_t *this = symbols[i];
-      if (this->user_token_number != SUNDEF)
+      if (this->user_token_number != USER_NUMBER_UNDEFINED)
 	{
 	  if (this->user_token_number > max_user_token_number)
 	    max_user_token_number = this->user_token_number;
@@ -1676,7 +1676,8 @@ token_translations_init (void)
     }
 
   /* If 256 is not used, assign it to error, to follow POSIX.  */
-  if (num_256_available_p && errtoken->user_token_number == SUNDEF)
+  if (num_256_available_p
+      && errtoken->user_token_number == USER_NUMBER_UNDEFINED)
     errtoken->user_token_number = 256;
 
   /* Set the missing user numbers. */
@@ -1686,7 +1687,7 @@ token_translations_init (void)
   for (i = 0; i < ntokens; ++i)
     {
       symbol_t *this = symbols[i];
-      if (this->user_token_number == SUNDEF)
+      if (this->user_token_number == USER_NUMBER_UNDEFINED)
 	this->user_token_number = ++max_user_token_number;
       if (this->user_token_number > max_user_token_number)
 	max_user_token_number = this->user_token_number;

src/symtab.c

@@ -38,7 +38,7 @@ symbol_new (const char *tag)
   res->number = NUMBER_UNDEFINED;
   res->prec = 0;
   res->assoc = right_assoc;
-  res->user_token_number = SUNDEF;
+  res->user_token_number = USER_NUMBER_UNDEFINED;
   res->alias = NULL;
   res->class = unknown_sym;
 

src/symtab.h

@@ -41,14 +41,12 @@ typedef enum
   nterm_sym		/* non-terminal */
 } symbol_class;
 
+
 /* Internal token numbers. */
 typedef short token_number_t;
 
-#define SUNDEF  -1              /* For undefined user number. */
-#define SALIAS	-9991		/* for symbol generated with an alias */
-
-#define NUMBER_UNDEFINED ((token_number_t) -1)
 
+typedef struct symbol_s symbol_t;
 struct symbol_s
 {
   /* The key, name of the symbol. */
@@ -61,14 +59,25 @@ struct symbol_s
   associativity assoc;
   int user_token_number;
 
-  /* Points to the other in the identifier-symbol pair for an
+  /* Points to the other in the identifier-symbol pair for an alias.
-     alias. Special value SALIAS in the identifier half of the
+     Special value USER_NUMBER_ALIAS in the identifier half of the
      identifier-symbol pair for an alias.  */
-  struct symbol_s *alias;
+  symbol_t *alias;
   symbol_class class;
 };
 
-typedef struct symbol_s symbol_t;
+/* Undefined user number.  */
+#define USER_NUMBER_UNDEFINED -1
+
+/* `symbol->user_token_number == USER_NUMBER_ALIAS' means this symbol
+   *has* (not is) a string literal alias.  For instance, `%token foo
+   "foo"' has `"foo"' numbered regularly, and `foo' numbered as
+   USER_NUMBER_ALIAS.  */
+#define USER_NUMBER_ALIAS -9991
+
+/* Undefined internal token number.  */
+#define NUMBER_UNDEFINED ((token_number_t) -1)
+
 
 /* A function to apply to each symbol. */
 typedef bool (*symbol_processor) PARAMS ((symbol_t *));

tests/regression.at

@@ -287,6 +287,32 @@ AT_CLEANUP
 
 
 
+## ------------------- ##
+## Token definitions.  ##
+## ------------------- ##
+
+
+AT_SETUP([Token definitions])
+
+# Bison managed, when fed with `%token 'f' "f"' to #define 'f'!
+AT_DATA([input.y],
+[[%token "end of file"
+%token 'a' "a"
+%token "b" 'b'
+%token "c" c
+%token d "d"
+%token e 'e'
+%token 'f' e
+%%
+exp: "a";
+]])
+
+AT_CHECK([bison input.y -o input.c])
+AT_CHECK([$CC $CFLAGS $CPPFLAGS input.c -c])
+AT_CLEANUP
+
+
+
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 ## Web2c Report.  ##
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