Require default %destructor/%printer to be declared using

[bison.git] / ChangeLog

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+2006-09-04  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+       Require default %destructor/%printer to be declared using
+       %symbol-default instead of an empty symbol list, and start working on
+       new per-type %destructor/%printer.  Discussed at
+       <http://lists.gnu.org/archive/html/bison-patches/2006-09/msg00007.html>.
+       * NEWS (2.3+): Add %symbol-default to example.
+       * bison.texinfo (Freeing Discarded Symbols): Likewise.
+       (Bison Symbols): Add entry for %symbol-default.
+       * src/parse-gram.y (PERCENT_SYMBOL_DEFAULT): New token.
+       (generic_symlist, generic_symlist_item): New nonterminals for creating
+       a list in which each item is a symbol, semantic type, or
+       %symbol-default.
+       (grammar_declaration): Use generic_symlist in %destructor and %printer
+       declarations instead of symbols.1 or an empty list.
+       (symbol_declaration, precedence_declaration, symbols.1): Update actions
+       for changes to symbol_list.
+       * src/reader.c: Update for changes to symbol_list.
+       * src/scan-code.l: Likewise.
+       * src/scan-gram.l: Scan new PERCENT_SYMBOL_DEFAULT token.
+       * src/symlist.c, src/symlist.h: Extend such that a list node may
+       represent a semantic type or a %symbol-default in addition to just an
+       ordinary symbol.  Add switched functions for setting %destructor's and
+       %printer's.
+       * tests/actions.at, tests/input.at: Add %symbol-default to all default
+       %destructor/%printer declarations.
+
+2006-08-23  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+       Whether the default %destructor/%printer applies to a particular symbol
+       isn't a question of whether the user *declares* that symbol (in %token,
+       for example).  It's a question of whether the user by any means
+       *defines* the symbol at all (by simply using a char token, for
+       example).  $end is defined by Bison whereas any other token with token
+       number 0 is defined by the user.  The error token is always defined by
+       Bison regardless of whether the user declares it with %token, but we
+       may one day let the user define error as a nonterminal instead.
+       * NEWS (2.3+): Say "user-defined" instead of "user-declared".
+       * doc/bison.texinfo (Freeing Discarded Symbols): Likewise, and document
+       the meaning of "user-defined".
+       * tests/actions.at (Default %printer and %destructor for user-declared
+       end token): Rename to...
+       (Default %printer and %destructor for user-defined end token): ...
+       this.
+
+       * src/symtab.c (symbol_destructor_get, symbol_printer_get): In the
+       computation of whether to apply the default, don't maintain a list of
+       every Bison-defined symbol.  Instead, just check for a first character
+       of '$', which a user symbol cannot have, and check for the error token.
+
+2006-08-21  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+       Don't apply the default %destructor or %printer to the error token,
+       $undefined, or $accept.  This change fits the general rule that the
+       default %destructor and %printer are only for user-declared symbols,
+       and it solves several difficulties that are described in the new test
+       cases listed below.
+       * src/symtab.c (symbol_destructor_get, symbol_printer_get): Implement.
+       * tests/actions.at (Default %printer and %destructor are not for error
+       or $undefined, Default %printer and %destructor are not for $accept):
+       New test cases.
+
 2006-08-19  Joel E. Denny  <jdenny@ces.clemson.edu>
 
        Allow %start after the first rule.