X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/4158e0a143725e7c9b6af17c653f49ade6e9a0cb..1e137b710b971175dbdce6defd61493801ca7e1b:/ChangeLog diff --git a/ChangeLog b/ChangeLog index f1cb7275..b7f45474 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,4 +1,558 @@ +2006-03-08 Joel E. Denny + + * doc/bison.texinfo (Introduction): Mention GLR and C++ as on the web + page. Say "you can use it" not "you may use it" as on the web page; + we're describing capabilities not granting permission. + +2006-03-06 Paul Eggert + + * data/glr.c (yyresolveLocations): Rename local variables to avoid + shadowing warnings. Use usual patter for iterating through RHS. + * tests/glr-regression.at + (Uninitialized location when reporting ambiguity): + Modify yylex so that it uses its argument, rather than trying + to rely on ARGSUSED (which doesn't work for gcc with warnings). + const char -> char const. + + * tests/Makefile.am ($(srcdir)/package.m4, maintainer-check-valgrind): + Don't use tabs inside commands; it messes up 'ps'. + Problem reported by twlevo. + +2006-03-06 Joel E. Denny + + * tests/glr-regression.at (Uninitialized location when reporting + ambiguity): New test case. + * data/glr.c (yyresolveLocations): New function, which uses + YYLLOC_DEFAULT. + (yyresolveValue): Invoke yyresolveLocations before reporting an + ambiguity. + * doc/bison.texinfo (Default Action for Locations): Note + YYLLOC_DEFAULT's usage for ambiguity locations. + (GLR Semantic Actions): Cross-reference those notes. + +2006-03-04 Joel E. Denny + + * tests/glr-regression.at (Leaked semantic values when reporting + ambiguity): Remove unnecessary union and type declarations. + (Leaked lookahead after nondeterministic parse syntax error): New test + case. + * data/glr.c (yyparse): Check for zero stacks remaining before + attempting to shift the lookahead so that you don't lose it. + +2006-03-02 Joel E. Denny + + Avoid memory leaks by not invoking longjmp in yyreportAmbiguity. + * tests/glr-regression.at (Leaked semantic values when reporting + ambiguity): New test case. + * data/glr.c (yyreportAmbiguity): Invoke yyyerror directly and return + yyabort rather than invoking yyFail, which invokes longjmp. Remove the + now unnecessary yystackp parameter. + (yyresolveValue): Return yyreportAmbiguity's result. Now the necessary + destructors can be called. + + * tests/glr-regression.at: Don't invoke bison with `-t' unnecessarily + in existing testcases. + +2006-03-02 Joel E. Denny + + Don't leak semantic values for parent RHS when a user action cuts the + parser, and clean up related code a bit. + * tests/glr-regression.at (Leaked merged semantic value if user action + cuts parse): Rename to... + (Leaked semantic values if user action cuts parse): ... this. Add check + for leaked parent RHS values. + * data/glr.c (yydestroyGLRState): In debugging output, distinguish + between an unresolved state (non-empty chain of semantic options) and + an incomplete one (signaled by an empty chain). + (yyresolveStates): Document the interface. Move all manipulation of a + successfully or unsuccessfully resolved yyGLRState to... + (yyresolveValue): ... here so that yyresolveValue always leaves a + yyGLRState with consistent data and thus is easier to understand. + Remove the yyvalp and yylocp parameters since they are always just + taken from the yys parameter. When reporting a discarded merged value + in debugging output, note that it is incompletely merged. Document the + interface. + (yyresolveAction): If resolving any of the RHS states fails, destroy + them all rather than leaking them. Thus, as long as user actions are + written to clean up the RHS correctly, yyresolveAction always cleans up + the RHS of a semantic option. Document the interface. + +2006-02-27 Paul Eggert + + * data/glr.c (yyexpandGLRStack): Catch an off-by-one error that + led to a segmentation fault in GNU Pascal. Problem reported + by Waldek Hebisch. + +2006-02-21 Joel E. Denny + + * doc/bison.texinfo (Mid-Rule Actions): Explain how to bury a + mid-rule action inside a nonterminal symbol in order to declare a + destructor for its semantic value. + +2006-02-16 Paul Eggert + + * data/yacc.c [(! defined yyoverflow || YYERROR_VERBOSE) && ! + YYSTACK_USE_ALLOCA && ! defined YYSTACK_ALLOC && defined + __cplusplus && ! defined _STDLIB_H && ! + ((defined YYMALLOC || defined malloc) && (defined YYFREE || + defined free))]: Include rather than rolling our own + declarations of malloc and free, to avoid problems with + incompatible declarations (using 'throw') C++'s stdlib.h. This + should fix Debian bug 340012 + , + reported by Guillaume Melquiond. + +2006-02-13 Paul Eggert + + * NEWS: Clarify symbols versus types in unused-value warnings. + + * configure.ac (AC_INIT): Bump version number. + +2006-02-13 Paul Eggert + + * NEWS: Version 2.1a. + * tests/headers.at (AT_TEST_CPP_GUARD_H): Declare yyerror and yylex, + since C99 requires this. + +2006-02-11 Paul Eggert + + * m4/c-working.m4: New file. + * configure.ac (BISON_TEST_FOR_WORKING_C_COMPILER): Use it. + +2006-02-10 Paul Eggert + + * Makefile.maint: Merge from coreutils. + +2006-02-09 Paul Eggert + + More portability fixes for problems summarized by Nelson H. F. Beebe. + + * m4/cxx.m4 (BISON_TEST_FOR_WORKING_CXX_COMPILER): Catch a + configuration screwup "./configure CC=/opt/SUNWspro/bin/c89 + CFLAGS="-xarch=generic64" CXX=/opt/SUNWspro/bin/CC + LDFLAGS="-xarch=generic64" with Sun C 5.7 on Solaris 10; this + messes up because C++ code is compiled in 32-bit mode but linked + in 64-bit mode. + +2006-02-08 Paul Eggert + + More portability fixes for problems summarized by Nelson H. F. Beebe. + + * doc/bison.texinfo (Calc++ Scanner): Work around a bug in flex + 2.5.31. This resembles the 2005-10-10 patch to src/scan-skel.l. + + * examples/calc++/Makefile.am (check_PROGRAMS): Renamed from + nodist_PROGRAMS, since we don't need to actually compile the + example if we're just doing a plain 'make'. This avoids bothering + the installer unnecessarily about problems due to weird C++ + compilers. + +2006-02-06 Paul Eggert + + More portability fixes for problems summarized by Nelson H. F. Beebe. + + * tests/headers.at (AT_TEST_CPP_GUARD_H): Use #include <...> rather + than #include "...", and compile with -I'.'. The old method was + not portable, according to Posix and the C standard, and it does + not work with Sun C 5.7, where previous #line directives affect + the working directory used in later #include "..." directives. + +2006-02-06 Juan Manuel Guerrero + + Various DJGGP specific issues in /djgpp + +2006-02-02 Paul Eggert + + More portability fixes for problems summarized by Nelson H. F. Beebe. + + * m4/cxx.m4 (BISON_TEST_FOR_WORKING_CXX_COMPILER): Check that + '#include ' works and that you can apply ++ to iterators. + +2006-02-01 Paul Eggert + + Work around portability problems summarized by Nelson H. F. Beebe in + . + + * m4/cxx.m4 (BISON_TEST_FOR_WORKING_CXX_COMPILER): Check + that '#include ' works. + + * data/lalr1.cc (yytranslate_): No longer inline, to work around a + porting problem to g++ 3.4.3 on Darwin 7.9.0, where g++ complained + "warning: sorry: semantics of inline function static data `const + unsigned char translate_table[262]' are wrong (you'll wind up with + multiple copies)". + + * lib/bbitset.h (struct bitset_vtable): Rename members not, and, + or, xor to not_, and_, or_, and xor_, respectively. This works + around a bug in GCC 3.4.3 on Irix 6.5, which apparently has a + random system header somewhere that includes the equivalent of + . + + * tests/headers.at (AT_TEST_CPP_GUARD_H): Don't assume that "$CC + -E" works; it apparently doesn't work with PathScale EKO Compiler + Suite Version 2.0. + +2006-01-30 Joel E. Denny + + During deterministic GLR operation, user actions should be able to + influence the parse by changing yychar. To make this easier to fix and + to make glr.c easier to evolve in general, don't maintain yytoken in + parallel with yychar; just compute yytoken when needed. + * tests/glr-regression.at (Incorrect lookahead during deterministic + GLR): Check that setting yychar in a user action has the intended + effect. + * data/glr.c (yyGLRStack): Remove yytokenp member. + (yyclearin): Don't set *yytokenp. + (yyprocessOneStack, yyreportSyntaxError, yyrecoverSyntaxError): Examine + yychar rather than *yytokenp to determine the current lookahead. + Compute yytoken locally when needed. + (yyparse): Likewise. Remove the local yytoken that yytokenp used to + point to. + + * doc/bison.texinfo (Bison Options): Remove stray sentence fragment + after `--report' documentation. + +2006-01-30 Paul Eggert + + * src/parse-gram.y (grammar_declaration): Location of printer + symbol is @1, not list->location. Bug reported by twlevo. + * tests/input.at (Incompatible Aliases): Adjust to above change. + +2006-01-29 Paul Eggert + + * tests/input.at (AT_CHECK_UNUSED_VALUES): Remove. Instead, do + all the test at once. This makes the output easier to read in the + normal case. + + Fix a longstanding bug uncovered by bro-0.9a9/src/parse.y, which I + got from . The bug is that + when two actions appeared in succession, the second one was + scanned before the first one was added to the grammar rule + as a midrule action. Bison then output the incorrect warning + "parse.y:905.17-906.36: warning: unused value: $3". + * src/parse-gram.y (BRACED_CODE, action): These are no longer + associated with a value. + (rhs): Don't invoke grammar_current_rule_action_append. + (action): Invoke it here instead. + * src/reader.c (grammar_midrule_action): Now extern. + (grammar_current_rule_action_append): Don't invoke + grammar_midrule_action; that is now the scanner's job. + * src/reader.h (last_string, last_braced_code_loc): + (grammar_midrule_action): New decls. + * src/scan-gram.l (last_string): Now extern, sigh. + (last_braced_code_loc): New extern variable. + ("{"): Invoke grammar_midrule_action if the current + rule already has an action. + ("}"): Set last_braced_code_loc before returning. + * tests/input.at (AT_CHECK_UNUSED_VALUES): + Add some tests to check that the above changes fixed the bug. + +2006-01-27 Paul Eggert + + * src/reader.c (symbol_should_be_used): Renamed from symbol_typed_p. + All used changed. Check whether the symbol has a destructor, + not whether it is typed. + * tests/input.at (AT_CHECK_UNUSED_VALUES): Add a destructor, so + that the values are still reported as unused. All line numbers + adjusted. + +2006-01-23 Paul Eggert + + Work around a bug in bro 0.8, which underparenthesizes its + definition of YYLLOC_DEFAULT. + * data/glr.c: Change all uses of YYLLOC_DEFAULT to parenthesize + their arguments. + * data/lalr1.cc: Likewise. + * data/yacc.cc: Likewise. + +2006-01-22 Paul Eggert + + Work around a bug in Pike 7.0, and give the Pike folks a + better way to override the usual int widths. + * data/yacc.c (b4_int_type): Use yytype_uint8, etc., so that the + user can override the types. + (short): #undef, to work around a bug in Pike 7.0. + (yytype_uint8, yytype_int8, yytype_uint16, yytype_int16): New types. + (union yyalloc.yyss): Use yytype_int16 rather than short. + All uses changed. + (yysigned_char): Remove. + * src/parse-gram.y (YYTYPE_UINT8, YYTYPE_INT8, YYTYPE_UINT16): + (YYTYPE_INT16): New macros, to test the new facility in yacc.c. + * tests/regression.at (Web2c Actions): Adjust to above changes. + + * src/reader.c (check_and_convert_grammar): New function. + (reader): Close the input file even if something went wrong during + parsing. Minor file descriptor leak reported by twlevo. + + * src/assoc.c (assoc_to_string): Use a default: abort (); case + to pacify gcc -Wswitch-default. + * src/scan-gram.l (adjust_location): Use a default: break; case + to pacify gcc -Wswitch-default. + * src/scan-skel.h (skel_get_lineno, skel_get_in, skel_get_out): + (skel_get_leng, skel_get_text, skel_set_lineno, skel_set_in): + (skel_set_out, skel_get_debug, skel_set_debug, skel_lex_destroy): + Move these decls to scan-skel.l, since they don't need to be + visible elsewhere. + * src/scan-skel.l: Accept the above decls. + (skel_lex): New decl, to pacify GCC when unpatched flex 2.5.31 + is used. + +2006-01-21 Paul Eggert + + * Makefile.cfg (local-checks-to-skip): Add changelog-check, + since we don't want to insist on a version number at the start + of the changelog every time. + * Makefile.maint: Sync from coreutils a bit better. + (sc_trailing_blank): Renamed from sc_trailing_space. + All uses changed. + (sc_no_if_have_config_h, sc_require_config_h): + (sc_prohibit_assert_without_use): New rules. + (sc_obsolete_symbols): Don't catch Makefile.maint itself. + (sc_dd_max_sym_length): Fix leading spaces in rule. + (sc_system_h_headers): Prefix with @. + (sc_useless_cpp_parens, m4-check): Output line numbers. + (changelog-check): Allow version only in head. + * data/c.m4: Use "defined FOO" instead of "defined (FOO)", to + satisfy new Makefile.maint rule. + * data/glr.c: Likewise. + * data/glr.cc: Likewise. + * data/lalr1.cc: Likewise. + * data/yacc.c: Likewise. + * lib/ebitsetv.c: Likewise. + * lib/lbitset.c: Likewise. + * lib/subpipe.c: Likewise. + * lib/timevar.c: Likewise. + * src/system.h: Likewise. + * data/yacc.c (YYSTYPE): Don't generate trailing spaces in output. + * djgpp/Makefile.maint: Add copyright notice. + * djgpp/README.in: Likewise. + * djgpp/config.bat: Likewise. + * djgpp/config.site: Likewise. + * djgpp/config_h.sed: Likewise. + * djgpp/djunpack.bat: Likewise. + * djgpp/config.sed: Fix copyright notice to match standard format. + * djgpp/subpipe.h: Likewise. + * lib/bitsetv-print.c: Likewise. + * lib/bitsetv.c: Likewise. + * lib/subpipe.h: Likewise. + * lib/timevar.c: Likewise. + * lib/timevar.h: Likewise. + * djgpp/subpipe.c: Use standard recipe for config.h. + * lib/abitset.c: Likewise. + * lib/bitset.c: Likewise. + * lib/bitset_stats.c: Likewise. + * lib/bitsetv-print.c: Likewise. + * lib/bitsetv.c: Likewise. + * lib/ebitsetv.c: Likewise. + * lib/get-errno.c: Likewise. + * lib/lbitset.c: Likewise. + * lib/subpipe.c: Likewise. + * lib/timevar.c: Likewise. + * lib/vbitset.c: Likewise. + * tests/local.at: Likewise. + * src/scan-gram.l: Don't include verify.h, since system.h does + that for us. + * .x-sc_require_config_h: New file. + * .x-sc_unmarked_diagnostics: New file. + +2006-01-20 Paul Eggert + + Be a bit more systematic about using 'abort'. + * lib/abitset.c (abitset_test): Remove ATTRIBUTE_UNUSED; not needed. + * lib/bitset.c (bitset_bytes, bitset_init, bitset_op4_cmp): + Put 'default: abort ();' before some other case, to satisfy older + pedantic compilers. + * lib/bitset_stats.c (bitset_stats_init): Likewise. + * lib/ebitset.c (ebitset_elt_find, ebitset_op3_cmp): Likewise. + * lib/lbitset.c (lbitset_elt_find, lbitset_op3_cmp): Likewise. + * src/conflicts.c (resolve_sr_conflict): Likewise. + * src/vcg.c (get_color_str, get_textmode_str, get_shape_str): + (get_decision_str, get_orientation_str, get_node_alignment_str): + (get_arrow_mode_str, get_crossing_type_str, get_view_str): + (get_linestyle_str, get_arrowstyle_str): Likewise. + * src/conflicts.c (resolve_sr_conflict): + Use a default case rather than one for the one remaining enum + value, to catch invalid enum values as well. + * src/lalr.c (set_goto_map, map_goto): + Prefer "assert (FOO);" to "if (!FOO) abort ();". + * src/nullable.c (nullable_compute, token_definitions_output): + Likewise. + * src/reader.c (packgram, reader): Likewise. + * src/state.c (transitions_to, state_new, state_reduction_find): + Likewise. + * src/symtab.c (symbol_user_token_number_set, symbol_make_alias): + (symbol_pack): Likewise. + * src/tables.c (conflict_row, pack_vector): Likewise. + * src/scan-skel.l (QPUTS): Remove unnecessary parens. + (BASE_QPUTS, "@output ".*\n): Remove unnecessary asserts. + * src/system.h: Don't include . + (assert): New macro. + + * doc/bison.texinfo (Prologue, Rules, Actions, Union Decl, Action Decl): + (Destructor Decl, Parser Function, Pure Calling): + Describe rules for braces inside C code more carefully. + +2006-01-19 Paul Eggert + + Fix some porting glitches found by Nelson H. F. Beebe. + * lib/abitset.c (abitset_resize): Rewrite to avoid warnings from + compilers that don't understand that abort () does not return. + * src/state.c (transitions_to): Likewise. + * m4/cxx.m4 (BISON_TEST_FOR_WORKING_CXX_COMPILER): Check + that '#include ' works. + * src/system.h (INT8_MIN, INT16_MIN, INT32_MIN, INT8_MAX): + (INT16_MAX, UINT8_MAX, INT32_MAX, UINT16_MAX, UINT32_MAX): + #undef if ! defined __STDC_VERSION__ || __STDC_VERSION__ < 199901, + for the benefit of some pre-C99 compilers. + + * bootstrap: Undo changes to gnulib files that autoreconf made. + + Minor fixups to get 'make maintainer-check' to work. + * configure.ac: Don't use -Wnested-externs, as it's incompatible + with the new verify.h implementation. + * data/c.m4 (b4_yy_symbol_print_generate): YYUSE (yyoutput). + * data/glr.c (YYUSE): Depend on __GNUC__ as well. + * data/yacc.c (YYUSE): Likewise. + * data/lalr1.cc (yysyntax_error_): YYUSE (yystate). + * lib/subpipe.c (end_of_output_subpipe): The args are unused. + * src/parse-gram.y (declaration): Don't pass a string constant + to a function that expects char *, since GCC might complain + about the constant value. + * src/reader.c (symbol_typed_p): Add parens to pacify GCC. + * tests/cxx-type.at (_AT_TEST_GLR_CXXTYPES): #undef yylloc and yylval + before #defining them. + * tests/glr-regression.at + (Incorrectly initialized location for empty right-hand side in GLR): + In yyerror, use the msg arg. + (Corrupted semantic options if user action cuts parse): + (Incorrect lookahead during deterministic GLR): + (Incorrect lookahead during nondeterministic GLR): + Don't name a local var 'index'; it shadows string.h's 'index'. + +2006-01-19 Akim Demaille + + * tests/calc.at (_AT_DATA_CALC_Y): Initialize the whole initial + location, not just parts of it. + +2006-01-18 Paul Eggert + + * NEWS: Document the fact that multiple %unions are now allowed. + * doc/bison.texinfo (Union Decl): Likewise. + * TODO: This feature is now implemented, so remove it from + the wishlist. + + * Makefile.maint: Merge with coreutils Makefile.maint. + (CVS_LIST): Use build-aux version if available. + (VERSION_REGEXP): New macro. + (syntax-check-rules): Add sc_no_if_have_config_h, + sc_prohibit_assert_without_use, sc_require_config_h, + sc_useless_cpp_parens. + (sc_obsolete_symbols): Check for O_NDELAY. + (sc_dd_max_sym_length): Track coreutils. + (sc_unmarked_diagnostics): Look in all files, not just *.c. + (sc_useless_cpp_parens): New rule. + (news-date-check): Look for version or today's date. + (changelog-check): Don't require version number near head. + (copyright-check): Use current year instead of hardwiring 2005. + (my-distcheck): Depend on $(release_archive_dir)/$(prev-tgz). + (announcement): Add --gpg-key-ID. + + * djgpp/config.sed: Add copyright notice, and replace "filesystem" + with "file system". + + Avoid undefined behavior that addressed just before the start of an + array. Problem reported by twlevo. + * src/reader.c (packgram): Prepend a new sentinel before ritem. + * src/lalr.c (build_relations): Rely on new sentinel. + * src/gram.c (gram_free): Adjust to new sentinel. + +2006-01-12 Joel E. Denny + + * data/glr.c (yyGLRStateSet): Rename yylookaheadStatuses to + yylookaheadNeeds. All uses updated. + (yysplitStack): Rename local yynewLookaheadStatuses to + yynewLookaheadNeeds. + * data/glr-regression.at (Incorrect lookahead during nondeterministic + GLR): In comments, change `lookahead status' to `lookahead need'. + +2006-01-11 Paul Hilfinger + + * data/glr.c (yysplitStack): A little stylistic rewrite. + +2006-01-11 Paul Hilfinger + + * data/glr.c (yyaddDeferredAction): Flesh out the comment. + +2006-01-11 Joel E. Denny + + * doc/bison.texinfo: Fix some typos. + (GLR Semantic Actions): New subsection discussing special + considerations because GLR semantic actions might be deferred. + (Actions): Mention look-ahead usage of yylval. + (Actions and Locations): Mention look-ahead usage of yylloc. + (Special Features for Use in Actions): Add YYEOF entry and mention it + in the yychar entry. + In the yychar entry, remove mention of the local yychar case (pure + parser) since this is irrelevant information when writing semantic + actions and since it's already discussed in `Bison Symbols' where + yychar is otherwise described as an external variable. + In the yychar entry, don't call it the `current' look-ahead since it + isn't when semantic actions are deferred. + In the yychar and yyclearin entries, add note about deferred semantic + actions. + Add yylloc and yylval entries discussing look-ahead usage. + (Look-Ahead Tokens): When discussing yychar, don't call it the + `current' look-ahead, and do mention yylval and yylloc. + (Error Recovery): Cross-reference `Action Features' when mentioning + yyclearin. + (Bison Symbols): In the yychar entry, don't call it the `current' + look-ahead. + In the yylloc and yylval entries, mention look-ahead usage. + +2006-01-08 Joel E. Denny + + * tests/glr-regression.at: Update copyright year to 2006. + +2006-01-06 Joel E. Denny + + * data/glr.c (yyGLRStateSet): Add yybool* yylookaheadStatuses member to + use during nondeterministic operation to track which stacks have + actually needed the current lookahead. + (yyinitStateSet, yyfreeStateSet, yyremoveDeletes, yysplitStack): + Allocate, deallocate, resize, and otherwise shuffle space for + yylookaheadStatuses in parallel with yystates member of yyGLRStateSet. + (yysplitStack, yyprocessOneStack, yyparse): Set lookahead status + appropriately during nondeterministic operation. + (yySemanticOption): Add int yyrawchar, YYSTYPE yyval, and YYLTYPE yyloc + members to store the current lookahead to be used by the deferred + user action. + (yyaddDeferredAction): Add size_t yyk parameter specifying the stack + from which the RHS is taken. Set the lookahead members of the new + yySemanticOption according to the lookahead status for stack yyk. + (yyglrShiftDefer, yyglrReduce): Pass yyk parameter on to + yyaddDeferredAction. + (yyresolveAction): Set yychar, yylval, and yylloc to the lookahead + members of yySemanticOption before invoking yyuserAction, and then set + them back to their current values afterward. + (yyparse): Set yychar = YYEMPTY where yytoken = YYEMPTY. + (yyreportAmbiguity): Add /*ARGSUSED*/ to pacify lint. + * tests/glr-regression.at: Remove `.' from the ends of recent test case + titles for consistency. + (Leaked merged semantic value if user action cuts parse): In order to + suppress lint warnings, use arguments in merge function, and assign + char value < 128 in main. + (Incorrect lookahead during deterministic GLR): New test case. + (Incorrect lookahead during nondeterministic GLR): New test case. + 2006-01-06 Joel E. Denny + + * data/c.m4 (b4_yy_symbol_print_generate): In yy_symbol_print, accept + !yyvaluep as signal that no semantic value is available to print. + * data/glr.c (yydestroyGLRState): If state is not resolved, don't try + to print a semantic value. + +2006-01-06 Joel E. Denny + * tests/glr-regression.at: For consistency with my newer test cases, don't thank myself. @@ -938,7 +1492,7 @@ 2005-09-19 Akim Demaille - * NEWS, configure.ac: Bump to 2.1a. + * NEWS, configure.ac: update version number to 2.1a. 2005-09-16 Paul Eggert