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GLR parsers sometimes raise parse errors instead of performing the

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default reduction.
Reported by Charles-Henry de Boysson.
* tests/calc.at (_AT_CHECK_CALC, _AT_CHECK_CALC_ERROR): Don't
check the length of the	traces when %glr.
(_AT_CHECK_CALC_ERROR): Also skip `^Stack' lines, coming from
GLR's traces.
(AT_CHECK_CALC_LALR, AT_CHECK_CALC_GLR): New.
Test GLR parsers.
* data/glr.c (YYLEFTMOST_STATE): Fix its value.
(yyltype): Remove the yy prefix from the member names.
(yytable): Complete its comment.
(yygetLRActions): Map error action number from YYTABLE from
YYTABLE_NINF to 0.
(yyisErrorAction): No longer compare YYACTION to YYPACT_NINF
(which was a bug: it should have been YYTABEL_NINF, and yet it was
not satisfying as we could compare an YYACTION computed from
YYDEFACT to YYTABLE_NINF although they are unrelated): 0 is the
only value for error actions.
(yyreportParseError): In verbose parse error messages, don't issue
`error' in the list of expected tokens.
* data/yacc.c (yyparse) <yybackup>: Rewrite the decoding of the
next action to perform to match glr.c's decoding.
(yytable): Complete its comment.
This commit is contained in:
Akim Demaille
2002-10-13 14:25:14 +00:00
parent 3b7d4eb2cd
commit f50adbbdb0
6 changed files with 213 additions and 129 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
ChangeLog
View File

@@ -1,3 +1,31 @@
2002-10-13 Akim Demaille <akim@epita.fr>
GLR parsers sometimes raise parse errors instead of performing the
default reduction.
Reported by Charles-Henry de Boysson.
* tests/calc.at (_AT_CHECK_CALC, _AT_CHECK_CALC_ERROR): Don't
check the length of the traces when %glr.
(_AT_CHECK_CALC_ERROR): Also skip `^Stack' lines, coming from
GLR's traces.
(AT_CHECK_CALC_LALR, AT_CHECK_CALC_GLR): New.
Test GLR parsers.
* data/glr.c (YYLEFTMOST_STATE): Fix its value.
(yyltype): Remove the yy prefix from the member names.
(yytable): Complete its comment.
(yygetLRActions): Map error action number from YYTABLE from
YYTABLE_NINF to 0.
(yyisErrorAction): No longer compare YYACTION to YYPACT_NINF
(which was a bug: it should have been YYTABEL_NINF, and yet it was
not satisfying as we could compare an YYACTION computed from
YYDEFACT to YYTABLE_NINF although they are unrelated): 0 is the
only value for error actions.
(yyreportParseError): In verbose parse error messages, don't issue
`error' in the list of expected tokens.
* data/yacc.c (yyparse) <yybackup>: Rewrite the decoding of the
next action to perform to match glr.c's decoding.
(yytable): Complete its comment.
2002-10-13 Paul Eggert <eggert@twinsun.com>
Fix problem reported by Henrik Grubbstroem in

7
NEWS
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@@ -7,6 +7,13 @@ Changes in version 1.50a:
* Indonesian translation thanks to Tedi Heriyanto.
* GLR parsers
Fix spurious parse errors.
* Pure parsers
Some people redefine yyerror to steal yyparse' private variables.
Reenable this trick until an official feature replaces it.
Changes in version 1.50, 2002-10-04:
* GLR parsing

1
THANKS
View File

@@ -10,6 +10,7 @@ Arnold Robbins arnold@skeeve.com
Art Haas ahaas@neosoft.com
Benoit Perrot benoit.perrot@epita.fr
Bruce Lilly blilly@erols.com
Charles-Henri de Boysson deboys_c@epita.fr
Cris Bailiff c.bailiff+bison@awayweb.com
Cris van Pelt cris@amf03054.office.wxs.nl
Daniel Hagerty hag@gnu.org

52
data/glr.c
View File

@@ -169,10 +169,10 @@ typedef union b4_stype yystype;
typedef struct yyltype
{
]b4_location_if([
int yyfirst_line;
int yyfirst_column;
int yylast_line;
int yylast_column;])[
int first_line;
int first_column;
int last_line;
int last_column;])[
} yyltype;
# define YYLTYPE ]b4_ltype[
# define YYLTYPE_IS_TRIVIAL 1
@@ -333,7 +333,8 @@ static const ]b4_int_type_for([b4_pgoto])[ yypgoto[] =
/* YYTABLE[YYPACT[STATE-NUM]]. What to do in state STATE-NUM. If
positive, shift that token. If negative, reduce the rule which
number is the opposite. If zero, do what YYDEFACT says. */
number is the opposite. If zero, do what YYDEFACT says.
If YYTABLE_NINF, parse error. */
#define YYTABLE_NINF ]b4_table_ninf[
static const ]b4_int_type_for([b4_table])[ yytable[] =
{
@@ -396,10 +397,10 @@ int yyparse (void);
#ifndef YYLLOC_DEFAULT
# define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN) \
yyCurrent.yyfirst_line = YYRHSLOC(yyRhs,1).yyfirst_line; \
yyCurrent.yyfirst_column = YYRHSLOC(yyRhs,1).yyfirst_column; \
yyCurrent.yylast_line = YYRHSLOC(yyRhs,YYN).yylast_line; \
yyCurrent.yylast_column = YYRHSLOC(yyRhs,YYN).yylast_column;
yyCurrent.first_line = YYRHSLOC(yyRhs,1).first_line; \
yyCurrent.first_column = YYRHSLOC(yyRhs,1).first_column; \
yyCurrent.last_line = YYRHSLOC(yyRhs,YYN).last_line; \
yyCurrent.last_column = YYRHSLOC(yyRhs,YYN).last_column;
#endif
/* YYLEX -- calling `yylex' with the right arguments. */
@@ -705,16 +706,21 @@ yygetLRActions (yyStateNum yystate, int yytoken,
int* yyaction, const short** yyconflicts)
{
int yyindex = yypact[yystate] + yytoken;
if (yyindex < 0 || yyindex > YYLAST || yycheck[yyindex] != yytoken)
if (yyindex < 0 || YYLAST < yyindex || yycheck[yyindex] != yytoken)
{
*yyaction = -yydefact[yystate];
*yyconflicts = yyconfl;
}
else
else if (yytable[yyindex] != YYTABLE_NINF)
{
*yyaction = yytable[yyindex];
*yyconflicts = yyconfl + yyconflp[yyindex];
}
else
{
*yyaction = 0;
*yyconflicts = yyconfl + yyconflp[yyindex];
}
}
static inline yyStateNum
@@ -722,7 +728,7 @@ yyLRgotoState (yyStateNum yystate, yySymbol yylhs)
{
int yyr;
yyr = yypgoto[yylhs - YYNTOKENS] + yystate;
if (yyr >= 0 && yyr <= YYLAST && yycheck[yyr] == yystate)
if (0 <= yyr && yyr <= YYLAST && yycheck[yyr] == yystate)
return yytable[yyr];
else
return yydefgoto[yylhs - YYNTOKENS];
@@ -737,7 +743,7 @@ yyisShiftAction (int yyaction)
static inline bool
yyisErrorAction (int yyaction)
{
return yyaction == 0 || yyaction == YYPACT_NINF;
return yyaction == 0;
}
/* GLRStates */
@@ -1256,7 +1262,7 @@ yyresolveAction (yySemanticOption* yyopt, yyGLRStack* yystack,
}
#if YYDEBUG
static yyGLRState YYLEFTMOST_STATE = { 0, NULL, -1, 0, { NULL } };
static yyGLRState YYLEFTMOST_STATE = { 0, 0, -1, NULL, 0, { NULL } };
static void yyreportTree (yySemanticOption* yyx, int yyindent)
{
@@ -1524,7 +1530,7 @@ yyreportParseError (yyGLRStack* yystack, YYSTYPE* yylvalp, YYLTYPE* yyllocp)
{
yyprefix = ", expecting ";
for (yyx = yyn < 0 ? -yyn : 0; yyx < yytname_size; yyx += 1)
if (yycheck[yyx + yyn] == yyx)
if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR)
{
yyp += sprintf (yyp, "%s%s", yyprefix, yytokenName (yyx));
yyprefix = " or ";
@@ -1540,13 +1546,9 @@ yyreportParseError (yyGLRStack* yystack, YYSTYPE* yylvalp, YYLTYPE* yyllocp)
}
}
/* Recover from a syntax error on STACK, assuming that TOKENP,
/* Recover from a syntax error on YYSTACK, assuming that YYTOKENP,
YYLVALP, and YYLLOCP point to the syntactic category, semantic
value, and location of the lookahead.
NOTE: This uses the panic-mode recovery algorithm described in the
Bison documentation, which differs from what is in bison.simple.
Specifically, this routine performs no reductions before shifting
the error token. */
value, and location of the lookahead. */
static void
yyrecoverParseError (yyGLRStack* yystack, YYSTYPE* yylvalp, YYLTYPE* yyllocp)
{
@@ -1855,10 +1857,10 @@ b4_location_if(
[#ifndef YYLTYPE
typedef struct yyltype
{
int yyfirst_line;
int yyfirst_column;
int yylast_line;
int yylast_column;
int first_line;
int first_column;
int last_line;
int last_column;
} yyltype;
# define YYLTYPE yyltype
#endif

24
data/yacc.c
View File

@@ -414,7 +414,8 @@ static const b4_int_type_for([b4_pgoto]) yypgoto[[]] =
/* YYTABLE[[YYPACT[STATE-NUM]]]. What to do in state STATE-NUM. If
positive, shift that token. If negative, reduce the rule which
number is the opposite. If zero, do what YYDEFACT says. */
number is the opposite. If zero, do what YYDEFACT says.
If YYTABLE_NINF, parse error. */
#define YYTABLE_NINF b4_table_ninf
static const b4_int_type_for([b4_table]) yytable[[]] =
{
@@ -917,23 +918,22 @@ yybackup:
YYDPRINTF ((stderr, "\n"));
}
/* Set YYN to the action to take in STATE on seeing token YYCHAR1.
Result YYN means
- YYN < 0: Reduce on rule -YYN.
- YYN = 0: Error.
- YYN > 0: Shift to state YYN. */
yyn += yychar1;
if (yyn < 0 || YYLAST < yyn || yycheck[yyn] != yychar1)
goto yydefault;
/* Defaulted action (reduction). */
yyn = -yydefact[yystate];
else if (yytable[yyn] != YYTABLE_NINF)
yyn = yytable[yyn];
/* yyn is what to do for this token type in this state.
Negative => reduce, -yyn is rule number.
Positive => shift, yyn is new state.
New state is final state => don't bother to shift,
just return success.
0, or most negative number => error. */
else
yyn = 0;
if (yyn < 0)
{
if (yyn == YYTABLE_NINF)
goto yyerrlab;
yyn = -yyn;
goto yyreduce;
}

116
tests/calc.at
View File

@@ -16,8 +16,6 @@
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
AT_BANNER([[Simple Calculator.]])
## ---------------------------------------------------- ##
## Compile the grammar described in the documentation. ##
## ---------------------------------------------------- ##
@@ -275,8 +273,8 @@ main (int argc, const char **argv)
# Produce `calc.y'.
m4_define([AT_DATA_CALC_Y],
[_AT_DATA_CALC_Y($[1], $[2], $[3],
[m4_bmatch([$1], [--yyerror-verbose],
[[%error-verbose]])])])
[m4_bpatsubst([$1], [--[^ ]*])])
])
@@ -284,17 +282,22 @@ m4_define([AT_DATA_CALC_Y],
# ------------------------------------------------------------
# Run `calc' on INPUT and expect no STDOUT nor STDERR.
#
# If BISON-OPTIONS contains `--debug', then NUM-STDERR-LINES is the number
# of expected lines on stderr.
# If BISON-OPTIONS contains `%debug' but not `%glr-parser', then
# NUM-STDERR-LINES is the number of expected lines on stderr.
#
# We don't count GLR's traces yet, since its traces are somewhat
# different from LALR's.
m4_define([_AT_CHECK_CALC],
[AT_DATA([[input]],
[[$2
]])
AT_PARSER_CHECK([./calc input], 0, [], [stderr])dnl
AT_CHECK([wc -l <stderr | sed 's/[[^0-9]]//g'], 0,
[m4_bmatch([$1], [--debug],
[$3], [0])
])
AT_PARSER_CHECK([./calc input], 0, [], [stderr])
m4_bmatch([$1],
[%debug.*%glr\|%glr.*%debug],
[],
[%debug],
[AT_CHECK([wc -l <stderr | sed 's/[[^0-9]]//g'], 0, [$3
])])
])
@@ -309,12 +312,12 @@ AT_CHECK([wc -l <stderr | sed 's/[[^0-9]]//g'], 0,
# If BISON-OPTIONS contains `--location', then make sure the ERROR-LOCATION
# is correctly output on stderr.
#
# If BISON-OPTIONS contains `--yyerror-verbose', then make sure the
# If BISON-OPTIONS contains `%error-verbose', then make sure the
# IF-YYERROR-VERBOSE message is properly output after `parse error, '
# on STDERR.
#
# If BISON-OPTIONS contains `--debug', then NUM-STDERR-LINES is the number
# of expected lines on stderr.
# If BISON-OPTIONS contains `%debug' but not `%glr', then NUM-STDERR-LINES
# is the number of expected lines on stderr.
m4_define([_AT_CHECK_CALC_ERROR],
[m4_bmatch([$2], [^/],
[AT_PARSER_CHECK([./calc $2], 0, [], [stderr])],
@@ -322,9 +325,11 @@ m4_define([_AT_CHECK_CALC_ERROR],
[[$2
]])
AT_PARSER_CHECK([./calc input], 0, [], [stderr])])
m4_bmatch([$1], [--debug],
[AT_CHECK([wc -l <stderr | sed 's/[[^0-9]]//g'], 0, [$3
m4_bmatch([$1],
[%debug.*%glr\|%glr.*%debug],
[],
[%debug],
[AT_CHECK([wc -l <stderr | sed 's/[[^0-9]]//g'], 0, [$3
])])
# Normalize the observed and expected error messages, depending upon the
@@ -332,6 +337,7 @@ m4_bmatch([$1], [--debug],
# 1. Remove the traces from observed.
sed '/^Starting/d
/^Entering/d
/^Stack/d
/^Reading/d
/^Reducing/d
/^Shifting/d
@@ -350,7 +356,7 @@ m4_bmatch([$1], [--location], [],
[[sed 's/^[-0-9.]*: //' expout >at-expout
mv at-expout expout]])
# 4. If error-verbose is not used, strip the`, unexpected....' part.
m4_bmatch([$1], [--yyerror-verbose], [],
m4_bmatch([$1], [%error-verbose], [],
[[sed 's/parse error, .*$/parse error/' expout >at-expout
mv at-expout expout]])
# 5. Check
@@ -358,8 +364,8 @@ AT_CHECK([cat stderr], 0, [expout])
])
# AT_CHECK_CALC([BISON-OPTIONS], [PARSER-EXPECTED-STDERR])
# --------------------------------------------------------
# AT_CHECK_CALC([BISON-OPTIONS])
# ------------------------------
# Start a testing chunk which compiles `calc' grammar with
# BISON-OPTIONS, and performs several tests over the parser.
m4_define([AT_CHECK_CALC],
@@ -369,7 +375,7 @@ AT_SETUP([Calculator $1])
AT_DATA_CALC_Y([$1])
# Specify the output files to avoid problems on different file systems.
AT_CHECK([bison calc.y -o calc.c m4_bpatsubst([$1], [--yyerror-verbose])],
AT_CHECK([bison calc.y -o calc.c m4_bpatsubst([$1], [%[^ ]*])],
[0], [], [])
AT_COMPILE([calc])
@@ -427,22 +433,62 @@ AT_CLEANUP
# ------------------ #
# Test the parsers. #
# ------------------ #
# ------------------------ #
# Simple LALR Calculator. #
# ------------------------ #
AT_CHECK_CALC()
AT_BANNER([[Simple LALR Calculator.]])
AT_CHECK_CALC([--defines])
AT_CHECK_CALC([--locations])
AT_CHECK_CALC([--name-prefix=calc])
AT_CHECK_CALC([--verbose])
AT_CHECK_CALC([--yacc])
AT_CHECK_CALC([--yyerror-verbose])
# AT_CHECK_CALC_LALR([BISON-OPTIONS])
# -----------------------------------
# Start a testing chunk which compiles `calc' grammar with
# BISON-OPTIONS, and performs several tests over the parser.
m4_define([AT_CHECK_CALC_LALR],
[AT_CHECK_CALC($@)])
AT_CHECK_CALC([--locations --yyerror-verbose])
AT_CHECK_CALC_LALR()
AT_CHECK_CALC([--defines --locations --name-prefix=calc --verbose --yacc --yyerror-verbose])
AT_CHECK_CALC_LALR([--defines])
AT_CHECK_CALC_LALR([--locations])
AT_CHECK_CALC_LALR([--name-prefix=calc])
AT_CHECK_CALC_LALR([--verbose])
AT_CHECK_CALC_LALR([--yacc])
AT_CHECK_CALC_LALR([%error-verbose])
AT_CHECK_CALC([--debug])
AT_CHECK_CALC([--debug --defines --locations --name-prefix=calc --verbose --yacc --yyerror-verbose])
AT_CHECK_CALC_LALR([%error-verbose --locations])
AT_CHECK_CALC_LALR([%error-verbose --defines --locations --name-prefix=calc --verbose --yacc])
AT_CHECK_CALC_LALR([%debug])
AT_CHECK_CALC_LALR([%error-verbose %debug --defines --locations --name-prefix=calc --verbose --yacc])
# ----------------------- #
# Simple GLR Calculator. #
# ----------------------- #
AT_BANNER([[Simple GLR Calculator.]])
# AT_CHECK_CALC_GLR([BISON-OPTIONS])
# ----------------------------------
# Start a testing chunk which compiles `calc' grammar with
# BISON-OPTIONS and %glr-parser, and performs several tests over the parser.
m4_define([AT_CHECK_CALC_GLR],
[AT_CHECK_CALC([%glr_parser] $@)])
AT_CHECK_CALC_GLR()
AT_CHECK_CALC_GLR([--defines])
AT_CHECK_CALC_GLR([--locations])
AT_CHECK_CALC_GLR([--name-prefix=calc])
AT_CHECK_CALC_GLR([--verbose])
AT_CHECK_CALC_GLR([--yacc])
AT_CHECK_CALC_GLR([%error-verbose])
AT_CHECK_CALC_GLR([%error-verbose --locations])
AT_CHECK_CALC_GLR([%error-verbose --defines --locations --name-prefix=calc --verbose --yacc])
AT_CHECK_CALC_GLR([%debug])
AT_CHECK_CALC_GLR([%error-verbose %debug --defines --locations --name-prefix=calc --verbose --yacc])