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all: don't emit an error message when the scanner returns YYERRCODE

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I'm quite pleased to see that the tricky case of glr.c was already
prepared by the changes to support syntax_error exceptions.  Better
yet, it is actually syntax_error that becomes a special case of the
general pattern: make yytoken be YYERRCODE.

* data/skeletons/glr.c (YYFAULTYTOK): Remove the now useless (Basil)
Faulty token.
Instead, use the error token.
* data/skeletons/lalr1.d, data/skeletons/lalr1.java: When computing
the action, first check the case of the error token.

* tests/calc.at: Check cases for the error token symbols before and
after it.
This commit is contained in:
Akim Demaille
2020-04-26 14:48:59 +02:00
parent 58e79539fc
commit b254b36db8
6 changed files with 121 additions and 76 deletions
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28
data/skeletons/glr.c
View File

@@ -334,10 +334,7 @@ static YYLTYPE yyloc_default][]b4_yyloc_default;])[
#define YYMAXLEFT ]b4_max_left_semantic_context[
/* YYMAXUTOK -- Last valid token number (for yychar). */
#define YYMAXUTOK ]b4_user_token_number_max[]b4_glr_cc_if([[
/* YYFAULTYTOK -- Token number (for yychar) that denotes a
syntax_error thrown from the scanner. */
#define YYFAULTYTOK (YYMAXUTOK + 1)]])[
#define YYMAXUTOK ]b4_user_token_number_max[
/* YYTRANSLATE(TOKEN-NUM) -- Symbol number corresponding to TOKEN-NUM
as returned by yylex, with out-of-bounds checking. */
@@ -830,7 +827,7 @@ yygetToken (int *yycharp][]b4_pure_if([, yyGLRStack* yystackp])[]b4_user_formals
// Map errors caught in the scanner to the undefined token,
// so that error handling is started. However, record this
// with this special value of yychar.
*yycharp = YYFAULTYTOK;
*yycharp = ]b4_symbol(1, id)[;
}
#endif // YY_EXCEPTIONS]], [[
*yycharp = ]b4_lex[;]])[
@@ -1035,8 +1032,14 @@ static inline int
yygetLRActions (yy_state_t yystate, yysymbol_kind_t yytoken, const short** yyconflicts)
{
int yyindex = yypact[yystate] + yytoken;
if (yyisDefaultedState (yystate)
|| yyindex < 0 || YYLAST < yyindex || yycheck[yyindex] != yytoken)
if (yytoken == ]b4_symbol(1, kind)[)
{
// This is the error token.
*yyconflicts = yyconfl;
return 0;
}
else if (yyisDefaultedState (yystate)
|| yyindex < 0 || YYLAST < yyindex || yycheck[yyindex] != yytoken)
{
*yyconflicts = yyconfl;
return -yydefact[yystate];
@@ -2486,12 +2489,11 @@ b4_dollar_popdef])[]dnl
}
else if (yyisErrorAction (yyaction))
{]b4_locations_if([[
yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[]b4_glr_cc_if([[
/* Don't issue an error message again for exceptions
thrown from the scanner. */
if (yychar != YYFAULTYTOK)
]], [[
]])[ yyreportSyntaxError (&yystack]b4_user_args[);
yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[
/* Issue an error message unless the scanner already
did. */
if (yychar != ]b4_symbol(1, id)[)
yyreportSyntaxError (&yystack]b4_user_args[);
goto yyuser_error;
}
else

2
data/skeletons/glr.cc
View File

@@ -344,6 +344,8 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
#define ]b4_symbol(-2, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(-2, [id])[
#undef ]b4_symbol(0, [id])[
#define ]b4_symbol(0, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(0, [id])[
#undef ]b4_symbol(1, [id])[
#define ]b4_symbol(1, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(1, [id])[
#ifndef ]b4_api_PREFIX[STYPE
# define ]b4_api_PREFIX[STYPE ]b4_namespace_ref[::]b4_parser_class[::semantic_type

70
data/skeletons/lalr1.d
View File

@@ -509,39 +509,53 @@ m4_popdef([b4_at_dollar])])dnl
yytoken = yytranslate_ (yychar);]b4_parse_trace_if([[
yy_symbol_print ("Next token is", yytoken, yylval]b4_locations_if([, yylloc])[);]])[
/* If the proper action on seeing token YYTOKEN is to reduce or to
detect an error, take that action. */
yyn += yytoken;
if (yyn < 0 || yylast_ < yyn || yycheck_[yyn] != yytoken)
label = YYDEFAULT;
/* <= 0 means reduce or error. */
else if ((yyn = yytable_[yyn]) <= 0)
if (yytoken == SymbolKind.]b4_symbol(1, kind)[)
{
if (yy_table_value_is_error_ (yyn))
label = YYERRLAB;
else
{
yyn = -yyn;
label = YYREDUCE;
}
// The scanner already issued an error message, process directly
// to error recovery. But do not keep the error token as
// lookahead, it is too special and may lead us to an endless
// loop in error recovery. */
yychar = TokenKind.YYUNDEF;
yytoken = SymbolKind.]b4_symbol_prefix[YYUNDEF;]b4_locations_if([[
yyerrloc = yylloc;]])[
label = YYERRLAB1;
}
else
{
/* Shift the lookahead token. */]b4_parse_trace_if([[
yy_symbol_print ("Shifting", yytoken, yylval]b4_locations_if([, yylloc])[);]])[
/* If the proper action on seeing token YYTOKEN is to reduce or to
detect an error, take that action. */
yyn += yytoken;
if (yyn < 0 || yylast_ < yyn || yycheck_[yyn] != yytoken)
label = YYDEFAULT;
/* Discard the token being shifted. */
yychar = TokenKind.YYEMPTY;
/* <= 0 means reduce or error. */
else if ((yyn = yytable_[yyn]) <= 0)
{
if (yy_table_value_is_error_ (yyn))
label = YYERRLAB;
else
{
yyn = -yyn;
label = YYREDUCE;
}
}
else
{
/* Shift the lookahead token. */]b4_parse_trace_if([[
yy_symbol_print ("Shifting", yytoken, yylval]b4_locations_if([, yylloc])[);]])[
/* Count tokens shifted since error; after three, turn off error
* status. */
if (yyerrstatus_ > 0)
--yyerrstatus_;
/* Discard the token being shifted. */
yychar = TokenKind.YYEMPTY;
yystate = yyn;
yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
label = YYNEWSTATE;
/* Count tokens shifted since error; after three, turn off error
* status. */
if (yyerrstatus_ > 0)
--yyerrstatus_;
yystate = yyn;
yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
label = YYNEWSTATE;
}
}
break;
@@ -577,8 +591,8 @@ m4_popdef([b4_at_dollar])])dnl
yytoken = SymbolKind.]b4_symbol(-2, kind)[;
yyerror (]b4_locations_if([yylloc, ])[yysyntax_error (yystate, yytoken));
}
]b4_locations_if([ yyerrloc = yylloc;])[
]b4_locations_if([
yyerrloc = yylloc;])[
if (yyerrstatus_ == 3)
{
/* If just tried and failed to reuse lookahead token after an

77
data/skeletons/lalr1.java
View File

@@ -164,12 +164,12 @@ import java.text.MessageFormat;
}
}
private ]b4_location_type[ yylloc (YYStack rhs, int n)
private ]b4_location_type[ yylloc(YYStack rhs, int n)
{
if (0 < n)
return new ]b4_location_type[ (rhs.locationAt (n-1).begin, rhs.locationAt (0).end);
return new ]b4_location_type[(rhs.locationAt(n-1).begin, rhs.locationAt(0).end);
else
return new ]b4_location_type[ (rhs.locationAt (0).end);
return new ]b4_location_type[(rhs.locationAt(0).end);
}]])[
]b4_declare_symbol_enum[
@@ -615,41 +615,55 @@ b4_dollar_popdef[]dnl
yySymbolPrint ("Next token is", yytoken,
yylval]b4_locations_if([, yylloc])[);]])[
/* If the proper action on seeing token YYTOKEN is to reduce or to
detect an error, take that action. */
yyn += yytoken.getCode ();
if (yyn < 0 || YYLAST_ < yyn || yycheck_[yyn] != yytoken.getCode ())
label = YYDEFAULT;
/* <= 0 means reduce or error. */
else if ((yyn = yytable_[yyn]) <= 0)
if (yytoken == SymbolKind.]b4_symbol_prefix[YYERRCODE)
{
if (yyTableValueIsError (yyn))
label = YYERRLAB;
else
{
yyn = -yyn;
label = YYREDUCE;
}
// The scanner already issued an error message, process directly
// to error recovery. But do not keep the error token as
// lookahead, it is too special and may lead us to an endless
// loop in error recovery. */
yychar = Lexer.]b4_percent_define_get([api.token.prefix])[YYUNDEF;
yytoken = SymbolKind.]b4_symbol_prefix[YYUNDEF;]b4_locations_if([[
yyerrloc = yylloc;]])[
label = YYERRLAB1;
}
else
{
/* Shift the lookahead token. */]b4_parse_trace_if([[
yySymbolPrint ("Shifting", yytoken,
yylval]b4_locations_if([, yylloc])[);
/* If the proper action on seeing token YYTOKEN is to reduce or to
detect an error, take that action. */
yyn += yytoken.getCode ();
if (yyn < 0 || YYLAST_ < yyn || yycheck_[yyn] != yytoken.getCode ())
label = YYDEFAULT;
/* <= 0 means reduce or error. */
else if ((yyn = yytable_[yyn]) <= 0)
{
if (yyTableValueIsError (yyn))
label = YYERRLAB;
else
{
yyn = -yyn;
label = YYREDUCE;
}
}
else
{
/* Shift the lookahead token. */]b4_parse_trace_if([[
yySymbolPrint ("Shifting", yytoken,
yylval]b4_locations_if([, yylloc])[);
]])[
/* Discard the token being shifted. */
yychar = YYEMPTY_;
/* Discard the token being shifted. */
yychar = YYEMPTY_;
/* Count tokens shifted since error; after three, turn off error
status. */
if (yyerrstatus_ > 0)
--yyerrstatus_;
/* Count tokens shifted since error; after three, turn off error
status. */
if (yyerrstatus_ > 0)
--yyerrstatus_;
yystate = yyn;
yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
label = YYNEWSTATE;
yystate = yyn;
yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
label = YYNEWSTATE;
}
}
break;
@@ -685,7 +699,6 @@ b4_dollar_popdef[]dnl
yytoken = null;
yyreportSyntaxError (new Context (yystack, yytoken]b4_locations_if([[, yylloc]])[));
}
]b4_locations_if([[
yyerrloc = yylloc;]])[
if (yyerrstatus_ == 3)

5
data/skeletons/yacc.c
View File

@@ -1963,9 +1963,8 @@ yyerrlab:
goto yyexhaustedlab;
}]])[
}
]b4_locations_if([[ yyerror_range[1] = yylloc;]])[
]b4_locations_if([[
yyerror_range[1] = yylloc;]])[
if (yyerrstatus == 3)
{
/* If just tried and failed to reuse lookahead token after an

15
tests/calc.at
View File

@@ -1036,6 +1036,21 @@ _AT_CHECK_CALC_ERROR([$1], [0], [(#) + (#) = 2222],
[[1.2: syntax error: invalid character: '#'
1.8: syntax error: invalid character: '#']])
_AT_CHECK_CALC_ERROR([$1], [0], [(1 + #) = 1111],
[[final: 1111 0 0]],
[102],
[[1.6: syntax error: invalid character: '#']])
_AT_CHECK_CALC_ERROR([$1], [0], [(# + 1) = 1111],
[[final: 1111 0 0]],
[102],
[[1.2: syntax error: invalid character: '#']])
_AT_CHECK_CALC_ERROR([$1], [0], [(1 + # + 1) = 1111],
[[final: 1111 0 0]],
[102],
[[1.6: syntax error: invalid character: '#']])
AT_BISON_OPTION_POPDEFS