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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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70
data/skeletons/lalr1.d
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@@ -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