Future/bison
1
0
Fork 0
mirror of https://git.savannah.gnu.org/git/bison.git synced 2026-03-09 12:23:04 +00:00
Code Issues Packages Projects Releases Wiki Activity

Fuse yyval and yyloc into yylhs.

Browse Source 
* data/lalr1.cc (b4_lhs_value, b4_lhs_location): Adjust to using
	yylhs.
	(parse): Replace yyval and yyloc with yylhs.value and
	yylhs.location.
	After a user action, compute yylhs.state earlier.
	(yyerrlab1): Do not play tricks with yylhs.location, rather, use a
	fresh error_token.
This commit is contained in:
Akim Demaille
2008-07-31 11:57:45 +02:00
parent 2935744b3a
commit e1f93869da
2 changed files with 84 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

131
data/lalr1.cc
View File

@@ -46,6 +46,20 @@ m4_define([b4_assert_if],
[b4_percent_define_ifdef([[assert]], [$1], [$2])])
# b4_lhs_value([TYPE])
# --------------------
# Expansion of $<TYPE>$.
m4_define([b4_lhs_value],
[b4_symbol_value([yylhs.value], [$1])])
# b4_lhs_location()
# -----------------
# Expansion of @$.
m4_define([b4_lhs_location],
[yylhs.location])
# b4_rhs_value(RULE-LENGTH, NUM, [TYPE])
# --------------------------------------
# Expansion of $<TYPE>NUM, where the current rule has RULE-LENGTH
@@ -797,11 +811,10 @@ b4_percent_code_get[]dnl
/// The locations where the error started and ended.
data_type yyerror_range[2];
/// $$.
semantic_type yyval;
/// @@$.
location_type yyloc;
/// $$ and @@$.
data_type yylhs;
/// The return value of parse().
int yyresult;
YYCDEBUG << "Starting parse" << std::endl;
@@ -910,22 +923,22 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
/* Variants are always initialized to an empty instance of the
correct type. The default $$=$1 rule is NOT applied when using
variants */
]b4_symbol_variant([[yyr1_@{yyn@}]], [yyval], [build])[],[
]b4_symbol_variant([[yyr1_@{yyn@}]], [yylhs.value], [build])[],[
/* If YYLEN is nonzero, implement the default value of the action:
`$$ = $1'. Otherwise, use the top of the stack.
Otherwise, the following line sets YYVAL to garbage.
Otherwise, the following line sets YYLHS.VALUE to garbage.
This behavior is undocumented and Bison
users should not rely upon it. */
if (yylen)
yyval = yystack_@{yylen - 1@}.value;
yylhs.value = yystack_@{yylen - 1@}.value;
else
yyval = yystack_@{0@}.value;])[
yylhs.value = yystack_@{0@}.value;])[
// Compute the default @@$.
{
slice<data_type, stack_type> slice (yystack_, yylen);
YYLLOC_DEFAULT (yyloc, slice, yylen);
YYLLOC_DEFAULT (yylhs.location, slice, yylen);
}
// Perform the reduction.
@@ -936,18 +949,27 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
default:
break;
}
YY_SYMBOL_PRINT ("-> $$ =", yyr1_[yyn], yyval, yyloc);
// Compute post-reduction state.
yyn = yyr1_[yyn];
yystate = yypgoto_[yyn - yyntokens_] + yystack_[yylen].state;
if (0 <= yystate && yystate <= yylast_
&& yycheck_[yystate] == yystack_[yylen].state)
yystate = yytable_[yystate];
else
yystate = yydefgoto_[yyn - yyntokens_];
yylhs.state = yystate;
YY_SYMBOL_PRINT ("-> $$ =", yyn, yylhs.value, yylhs.location);
]b4_variant_if([[
// Destroy the lhs symbols.
for (int i = 0; i < yylen; ++i)
// Destroy a variant which value may have be swapped with yyval.
// The value of yyval (hence maybe one of these lhs symbols)
// depends on what does the default contruction for this type.
// In the case of pointers for instance, nothing is done, so the
// value is junk. Therefore do not try to report the content in
// the debug trace, it's junk. Hence yymsg = 0. Besides, that
// keeps exactly the same traces as with the other Bison
// skeletons.
// Destroy a variant which value may have be swapped with
// yylhs.value. The value of yylhs.value (hence maybe one of
// these lhs symbols) depends on what does the default
// contruction for this type. In the case of pointers for
// instance, nothing is done, so the value is junk. Therefore
// do not try to report the content in the debug trace, it's
// junk. Hence yymsg = 0. Besides, that keeps exactly the same
// traces as with the other Bison skeletons.
yydestruct_ (0,
yystos_[yystack_[i].state],
yystack_[i].value, yystack_[i].location);]])[
@@ -957,14 +979,7 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
YY_STACK_PRINT ();
/* Shift the result of the reduction. */
yyn = yyr1_[yyn];
yystate = yypgoto_[yyn - yyntokens_] + yystack_[0].state;
if (0 <= yystate && yystate <= yylast_
&& yycheck_[yystate] == yystack_[0].state)
yystate = yytable_[yystate];
else
yystate = yydefgoto_[yyn - yyntokens_];
yypush_ (0, yystate, yyval, yyloc);
yypush_ (0, yylhs.state, yylhs.value, yylhs.location);
goto yynewstate;
/*------------------------------------.
@@ -1026,42 +1041,42 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
`-------------------------------------------------------------*/
yyerrlab1:
yyerrstatus_ = 3; /* Each real token shifted decrements this. */
{
data_type error_token;
for (;;)
{
yyn = yypact_[yystate];
if (yyn != yypact_ninf_)
{
yyn += yyterror_;
if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yyterror_)
{
yyn = yytable_[yyn];
if (0 < yyn)
break;
}
}
for (;;)
{
yyn = yypact_[yystate];
if (yyn != yypact_ninf_)
{
yyn += yyterror_;
if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yyterror_)
{
yyn = yytable_[yyn];
if (0 < yyn)
break;
}
}
// Pop the current state because it cannot handle the error token.
if (yystack_.size () == 1)
YYABORT;
// Pop the current state because it cannot handle the error token.
if (yystack_.size () == 1)
YYABORT;
yyerror_range[0].location = yystack_[0].location;
yydestruct_ ("Error: popping",
yystos_[yystate],
yystack_[0].value, yystack_[0].location);
yypop_ ();
yystate = yystack_[0].state;
YY_STACK_PRINT ();
}
yyerror_range[0].location = yystack_[0].location;
yydestruct_ ("Error: popping",
yystos_[yystate],
yystack_[0].value, yystack_[0].location);
yypop_ ();
yystate = yystack_[0].state;
YY_STACK_PRINT ();
}
yyerror_range[1].location = yylloc;
YYLLOC_DEFAULT (error_token.location, (yyerror_range - 1), 2);
yyerror_range[1].location = yylloc;
// Using YYLLOC is tempting, but would change the location of
// the lookahead. YYLOC is available though.
YYLLOC_DEFAULT (yyloc, (yyerror_range - 1), 2);
/* Shift the error token. */
yystate = yyn;
yypush_ ("Shifting", yystate, yylval, yyloc);
/* Shift the error token. */
yystate = yyn;
yypush_ ("Shifting", yystate, error_token.value, error_token.location);
}
goto yynewstate;
/* Accept. */