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style: avoid explicit symbol numbers

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This should have been part of commit "symbols: stop dealing with YYEMPTY
as b4_symbol(-2, ...)" (cd40ec9526).
Give names to all the special symbols: "eof", "error" and "undef".

* data/skeletons/bison.m4 (b4_symbol): Let `b4_symbol(eof, ...)` mean
`b4_symbol(0, ...)`, `b4_symbol(error, ...)` mean `b4_symbol(1, ...)`,
and , `b4_symbol(undef, ...)` mean `b4_symbol(2, ...)`..

* data/skeletons/c.m4, data/skeletons/glr.c, data/skeletons/glr.cc,
* data/skeletons/glr2.cc, data/skeletons/lalr1.cc,
* data/skeletons/lalr1.d, data/skeletons/lalr1.java,
* data/skeletons/yacc.c:
Prefer symbols to numbers.
This commit is contained in:
Akim Demaille
2020-11-07 16:21:00 +01:00
parent 34e6e8815a
commit 5a31cda4c3
10 changed files with 82 additions and 75 deletions
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20
data/skeletons/lalr1.d
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@@ -480,14 +480,14 @@ 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 (yytoken == ]b4_symbol(1, kind)[)
if (yytoken == ]b4_symbol(error, kind)[)
{
// 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.]b4_symbol(2, id)[;
yytoken = ]b4_symbol(2, kind)[;]b4_locations_if([[
yychar = TokenKind.]b4_symbol(undef, id)[;
yytoken = ]b4_symbol(undef, kind)[;]b4_locations_if([[
yyerrloc = yylloc;]])[
label = YYERRLAB1;
}
@@ -569,10 +569,10 @@ m4_popdef([b4_at_dollar])])dnl
/* If just tried and failed to reuse lookahead token after an
* error, discard it. */
if (yychar <= TokenKind.]b4_symbol(0, [id])[)
if (yychar <= TokenKind.]b4_symbol(eof, [id])[)
{
/* Return failure if at end of input. */
if (yychar == TokenKind.]b4_symbol(0, [id])[)
if (yychar == TokenKind.]b4_symbol(eof, [id])[)
return false;
}
else
@@ -609,8 +609,8 @@ m4_popdef([b4_at_dollar])])dnl
yyn = yypact_[yystate];
if (!yyPactValueIsDefault(yyn))
{
yyn += ]b4_symbol(1, kind)[;
if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == ]b4_symbol(1, kind)[)
yyn += ]b4_symbol(error, kind)[;
if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == ]b4_symbol(error, kind)[)
{
yyn = yytable_[yyn];
if (0 < yyn)
@@ -772,7 +772,7 @@ m4_popdef([b4_at_dollar])])dnl
int yychecklim = yylast_ - yyn + 1;
int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
if (yycheck_[yyx + yyn] == yyx && yyx != ]b4_symbol(1, kind)[
if (yycheck_[yyx + yyn] == yyx && yyx != ]b4_symbol(error, kind)[
&& !yyTableValueIsError(yytable_[yyx + yyn]))
{
if (yyarg is null)
@@ -861,11 +861,11 @@ m4_popdef([b4_at_dollar])])dnl
immutable int code_max = ]b4_code_max[;
if (t <= 0)
return ]b4_symbol(0, kind)[;
return ]b4_symbol(eof, kind)[;
else if (t <= code_max)
return SymbolKind(translate_table[t]);
else
return ]b4_symbol(2, kind)[;]])[
return ]b4_symbol(undef, kind)[;]])[
}
private static immutable int yylast_ = ]b4_last[;