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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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28
data/skeletons/lalr1.java
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@@ -199,8 +199,8 @@ import java.util.ArrayList;
*/
public interface Lexer {
]b4_token_enums[
/** Deprecated, use ]b4_symbol(0, id)[ instead. */
public static final int EOF = ]b4_symbol(0, id)[;
/** Deprecated, use ]b4_symbol(eof, id)[ instead. */
public static final int EOF = ]b4_symbol(eof, id)[;
]b4_pull_if([b4_locations_if([[
/**
* Method to retrieve the beginning position of the last scanned token.
@@ -643,14 +643,14 @@ b4_dollar_popdef[]dnl
yySymbolPrint("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 = Lexer.]b4_symbol(2, id)[;
yytoken = ]b4_symbol(2, kind)[;]b4_locations_if([[
yychar = Lexer.]b4_symbol(undef, id)[;
yytoken = ]b4_symbol(undef, kind)[;]b4_locations_if([[
yyerrloc = yylloc;]])[
label = YYERRLAB1;
}
@@ -740,10 +740,10 @@ b4_dollar_popdef[]dnl
/* If just tried and failed to reuse lookahead token after an
error, discard it. */
if (yychar <= Lexer.]b4_symbol(0, id)[)
if (yychar <= Lexer.]b4_symbol(eof, id)[)
{
/* Return failure if at end of input. */
if (yychar == Lexer.]b4_symbol(0, id)[)
if (yychar == Lexer.]b4_symbol(eof, id)[)
]b4_push_if([{label = YYABORT; break;}], [return false;])[
}
else
@@ -780,9 +780,9 @@ b4_dollar_popdef[]dnl
yyn = yypact_[yystate];
if (!yyPactValueIsDefault (yyn))
{
yyn += ]b4_symbol(1, kind)[.getCode();
yyn += ]b4_symbol(error, kind)[.getCode();
if (0 <= yyn && yyn <= YYLAST_
&& yycheck_[yyn] == ]b4_symbol(1, kind)[.getCode())
&& yycheck_[yyn] == ]b4_symbol(error, kind)[.getCode())
{
yyn = yytable_[yyn];
if (0 < yyn)
@@ -964,8 +964,8 @@ b4_dollar_popdef[]dnl
for (int yyx = 0; yyx < YYNTOKENS_; ++yyx)
{
SymbolKind yysym = SymbolKind.get(yyx);
if (yysym != ]b4_symbol(1, kind)[
&& yysym != ]b4_symbol(2, kind)[
if (yysym != ]b4_symbol(error, kind)[
&& yysym != ]b4_symbol(undef, kind)[
&& yyparser.yylacCheck(yystack, yysym))
{
if (yyarg == null)
@@ -988,7 +988,7 @@ b4_dollar_popdef[]dnl
int yychecklim = YYLAST_ - yyn + 1;
int yyxend = yychecklim < NTOKENS ? yychecklim : NTOKENS;
for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
if (yycheck_[yyx + yyn] == yyx && yyx != ]b4_symbol(1, kind)[.getCode()
if (yycheck_[yyx + yyn] == yyx && yyx != ]b4_symbol(error, kind)[.getCode()
&& !yyTableValueIsError(yytable_[yyx + yyn]))
{
if (yyarg == null)
@@ -1282,11 +1282,11 @@ b4_dollar_popdef[]dnl
// Last valid token kind.
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.get(yytranslate_table_[t]);
else
return ]b4_symbol(2, kind)[;
return ]b4_symbol(undef, kind)[;
}
]b4_integral_parser_table_define([translate_table], [b4_translate])[
]])[