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java: make yysyntaxErrorArguments a private detail

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* data/skeletons/lalr1.java (yysyntaxErrorArguments): Move it from the
context, to the parser object.
Generate only for detailed and verbose error messages.
* tests/local.at (AT_YYERROR_DEFINE(java)): Use yyexpectedTokens
instead.
This commit is contained in:
Akim Demaille
2020-03-26 08:35:50 +01:00
parent ee56b6e0f2
commit b7045aa706
2 changed files with 59 additions and 49 deletions
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81
data/skeletons/lalr1.java
View File

@@ -933,46 +933,49 @@ b4_dollar_popdef[]dnl
{
return ]b4_parser_class[.yysymbolName (yysymbol);
}
int yysyntaxErrorArguments (int[] yyarg, int yyargn)
{
/* There are many possibilities here to consider:
- If this state is a consistent state with a default action,
then the only way this function was invoked is if the
default action is an error action. In that case, don't
check for expected tokens because there are none.
- The only way there can be no lookahead present (in tok) is
if this state is a consistent state with a default action.
Thus, detecting the absence of a lookahead is sufficient to
determine that there is no unexpected or expected token to
report. In that case, just report a simple "syntax error".
- Don't assume there isn't a lookahead just because this
state is a consistent state with a default action. There
might have been a previous inconsistent state, consistent
state with a non-default action, or user semantic action
that manipulated yychar. (However, yychar is currently out
of scope during semantic actions.)
- Of course, the expected token list depends on states to
have correct lookahead information, and it depends on the
parser not to perform extra reductions after fetching a
lookahead from the scanner and before detecting a syntax
error. Thus, state merging (from LALR or IELR) and default
reductions corrupt the expected token list. However, the
list is correct for canonical LR with one exception: it
will still contain any token that will not be accepted due
to an error action in a later state.
*/
int yycount = 0;
if (this.yytoken != yyempty_)
{
yyarg[yycount++] = this.yytoken;
yycount += this.yyexpectedTokens (yyarg, 1, yyargn);
}
return yycount;
}
}
/**
]b4_parse_error_bmatch(
[detailed\|verbose], [[
private int yysyntaxErrorArguments (Context yyctx, int[] yyarg, int yyargn)
{
/* There are many possibilities here to consider:
- If this state is a consistent state with a default action,
then the only way this function was invoked is if the
default action is an error action. In that case, don't
check for expected tokens because there are none.
- The only way there can be no lookahead present (in tok) is
if this state is a consistent state with a default action.
Thus, detecting the absence of a lookahead is sufficient to
determine that there is no unexpected or expected token to
report. In that case, just report a simple "syntax error".
- Don't assume there isn't a lookahead just because this
state is a consistent state with a default action. There
might have been a previous inconsistent state, consistent
state with a non-default action, or user semantic action
that manipulated yychar. (However, yychar is currently out
of scope during semantic actions.)
- Of course, the expected token list depends on states to
have correct lookahead information, and it depends on the
parser not to perform extra reductions after fetching a
lookahead from the scanner and before detecting a syntax
error. Thus, state merging (from LALR or IELR) and default
reductions corrupt the expected token list. However, the
list is correct for canonical LR with one exception: it
will still contain any token that will not be accepted due
to an error action in a later state.
*/
int yycount = 0;
if (yyctx.getToken () != yyempty_)
{
yyarg[yycount++] = yyctx.getToken ();
yycount += yyctx.yyexpectedTokens (yyarg, 1, yyargn);
}
return yycount;
}
]])[
/**
* Report a syntax error.
*/
private void yyreportSyntaxError (Context yyctx)
@@ -984,7 +987,7 @@ b4_dollar_popdef[]dnl
{
final int argmax = 5;
int[] yyarg = new int[argmax];
int yycount = yyctx.yysyntaxErrorArguments (yyarg, argmax);
int yycount = yysyntaxErrorArguments (yyctx, yyarg, argmax);
String[] yystr = new String[yycount];
for (int yyi = 0; yyi < yycount; ++yyi)
yystr[yyi] = yysymbolName (yyarg[yyi]);

27
tests/local.at
View File

@@ -972,17 +972,24 @@ m4_define([AT_YYERROR_DEFINE(java)],
]AT_ERROR_CUSTOM_IF([[
public void yyreportSyntaxError (Calc.Context ctx)
{
int[] arg = new int[ctx.NTOKENS];
int n = ctx.yysyntaxErrorArguments (arg, ctx.NTOKENS);
System.err.print (]AT_LOCATION_IF([[ctx.getLocation () + ": "]]
+ )["syntax error on token @<:@" + ctx.yysymbolName (arg[0]) + "@:>@");
if (1 < n)
{
System.err.print (" (expected:");
for (int i = 1; i < n; ++i)
System.err.print (" @<:@" + ctx.yysymbolName (arg[i]) + "@:>@");
System.err.print (")");
}
+ )["syntax error");
{
int token = ctx.getToken ();
if (token != ctx.EMPTY)
System.err.print (" on token @<:@" + ctx.yysymbolName (token) + "@:>@");
}
{
int[] arg = new int[ctx.NTOKENS];
int n = ctx.yyexpectedTokens (arg, ctx.NTOKENS);
if (0 < n)
{
System.err.print (" (expected:");
for (int i = 0; i < n; ++i)
System.err.print (" @<:@" + ctx.yysymbolName (arg[i]) + "@:>@");
System.err.print (")");
}
}
System.err.println ("");
}
]])