Akim Demaille 84b1972c96 yacc.c: use negative numbers for errors in auxiliary functions ...

yyparse returns 0, 1, 2 since ages (accept, reject, memory exhausted).
Some of our auxiliary functions such as yy_lac and
yyreport_syntax_error also need to return error codes and also use 0,
1, 2.  Because it uses yy_lac, yyexpected_tokens also needs to return
"problem", "memory exhausted", but in case of success, it needs to
return the number of tokens, so it cannot use 1 and 2 as error code.
Currently it uses -1 and -2, which is later converted into 1 and 2 as
yacc.c expects it.

Let's simplify this and use consistently -1 and -2 for auxiliary
functions that are not exposed (or not yet exposed) to the user.  In
particular this will save the user from having to convert
yyexpected_tokens's -2 into yyreport_syntax_error's 2: both return -1
or -2.

* data/skeletons/yacc.c (yy_lac, yyreport_syntax_error)
(yy_lac_stack_realloc): Return -1, -2 for errors instead of 1, 2.
Adjust callers.
* examples/c/bistromathic/parse.y (yyreport_syntax_error): Do take
error codes into account.
Issue a syntax error message even if we ran out of memory.
* src/parse-gram.y, tests/local.at (yyreport_syntax_error): Adjust.

2020-03-23 07:02:36 +01:00

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