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parser: improve the error message for symbol class redefinition

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Currently our error messages include both "symbol redeclared" and
"symbol redefined", and they mean something different.  This is
obscure, let's make this clearer.

I think the idea between 'definition' vs. 'declaration' is that in the
case of the nonterminals, the actual definition is its set of rules,
so %nterm would be about declaration.  The case of %token is less
clear.

* src/symtab.c (complain_class_redefined): New.
(symbol_class_set): Use it.
Simplify the logic of this function to clearly skip its body when the
preconditions are not met.
* tests/input.at (Symbol class redefinition): New.
This commit is contained in:
Akim Demaille
2018-12-09 08:14:35 +01:00
parent afdefecab6
commit 20b0746793
3 changed files with 74 additions and 18 deletions
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48
src/symtab.c
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@@ -302,6 +302,19 @@ semantic_type_redeclaration (semantic_type *s, const char *what, location first,
_("previous declaration"));
}
static void
complain_class_redeclared (symbol *sym, symbol_class class, location second)
{
unsigned i = 0;
complain_indent (&second, complaint, &i,
class == token_sym
? _("symbol %s redeclared as a token")
: _("symbol %s redeclared as a nonterminal"), sym->tag);
i += SUB_INDENT;
complain_indent (&sym->location, complaint, &i,
_("previous definition"));
}
void
symbol_location_as_lhs_set (symbol *sym, location loc)
@@ -430,27 +443,26 @@ symbol_precedence_set (symbol *sym, int prec, assoc a, location loc)
void
symbol_class_set (symbol *sym, symbol_class class, location loc, bool declaring)
{
bool warned = false;
if (sym->content->class != unknown_sym && sym->content->class != class)
aver (class != unknown_sym);
sym_content *s = sym->content;
if (s->class != unknown_sym && s->class != class)
complain_class_redeclared (sym, class, loc);
else
{
complain (&loc, complaint, _("symbol %s redefined"), sym->tag);
/* Don't report both "redefined" and "redeclared". */
warned = true;
}
s->class = class;
if (class == nterm_sym && sym->content->class != nterm_sym)
sym->content->number = nvars++;
else if (class == token_sym && sym->content->number == NUMBER_UNDEFINED)
sym->content->number = ntokens++;
if (class == nterm_sym && s->class != nterm_sym)
s->number = nvars++;
else if (class == token_sym && s->number == NUMBER_UNDEFINED)
s->number = ntokens++;
sym->content->class = class;
if (declaring)
{
if (sym->content->status == declared && !warned)
complain (&loc, Wother, _("symbol %s redeclared"), sym->tag);
else
sym->content->status = declared;
if (declaring)
{
if (s->status == declared)
complain (&loc, Wother, _("symbol %s redeclared"), sym->tag);
else
s->status = declared;
}
}
}