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Allow %start after the first rule.

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* src/reader.c (grammar_current_rule_begin): Don't set the start symbol
when parsing the first rule.
(check_and_convert_grammar): Search for it here after all grammar
declarations have been parsed.  Skip midrules, which have dummy LHS
nonterminals.
* src/symtab.c (symbol_is_dummy): New function.
* src/symtab.h (symbol_is_dummy): Declare it.
* tests/input.at (%start after first rule): New test.
This commit is contained in:
Joel E. Denny
2006-08-20 03:10:18 +00:00
parent 6d0ef4ec20
commit 4d7370cb4f
5 changed files with 58 additions and 7 deletions
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24
src/reader.c
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@@ -225,13 +225,6 @@ static symbol_list *previous_rule_end = NULL;
void
grammar_current_rule_begin (symbol *lhs, location loc)
{
if (!start_flag)
{
startsymbol = lhs;
startsymbol_location = loc;
start_flag = true;
}
/* Start a new rule and record its lhs. */
++nrules;
previous_rule_end = grammar_end;
@@ -607,6 +600,23 @@ check_and_convert_grammar (void)
endtoken->user_token_number = 0;
}
/* Find the start symbol if no %start. */
if (!start_flag)
{
symbol_list *node;
for (node = grammar;
node != NULL && symbol_is_dummy (node->sym);
node = node->next)
{
for (node = node->next;
node != NULL && node->sym != NULL;
node = node->next)
;
}
assert (node != NULL);
grammar_start_symbol_set (node->sym, node->sym->location);
}
/* Insert the initial rule, whose line is that of the first rule
(not that of the start symbol):