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reader: get ready to create several initial rules

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* src/reader.c (create_start_rule): New.
Use it.
This commit is contained in:
Akim Demaille
2020-02-20 18:10:45 +01:00
parent f7f2c99c28
commit e50ec28153
1 changed files with 29 additions and 15 deletions
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44
src/reader.c
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@@ -764,6 +764,33 @@ find_start_symbol (void)
} }
/* Insert an initial rule, whose location is that of the first rule
(not that of the start symbol):
$accept: SWITCHING_TOKEN START $end. */
static void
create_start_rule (symbol *swtok, symbol *start)
{
symbol_list *initial_rule = symbol_list_sym_new (acceptsymbol, empty_loc);
initial_rule->rhs_loc = grammar->rhs_loc;
symbol_list *p = initial_rule;
if (swtok)
{
p->next = symbol_list_sym_new (swtok, empty_loc);
p = p->next;
}
p->next = symbol_list_sym_new (start, empty_loc);
p = p->next;
p->next = symbol_list_sym_new (eoftoken, empty_loc);
p = p->next;
p->next = symbol_list_sym_new (NULL, empty_loc);
p = p->next;
p->next = grammar;
nrules += 1;
nritems += 3 + !!swtok;
grammar = initial_rule;
}
/*-------------------------------------------------------------. /*-------------------------------------------------------------.
| Check the grammar that has just been read, and convert it to | | Check the grammar that has just been read, and convert it to |
| internal form. | | internal form. |
@@ -801,21 +828,8 @@ check_and_convert_grammar (void)
grammar_start_symbol_set (start, start->location); grammar_start_symbol_set (start, start->location);
} }
/* Insert the initial rule, whose line is that of the first rule /* Insert the initial rule. */
(not that of the start symbol): create_start_rule (NULL, startsymbol);
$accept: %start $end. */
{
symbol_list *p = symbol_list_sym_new (acceptsymbol, empty_loc);
p->rhs_loc = grammar->rhs_loc;
p->next = symbol_list_sym_new (startsymbol, empty_loc);
p->next->next = symbol_list_sym_new (eoftoken, empty_loc);
p->next->next->next = symbol_list_sym_new (NULL, empty_loc);
p->next->next->next->next = grammar;
nrules += 1;
nritems += 3;
grammar = p;
}
if (SYMBOL_NUMBER_MAXIMUM - nnterms < ntokens) if (SYMBOL_NUMBER_MAXIMUM - nnterms < ntokens)
complain (NULL, fatal, "too many symbols in input grammar (limit is %d)", complain (NULL, fatal, "too many symbols in input grammar (limit is %d)",