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[PATCH 2/4] style: clean up nullable
From: |
Akim Demaille |
Subject: |
[PATCH 2/4] style: clean up nullable |
Date: |
Fri, 26 Jun 2020 07:56:45 +0200 |
* src/nullable.c: Reduce scopes.
Prefer `r` to `rules_ruleno`, which is truly an ugly name.
---
src/nullable.c | 95 +++++++++++++++++++++++---------------------------
1 file changed, 44 insertions(+), 51 deletions(-)
diff --git a/src/nullable.c b/src/nullable.c
index 453b4e59..7d72c186 100644
--- a/src/nullable.c
+++ b/src/nullable.c
@@ -36,7 +36,7 @@
typedef struct rule_list
{
struct rule_list *next;
- rule *value;
+ const rule *value;
} rule_list;
bool *nullable = NULL;
@@ -44,9 +44,8 @@ bool *nullable = NULL;
static void
nullable_print (FILE *out)
{
- int i;
fputs ("NULLABLE\n", out);
- for (i = ntokens; i < nsyms; i++)
+ for (int i = ntokens; i < nsyms; i++)
fprintf (out, " %s: %s\n", symbols[i]->tag,
nullable[i - ntokens] ? "yes" : "no");
fputs ("\n\n", out);
@@ -55,12 +54,8 @@ nullable_print (FILE *out)
void
nullable_compute (void)
{
- rule_number ruleno;
- symbol_number *s1;
- symbol_number *s2;
- rule_list *p;
+ nullable = xcalloc (nvars, sizeof *nullable);
- symbol_number *squeue = xnmalloc (nvars, sizeof *squeue);
size_t *rcount = xcalloc (nrules, sizeof *rcount);
/* RITEM contains all the rules, including useless productions.
Hence we must allocate room for useless nonterminals too. */
@@ -69,54 +64,52 @@ nullable_compute (void)
Supposedly NRITEMS - NRULES is enough. But why take the risk? */
rule_list *relts = xnmalloc (nritems + nvars + 1, sizeof *relts);
- nullable = xcalloc (nvars, sizeof *nullable);
-
- s1 = s2 = squeue;
- p = relts;
-
- for (ruleno = 0; ruleno < nrules; ++ruleno)
- if (rules[ruleno].useful)
- {
- rule *rules_ruleno = &rules[ruleno];
- if (rules_ruleno->rhs[0] >= 0)
- {
- /* This rule has a non empty RHS. */
- item_number *rp = NULL;
- bool any_tokens = false;
- for (rp = rules_ruleno->rhs; *rp >= 0; ++rp)
- if (ISTOKEN (*rp))
- any_tokens = true;
-
- /* This rule has only nonterminals: schedule it for the second
- pass. */
- if (!any_tokens)
- for (rp = rules_ruleno->rhs; *rp >= 0; ++rp)
+ symbol_number *squeue = xnmalloc (nvars, sizeof *squeue);
+ symbol_number *s2 = squeue;
+ {
+ rule_list *p = relts;
+ for (rule_number ruleno = 0; ruleno < nrules; ++ruleno)
+ if (rules[ruleno].useful)
+ {
+ const rule *r = &rules[ruleno];
+ if (r->rhs[0] >= 0)
+ {
+ /* This rule has a non empty RHS. */
+ bool any_tokens = false;
+ for (item_number *rp = r->rhs; *rp >= 0; ++rp)
+ if (ISTOKEN (*rp))
+ any_tokens = true;
+
+ /* This rule has only nonterminals: schedule it for the second
+ pass. */
+ if (!any_tokens)
+ for (item_number *rp = r->rhs; *rp >= 0; ++rp)
+ {
+ rcount[ruleno]++;
+ p->next = rsets[*rp - ntokens];
+ p->value = r;
+ rsets[*rp - ntokens] = p;
+ p++;
+ }
+ }
+ else
+ {
+ /* This rule has an empty RHS. */
+ if (r->useful
+ && ! nullable[r->lhs->number - ntokens])
{
- rcount[ruleno]++;
- p->next = rsets[*rp - ntokens];
- p->value = rules_ruleno;
- rsets[*rp - ntokens] = p;
- p++;
+ nullable[r->lhs->number - ntokens] = true;
+ *s2++ = r->lhs->number;
}
- }
- else
- {
- /* This rule has an empty RHS. */
- aver (item_number_as_rule_number (rules_ruleno->rhs[0])
- == ruleno);
- if (rules_ruleno->useful
- && ! nullable[rules_ruleno->lhs->number - ntokens])
- {
- nullable[rules_ruleno->lhs->number - ntokens] = true;
- *s2++ = rules_ruleno->lhs->number;
- }
- }
- }
+ }
+ }
+ }
+ symbol_number *s1 = squeue;
while (s1 < s2)
- for (p = rsets[*s1++ - ntokens]; p; p = p->next)
+ for (rule_list *p = rsets[*s1++ - ntokens]; p; p = p->next)
{
- rule *r = p->value;
+ const rule *r = p->value;
if (--rcount[r->number] == 0)
if (r->useful && ! nullable[r->lhs->number - ntokens])
{
--
2.27.0