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#include "grammar.h"
struct TNT_s {
int type; /* 0 => T and NT otherwise */
union { T t; NT nt; } data;
};
struct Rule_s {
NT left;
List *right;
};
struct Grammar_s {
List *rules;
/* a list of names of non-terminals */
List *names;
};
TNT *
new_tnt(int type, ...)
{
va_list args;
va_start(args, type);
TNT *result = MYALLOC(TNT, 1);
result->type = type;
if (type) result->data.nt = va_arg(args, NT);
else result->data.t = va_arg(args, T);
va_end(args);
return result;
}
Rule *
new_rule(NT left, List *right)
{
if (!right) return NULL;
Rule *rule = MYALLOC(Rule, 1);
rule->left = left;
rule->right = right;
return rule;
}
Grammar *
new_grammar()
{
Grammar *g = MYALLOC(Grammar, 1);
return g;
}
void
build_grammar(Grammar *g, List *rules, List *names)
{
g->rules = rules;
g->names = names;
}
void
print_tnt(void *element)
{
TNT *tnt = (TNT*) element;
if (tnt->type)
printf("NT %u, ", tnt->data.nt);
else
printf("T %lu, ", tnt->data.t);
}
void
print_rule(void *r)
{
Rule *rule = (Rule *) r;
printf("Rule: %u => ", rule->left);
map_list(rule->right, print_tnt);
printf("\n");
}
/* a local function pointer */
void
print_name(void *element)
{
char *str = (char *) element;
printf("%s", str);
}
/* a local function pointer */
void
print_sep()
{
printf(", ");
}
void
print_grammar(Grammar *g)
{
printf("Printing a grammar:\n");
map_list_between(g->names, print_name, print_sep);
printf("\n");
map_list(g->rules, print_rule);
printf("\n");
}
List *
new_tnt_string(char *format, int format_len, ...)
{
/* FORMAT_LEN does not include the terminating null byte, so it
should be > 0. */
if (format_len <= 0) return NULL;
List *result = new_list();
va_list args;
va_start(args, format_len);
for (int point = 0; point < format_len; point++) {
switch (*(format+point)) {
case 'n':
add_to_list(result, new_tnt(1, va_arg(args, NT)));
break;
case 't':
add_to_list(result, new_tnt(0, va_arg(args, T)));
break;
default:
eprintf("Wront character: %c\n", *(format+point));
destroy_list(result, 1);
va_end(args);
return NULL;
break;
}
}
va_end(args);
return result;
}
void
destroy_rule(void *rule, int flag)
{
Rule * r = (Rule *) rule;
destroy_list(r->right, flag);
free(rule);
}
void
destroy_rule_and_free_all(void *rule)
{
destroy_rule(rule, 1);
}
void
destroy_rule_and_free_first(void *rule)
{
destroy_rule(rule, 2);
}
void
destroy_rule_no_free(void *rule)
{
destroy_rule(rule, 0);
}
void
destroy_grammar(void *grammar, int flag)
{
Grammar *g = (Grammar *) grammar;
switch (flag) {
case 0:
map_list(g->rules, destroy_rule_no_free);
break;
case 1:
map_list(g->rules, destroy_rule_and_free_all);
break;
default:
map_list(g->rules, destroy_rule_and_free_first);
break;
}
destroy_list(g->rules, 0);
destroy_list(g->names, flag);
}
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