#include "list.h"
#include "ht.h"
#include "slr_table.h"

struct rule_s{
  NUM nt_num;
  NUM rule_num;
};

struct item_s {
  rule r;
  NUM pos;
};

struct item_set_s {
  /* a list of items */
  List *nonkernels;
  /* a list of nonterminal symbols: a kernel item for a nonterminal
     consists of all rules for that nonterminal, so we only need to
     store the nonterminal, which are represented as NUM's. */
  List *kernels;
};

typedef enum SLR_ACTION_e {
  SHIFT,
  REDUCE,
  ACCEPT,
  REJECT
} SLR_ACTION;

struct action_s {
  SLR_ACTION type;
  NUM arg1;
  NUM arg2;
};

struct slr_table_s {
  /* a list of states/rows

     Each row contains a hash table mapping non-terminals, terminals,
     and predicate terminals to an action set. */
  List *rows;
  /* a list of item sets; these are the states */
  List *states;
};

BOOL
closure(item_set *is, Grammar *g)
{
  NUM nonlen = list_length(is->nonkernels);

  for (NUM i = 0; i < nonlen; i++) {
    item it = *((item *)list_nth(is->nonkernels, i));
    List *tnts = grammar_rule(g, it.r.nt_num, it.r.rule_num);
    if (list_length(tnts) == 0) continue;

    NUM *temp = MYALLOC(NUM, 1);
    *temp = *((NUM *) list_nth(tnts, it.pos));

    if (add_to_list(is->kernels, temp)) {
      free(temp);
      fleprintf("Fail to add to list at i = %ld\n", i);
      return 1;
    }
  }

  return 0;
}