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h_predict for k>1, more debugging

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This commit is contained in:
Sven M. Hallberg 2013-05-24 01:31:56 +02:00
parent 748845ca0c
commit 428636f3d0
3 changed files with 58 additions and 43 deletions
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37
src/cfgrammar.c
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@ -437,7 +437,23 @@ static bool any_string_shorter(size_t k, const HCFStringMap *m)
return false;
}
const HCFStringMap *h_follow(size_t k, HCFGrammar *g, const HCFChoice *x);
// helper for h_predict
static void remove_all_shorter(size_t k, HCFStringMap *m)
{
if(k==0) return;
m->epsilon_branch = NULL;
if(k==1) return;
// iterate over m->char_branches
const HHashTable *ht = m->char_branches;
for(size_t i=0; i < ht->capacity; i++) {
for(HHashTableEntry *hte = &ht->contents[i]; hte; hte = hte->next) {
if(hte->key == NULL)
continue;
remove_all_shorter(k-1, hte->value); // recursion into subtree
}
}
}
// h_follow adapted to the signature of StringSetFun
static inline const HCFStringMap *h_follow_(size_t k, HCFGrammar *g, HCFChoice **s)
@ -507,6 +523,23 @@ const HCFStringMap *h_follow(size_t k, HCFGrammar *g, const HCFChoice *x)
return ret;
}
HCFStringMap *h_predict(size_t k, HCFGrammar *g,
const HCFChoice *A, const HCFSequence *rhs)
{
HCFStringMap *ret = h_stringmap_new(g->arena);
// predict_k(A -> rhs) =
// { ab | a <- first_k(rhs), b <- follow_k(A), |ab|=k }
const HCFStringMap *first_rhs = h_first_seq(k, g, rhs->items);
stringset_extend(g, ret, k, first_rhs, h_follow_, (HCFChoice **)&A);
// make sure there are only strings of length _exactly_ k
remove_all_shorter(k, ret);
return ret;
}
// add the set { a b | a <- as, b <- f_l(S), l=k-|a| } to ret
static void stringset_extend(HCFGrammar *g, HCFStringMap *ret,
size_t k, const HCFStringMap *as,
@ -806,7 +839,7 @@ pprint_stringset_elems(FILE *file, bool first, char *prefix, size_t n,
return first;
}
void h_pprint_stringset(FILE *file, const HCFGrammar *g, const HCFStringMap *set, int indent)
void h_pprint_stringset(FILE *file, const HCFStringMap *set, int indent)
{
int j;
for(j=0; j<indent; j++) fputc(' ', file);