diff options
Diffstat (limited to 'libguile/hashtab.c')
-rw-r--r-- | libguile/hashtab.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/libguile/hashtab.c b/libguile/hashtab.c index fc7fa424e..fff48b857 100644 --- a/libguile/hashtab.c +++ b/libguile/hashtab.c @@ -205,6 +205,7 @@ SCM_DEFINE (scm_hash_table_p, "hash-table?", 1, 0, 0, } #undef FUNC_NAME + /* Accessing hash table entries. */ @@ -966,6 +967,33 @@ SCM_DEFINE (scm_hash_map_to_list, "hash-map->list", 2, 0, 0, } #undef FUNC_NAME +static SCM +count_proc (void *pred, SCM key, SCM data, SCM value) +{ + if (scm_is_false (scm_call_2 (SCM_PACK (pred), key, data))) + return value; + else + return scm_oneplus(value); +} + +SCM_DEFINE (scm_hash_count, "hash-count", 2, 0, 0, + (SCM pred, SCM table), + "Return the number of elements in the given hash TABLE that\n" + "cause `(PRED KEY VALUE)' to return true. To quickly determine\n" + "the total number of elements, use `(const #t)' for PRED.") +#define FUNC_NAME s_scm_hash_count +{ + SCM init; + + SCM_VALIDATE_PROC (1, pred); + SCM_VALIDATE_HASHTABLE (2, table); + + init = scm_from_int (0); + return scm_internal_hash_fold ((scm_t_hash_fold_fn) count_proc, + (void *) SCM_UNPACK (pred), init, table); +} +#undef FUNC_NAME + SCM |