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| author | Brett Snyder <bsnyder@digitalocean.com> | 2019-05-14 18:20:32 -0500 |
|---|---|---|
| committer | Louis Pilfold <louis@lpil.uk> | 2019-05-15 17:32:50 +0100 |
| commit | af07c099e69e296aaeabeebcb3e0a304bcb24d1d (patch) | |
| tree | a0b298ed1f2d227713d23c6643cb05a4bdf73273 /gen | |
| parent | 1c16eee098e36ed322450fe7c048701df466978e (diff) | |
| download | gleam_stdlib-af07c099e69e296aaeabeebcb3e0a304bcb24d1d.tar.gz gleam_stdlib-af07c099e69e296aaeabeebcb3e0a304bcb24d1d.zip | |
map_dict:fold
Diffstat (limited to 'gen')
| -rw-r--r-- | gen/src/map_dict.erl | 12 | ||||
| -rw-r--r-- | gen/test/map_dict_test.erl | 13 |
2 files changed, 23 insertions, 2 deletions
diff --git a/gen/src/map_dict.erl b/gen/src/map_dict.erl index 10150b3..e72b92d 100644 --- a/gen/src/map_dict.erl +++ b/gen/src/map_dict.erl @@ -1,7 +1,7 @@ -module(map_dict). -compile(no_auto_import). --export([size/1, to_list/1, from_list/1, has_key/2, new/0, fetch/2, put/3, map_values/2, keys/1, values/1, filter/2, take/2, merge/2, delete/2, drop/2, update/3]). +-export([size/1, to_list/1, from_list/1, has_key/2, new/0, fetch/2, put/3, map_values/2, keys/1, values/1, filter/2, take/2, merge/2, delete/2, drop/2, update/3, fold/3]). size(A) -> maps:size(A). @@ -74,3 +74,13 @@ update(Dict, Key, F) -> {error, _} -> put(Dict, Key, F({error, not_found})) end. + +fold(Dict, Acc, F) -> + Kvs = to_list(Dict), + case Kvs of + [] -> + Acc; + + [{K, V} | _] -> + fold(delete(Dict, K), F(K, V, Acc), F) + end. diff --git a/gen/test/map_dict_test.erl b/gen/test/map_dict_test.erl index 24255f1..03be65a 100644 --- a/gen/test/map_dict_test.erl +++ b/gen/test/map_dict_test.erl @@ -1,7 +1,7 @@ -module(map_dict_test). -compile(no_auto_import). --export([from_list_test/0, has_key_test/0, new_test/0, fetch_test/0, put_test/0, map_values_test/0, keys_test/0, values_test/0, take_test/0, drop_test/0, merge_test/0, delete_test/0, update_test/0]). +-export([from_list_test/0, has_key_test/0, new_test/0, fetch_test/0, put_test/0, map_values_test/0, keys_test/0, values_test/0, take_test/0, drop_test/0, merge_test/0, delete_test/0, update_test/0, fold_test/0]). from_list_test() -> expect:equal(map_dict:size(map_dict:from_list([{4, 0}, {1, 0}])), 2). @@ -115,3 +115,14 @@ update_test() -> {<<"b">>, 1}, {<<"c">>, 2}, {<<"z">>, 0}])). + +fold_test() -> + Dict = map_dict:from_list([{<<"a">>, 0}, + {<<"b">>, 1}, + {<<"c">>, 2}, + {<<"d">>, 3}]), + Add = fun(_, V, Acc) -> V + Acc end, + expect:equal(map_dict:fold(Dict, 0, Add), 6), + Concat = fun(K, _, Acc) -> str:append(Acc, K) end, + expect:equal(map_dict:fold(Dict, <<"">>, Concat), <<"abcd">>), + expect:equal(map_dict:fold(map_dict:from_list([]), 0, Add), 0). |