111 lines
2.2 KiB
Plaintext
111 lines
2.2 KiB
Plaintext
% @doc a word is an ordset of ltrs
|
|
%
|
|
% This mathematically is a cluster of letters; so in "A + B + AB", this is one
|
|
% of the summands.
|
|
%
|
|
% multiplication is implied in a word
|
|
%
|
|
% empty word is 1
|
|
%
|
|
% anything times itself equals itself, so duplication is ignored
|
|
%
|
|
% multiplication = inclusive union
|
|
%
|
|
% operations assume all inputs are valid
|
|
-module(wfc_word).
|
|
|
|
-export_type([
|
|
word/0
|
|
]).
|
|
|
|
-export([
|
|
%% constructors
|
|
one/0,
|
|
validate/1,
|
|
from_list/1, to_list/1,
|
|
%% ops
|
|
mul/2, mul/1
|
|
]).
|
|
|
|
-opaque word() :: {w, ordsets:ordset(wfc_ltr:ltr())}.
|
|
|
|
%%----------------------------
|
|
%% constructor
|
|
%%----------------------------
|
|
|
|
-spec one() -> word().
|
|
|
|
one() ->
|
|
{w, []}.
|
|
|
|
|
|
-spec validate(Word) -> Result
|
|
when Word :: word(),
|
|
Result :: ok
|
|
| {error, Reason :: string()}.
|
|
% @doc
|
|
% check each letter in the word for validity
|
|
%
|
|
% also check that word shape is valid
|
|
% @end
|
|
|
|
validate(W = {w, Letters}) ->
|
|
case from_list(Letters) of
|
|
{ok, Result} when Result =:= W ->
|
|
ok;
|
|
Error ->
|
|
Error
|
|
end;
|
|
validate(X) ->
|
|
{error, wfc_utils:str("wfc_word:validate: malformed word: ~tp", [X])}.
|
|
|
|
|
|
|
|
-spec to_list(word()) -> Result
|
|
when Result :: {ok, [wfc_ltr:ltr()]}
|
|
| {error, string()}.
|
|
|
|
to_list({w, Ltrs}) -> {ok, Ltrs};
|
|
to_list(Bad) -> {error, wfc_utils:str("wfc_word:to_list: bad letter: ~tp", [Bad])}.
|
|
|
|
|
|
|
|
-spec from_list(Ltrs) -> Result
|
|
when Ltrs :: list(wfc_ltr:ltr()),
|
|
Result :: {ok, word()}
|
|
| {error, Reason :: string()}.
|
|
|
|
from_list(Chars) ->
|
|
from_list(ordsets:from_list(Chars), []).
|
|
|
|
|
|
%% validate each letter
|
|
from_list([Ltr | Rest], Acc) ->
|
|
case wfc_ltr:validate(Ltr) of
|
|
ok -> from_list(Rest, [Ltr | Acc]);
|
|
Error -> Error
|
|
end;
|
|
% done, all good
|
|
from_list([], Acc) ->
|
|
{ok, {w, lists:reverse(Acc)}}.
|
|
|
|
|
|
%%----------------------------
|
|
%% ops
|
|
%%----------------------------
|
|
|
|
-spec mul(word(), word()) -> word().
|
|
% @doc product of two words
|
|
%
|
|
% assumes the words are valid
|
|
|
|
mul({w, X}, {w, Y}) ->
|
|
{w, ordsets:union(X, Y)}.
|
|
|
|
|
|
-spec mul([word()]) -> word().
|
|
% @doc multiply a list of words together
|
|
|
|
mul([Word | Rest]) -> mul(Word, mul(Rest));
|
|
mul([]) -> one().
|