Erlang Path

assignments/erlang/anagram/example.erl

@@ -1,4 +1,4 @@
--module(anagram).
+-module(example).
 -export([find/2]).
 
 -spec find(string(), [string()]) -> [string()].

assignments/erlang/bob/bob_tests.erl

@@ -0,0 +1,43 @@
+-module(bob_tests).
+
+-include_lib("eunit/include/eunit.hrl").
+
+responds_to_something_test() ->
+    bob_responds("Tom-ay-to, tom-aaaah-to.", "Whatever.").
+
+responds_to_shouts_test() ->
+    bob_responds("WATCH OUT!", "Woah, chill out!").
+
+responds_to_questions_test() ->
+    bob_responds("Does this cryogenic chamber make me look fat?", "Sure.").
+
+responds_to_forceful_talking_test() ->
+    bob_responds("Let's go make out behind the gym!", "Whatever.").
+
+responds_to_acronyms_test() ->
+    bob_responds("It's OK if you don't want to go to the DMV.", "Whatever.").
+
+responds_to_forceful_questions_test() ->
+    bob_responds("WHAT THE HELL WERE YOU THINKING?", "Woah, chill out!").
+
+responds_to_shouting_with_special_characters_test() ->
+    bob_responds("ZOMG THE %^*@#$(*^ ZOMBIES ARE COMING!!11!!1!", "Woah, chill out!").
+
+responds_to_shouting_numbers_test() ->
+    bob_responds("1, 2, 3, GO!", "Woah, chill out!").
+
+responds_to_shouting_with_no_exclamation_mark_test() ->
+    bob_responds("I HATE YOU", "Woah, chill out!").
+
+responds_to_statement_containing_question_mark_test() ->
+    bob_responds("Ending with ? means a question", "Whatever.").
+
+responds_to_silence_test() ->
+    bob_responds("", "Fine. Be that way.").
+
+responds_to_prolonged_silence_test() ->
+    bob_responds("    ", "Fine. Be that way.").
+
+bob_responds(Question, Answer) ->
+    ?assertEqual(bob:response_for(Question),
+                  Answer).

assignments/erlang/grade-school/example.erl

@@ -0,0 +1,23 @@
+-module(grade_school).
+
+-export([add/3, get/2, sort/1]).
+
+-spec add(string(), integer(), dict()) -> dict().
+add(Name, Grade, Students) ->
+    case orddict:find(Grade, Students) of
+        {ok, Class} ->
+            orddict:store(Grade, lists:sort([Name | Class]), Students);
+        error ->
+            orddict:store(Grade, [Name], Students)
+    end.
+
+-spec get(integer(), dict()) -> [string()].
+get(Grade, Students) ->
+    case orddict:find(Grade, Students) of
+        {ok, Class} -> Class;
+        _ -> []
+    end.
+
+-spec sort(dict()) -> dict().
+sort(S) ->
+    S.

assignments/erlang/grade-school/grade_school_tests.erl

@@ -0,0 +1,48 @@
+% To run tests:
+% elc *.erl
+% erl -noshell -eval "eunit:test(grade_school), [verbose])" -s init stop
+%
+
+% use a dict with keys for each grade and a list of the students within that grade.
+%  [{'grade-1', ['bill']}, {'grade-2', ['george', 'fred']]
+-module(grade_school_tests).
+
+-include_lib("eunit/include/eunit.hrl").
+
+%% Using proplists
+add_student_test() ->
+    ?assertEqual(grade_school:add("Aimee", 2, []),
+                 [{2, ["Aimee"]}]
+                ).
+
+add_more_students_in_same_class_test() ->
+    S1 = grade_school:add("James", 2, []),
+    S2 = grade_school:add("Blair", 2, S1),
+    S3 = grade_school:add("Paul", 2, S2),
+    ?assertEqual(S3, [{2, ["Blair","James","Paul"]}]).
+
+add_students_to_different_grades_test() ->
+    S1 = grade_school:add("Chelsea", 3, []),
+    S2 = grade_school:add("Logan", 7, S1),
+    ?assertEqual(S2, [{3, ["Chelsea"]}, {7, ["Logan"]}]).
+
+get_students_in_a_grade_test() ->
+    S1 = grade_school:add("Franklin", 5, []),
+    S2 = grade_school:add("Bradley", 5, S1),
+    S3 = grade_school:add("Jeff", 1, S2),
+    ?assertEqual(grade_school:get(5, S3), ["Bradley","Franklin"]).
+
+get_students_in_a_non_existant_grade_test() ->
+    ?assertEqual([], grade_school:get(1, [])).
+
+sort_school_test() ->
+    S1 = grade_school:add("Jennifer", 4, []),
+    S2 = grade_school:add("Kareem", 6, S1),
+    S3 = grade_school:add("Christopher", 4, S2),
+    S4 = grade_school:add("Kyle", 3, S3),
+
+    Sorted = [{3, ["Kyle"]},
+              {4, ["Christopher", "Jennifer"]},
+              {6, ["Kareem"]}],
+
+    ?assertEqual(Sorted, grade_school:sort(S4)).

assignments/erlang/point-mutations/dna_tests.erl

@@ -1,3 +1,31 @@
 -module(dna_tests).
 
 -include_lib("eunit/include/eunit.hrl").
+
+no_difference_between_empty_strands_test() ->
+    ?assertEqual(dna:hamming_distance("", ""), 0).
+
+no_dofference_between_identical_strands_test() ->
+    ?assertEqual(dna:hamming_distance("GGACTGA", "GGACTGA"), 0).
+
+complete_hamming_distance_in_small_strang_test() ->
+    ?assertEqual(dna:hamming_distance("ACT", "GGA"), 3).
+
+hamming_distance_in_off_by_one_strand_test() ->
+    ?assertEqual(dna:hamming_distance("GGACGGATTCTGACCTGGACTAATTTTGGGG",
+                                      "AGGACGGATTCTGACCTGGACTAATTTTGGGG"), 19).
+
+small_hamming_distance_in_middle_somewhere_test() ->
+    ?assertEqual(dna:hamming_distance("GGACG", "GGTCG"), 1).
+
+larger_distance_test() ->
+    ?assertEqual(dna:hamming_distance("ACCAGGG", "ACTATGG"), 2).
+
+ignores_extra_length_on_other_strand_when_longer_test() ->
+    ?assertEqual(dna:hamming_distance("GACTACGGACAGGGTAGGGAAT", "GACATCGCACACC"), 5).
+
+does_not_actually_shorten_original_strand_test() ->
+    ?assertEqual(dna:hamming_distance("AGACAACAGCCAGCCGCCGGATT", "AGGCAA"), 1),
+    ?assertEqual(dna:hamming_distance("AGACAACAGCCAGCCGCCGGATT", "AGGCAA"), 1),
+    ?assertEqual(dna:hamming_distance("AGACAACAGCCAGCCGCCGGATT", "AGACATCTTTCAGCCGCCGGATTAGGCAA"), 4),
+    ?assertEqual(dna:hamming_distance("AGACAACAGCCAGCCGCCGGATT", "AGG"), 1).

assignments/erlang/point-mutations/example.erl

@@ -0,0 +1,15 @@
+-module(dna).
+
+-export([hamming_distance/2]).
+
+hamming_distance(From, To) ->
+    % Make both lists the same length, as zipwith expects them to be.
+    ToPrime = lists:sublist(To, length(From)),
+    FromPrime = lists:sublist(From, length(To)),
+    Comparisons = lists:zipwith(fun(X,Y) -> case X =:= Y of
+                                          true -> 0;
+                                          false -> 1
+                                      end
+                          end,
+                          FromPrime, ToPrime),
+    lists:sum(Comparisons).

assignments/erlang/word-count/example2.erl

@@ -0,0 +1,17 @@
+-module(word_count).
+-export([count/1]).
+
+
+
+count(WordList) when is_list(WordList)->
+  count(string:tokens(lists:flatten(WordList), " "), dict:new()).
+
+
+
+%% Alternative shorter implementation using dict that doesn't preserve key order
+
+count([], Tally) ->
+  lists:flatten([io_lib:format("~s: ~B\n", [Word, Count]) || {Word, Count} <- dict:to_list(Tally)]);
+
+count([Word|Words], Tally) ->
+  count(Words, dict:update(Word, fun(Count) -> Count + 1 end, 1, Tally)).

lib/app/views/setup/erlang.erb

@@ -0,0 +1,11 @@
+<h3>Erlang</h3>
+
+<h4>Installation: </h4>
+
+<p>
+  Download and install a recent Erlang/OTP release for your OS from
+  <a href="http://www.erlang.org/download.html">erlang.org</a>.
+</p>
+
+<h4>Building and running tests: </h4>
+<pre>$ erl -make && erl -noshell -eval 'init:stop(case bob_tests:test() of ok -> 0; _ -> 1 end).'</pre>

lib/exercism/curriculum/erlang.rb

@@ -3,9 +3,9 @@ class ErlangCurriculum
     def slugs
       %w(
         bob rna-transcription word-count anagram beer-song
+        nucleotide-count point-mutations phone-number grade-school
       )
-        # nucleotide-count point-mutations phone-number
-        # grade-school robot-name leap etl meetup space-age grains
+        # robot-name leap etl meetup space-age grains
         # gigasecond triangle scrabble-score roman-numerals
         # binary prime-factors raindrops allergies
         # atbash-cipher