Cleaning up the handling of character turns.

1 files changed, 45 insertions, 0 deletions

diff --git a/src/struct/location.erl b/src/struct/location.erl
new file mode 100644
index 0000000..624fe56
--- /dev/null
+++ b/src/struct/location.erl
@@ -0,0 +1,45 @@
+-module(location).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% TYPES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-type type() :: {non_neg_integer(), non_neg_integer()}.
+
+-export_type([type/0]).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% EXPORTS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-export
+(
+   [
+      apply_direction/2,
+      dist/2
+   ]
+).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% LOCAL FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-spec validate ({integer(), integer()}) -> type().
+validate ({X, Y}) ->
+   true = (X >= 0),
+   true = (Y >= 0),
+   {X, Y}.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% EXPORTED FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-spec apply_direction (direction:enum(), type()) -> type().
+apply_direction (left, {X, Y}) ->
+   validate({(X - 1), Y});
+apply_direction (right, {X, Y}) ->
+   validate({(X + 1), Y});
+apply_direction (up, {X, Y}) ->
+   validate({X, (Y - 1)});
+apply_direction (down, {X, Y}) ->
+   validate({X, (Y + 1)}).
+
+-spec dist(type(), type()) -> non_neg_integer().
+dist ({OX, OY}, {DX, DY}) ->
+   (abs(DY - OY) + abs(DX - OX)).