Move logic for multi rolls

lib/cli.ex

@@ -147,7 +147,7 @@ defmodule ExTTRPGDev.CLI do
 
   def handle_roll(%Optimus.ParseResult{args: %{dice: dice}}) do
     dice
-    |> Enum.map(fn dice_spec -> {dice_spec, Dice.roll(dice_spec)} end)
+    |> Dice.multi_roll!()
     |> Enum.each(fn {dice_spec, results} -> IO.inspect(results, label: dice_spec) end)
   end
 

lib/dice.ex

@@ -27,6 +27,29 @@ defmodule ExTTRPGDev.Dice do
     str
   end
 
+  @doc """
+  Tries to parse a given dice spec string into it's component parts
+
+  Returns: a tuple where the first item is the number of times to roll the die and the second indicates the  number or sides the die has
+
+  ## Examples
+
+      iex> ExTTRPGDev.Dice.parse_roll_spec!("3d4")
+      {3, 4}
+
+      iex> ExTTRPGDev.Dice.parse_roll_spec!("3")
+      ** (RuntimeError) Improper dice format. Dice must be given in xdy where x and y are both integers
+
+  """
+
+  def parse_roll_spec!(roll_spec) when is_bitstring(roll_spec) do
+    roll_spec
+    |> validate_dice_str()
+    |> String.split("d")
+    |> Enum.map(fn x -> String.to_integer(x) end)
+    |> List.to_tuple()
+  end
+
   @doc """
   Rolls the a number of multisided dice
 
@@ -39,32 +62,51 @@ defmodule ExTTRPGDev.Dice do
       iex> ExTTRPGDev.Dice.roll(3, 8)
       [4, 8, 5]
 
+      iex> :rand.seed(:exsplus, 1337)
+      iex> ExTTRPGDev.Dice.roll({3, 8})
+      [4, 8, 5]
+
+      iex> :rand.seed(:exsplus, 1337)
+      iex> ExTTRPGDev.Dice.roll("3d8")
+      [4, 8, 5]
+
+      iex> ExTTRPGDev.Dice.roll("bad_input")
+      ** (RuntimeError) Improper dice format. Dice must be given in xdy where x and y are both integers
+
   """
+  def roll(str) when is_bitstring(str) do
+    {number_of_dice, sides} = parse_roll_spec!(str)
+    roll(number_of_dice, sides)
+  end
+
+  def roll({number_of_dice, sides}), do: roll(number_of_dice, sides)
+
   def roll(number_of_dice, dice_sides) do
     Enum.map(1..number_of_dice, fn _ -> roll_d(dice_sides) end)
   end
 
   @doc """
-  Roll dice defined by the input string
+  Roll multiple roll specs
 
-  Returns: List of die roll results
+  Returns: List of tuples, the first value being the roll spec, the second being the results
 
   ## Examples
-
       # Although not necessary, let's seed the random algorithm
       iex> :rand.seed(:exsplus, 1337)
-      iex> ExTTRPGDev.Dice.roll("3d4")
-      [4, 4, 1]
+      iex> ExTTRPGDev.Dice.multi_roll!(["3d4", "4d8", "2d20"])
+      [{"3d4", [4, 4, 1]}, {"4d8", [1, 3, 5, 6]}, {"2d20", [5, 12]}]
 
-  """
-  def roll(str) when is_bitstring(str) do
-    [number_of_dice, sides] =
-      str
-      |> validate_dice_str()
-      |> String.split("d")
-      |> Enum.map(fn x -> String.to_integer(x) end)
+      iex> :rand.seed(:exsplus, 1337)
+      iex> ExTTRPGDev.Dice.multi_roll!([{3, 4}, {4, 8}, {2, 20}])
+      [{{3, 4}, [4, 4, 1]}, {{4, 8}, [1, 3, 5, 6]}, {{2, 20}, [5, 12]}]
 
-    roll(number_of_dice, sides)
+      iex> ExTTRPGDev.Dice.multi_roll!(["bad_spec", "oh_no!", "3d4"])
+      ** (RuntimeError) Improper dice format. Dice must be given in xdy where x and y are both integers
+
+  """
+  def multi_roll!(roll_specs) when is_list(roll_specs) do
+    roll_specs
+    |> Enum.map(fn roll_spec -> {roll_spec, roll(roll_spec)} end)
   end
 
   @doc """