feat(calc)): partial supports of exp

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/elixir_math_parser.ex b/lib/elixir_math_parser.ex
index 863ecd8..b5e99bd 100644
--- a/lib/elixir_math_parser.ex
+++ b/lib/elixir_math_parser.ex
@@ -57,9 +57,32 @@ defmodule ElixirMathParser do
     end
   end
 
+  defp reduce_to_value({:exp_op, lhs, rhs}, state) do
+    with {:ok, op1} <- reduce_to_value(lhs, state),
+         {:ok, op2} <- reduce_to_value(rhs, state) do
+      if Ratio.denominator(op2) == 1 do
+        {:ok, expo(op1, Ratio.numerator(op2), 1)}
+      else
+        {:error, "unsupported operation"}
+      end
+    end
+  end
+
+  #  Functions for maths
+
   defp factor(n, acc) when n > 0, do: factor(n - 1, acc * n)
   defp factor(0, acc), do: acc
 
+  defp expo(value, exponent, acc) when exponent != 0 do
+    if exponent > 0 do
+      expo(value, exponent - 1, acc * value)
+    else
+      expo(value, exponent + 1, acc / value)
+    end
+  end
+
+  defp expo(_value, 0, acc), do: acc
+
   defp evaluate_tree([{:assign, {:var, line, lhs}, rhs} | tail], state) do
     with {:ok, val} <- reduce_to_value(rhs, state) do
       evaluate_tree(tail, Map.merge(state, %{lhs => val}))