Add Decimal.apply_context/1 and deprecate Decimal.plus/1 (ericmj#135)

lib/decimal.ex

@@ -939,12 +939,21 @@ defmodule Decimal do
   def negate(%Decimal{sign: sign} = num), do: context(%{num | sign: -sign})
   def negate(num), do: negate(decimal(num))
 
+  @doc false
+  @deprecated "Use Decimal.apply_context/1 instead"
+  def plus(decimal) do
+    apply_context(decimal)
+  end
+
   @doc """
   Applies the context to the given number rounding it to specified precision.
   """
-  @spec plus(t) :: t
-  def plus(%Decimal{coef: :sNaN} = num), do: error(:invalid_operation, "operation on NaN", num)
-  def plus(%Decimal{} = num), do: context(num)
+  doc_since("1.9.0")
+  @spec apply_context(t) :: t
+  def apply_context(%Decimal{coef: :sNaN} = num),
+    do: error(:invalid_operation, "operation on NaN", num)
+
+  def apply_context(%Decimal{} = num), do: context(num)
 
   @doc """
   Check if given number is positive

test/decimal_test.exs

@@ -468,16 +468,16 @@ defmodule DecimalTest do
     end
   end
 
-  test "plus/1" do
+  test "apply_context/1" do
     Decimal.with_context(%Context{precision: 2}, fn ->
-      assert Decimal.plus(~d"0") == d(1, 0, 0)
-      assert Decimal.plus(~d"5") == d(1, 5, 0)
-      assert Decimal.plus(~d"123") == d(1, 12, 1)
-      assert Decimal.plus(~d"nan") == d(1, :qNaN, 0)
+      assert Decimal.apply_context(~d"0") == d(1, 0, 0)
+      assert Decimal.apply_context(~d"5") == d(1, 5, 0)
+      assert Decimal.apply_context(~d"123") == d(1, 12, 1)
+      assert Decimal.apply_context(~d"nan") == d(1, :qNaN, 0)
     end)
 
     assert_raise Error, fn ->
-      Decimal.plus(~d"snan")
+      Decimal.apply_context(~d"snan")
     end
   end