From 70d7a28a36098285646a461ff4170d412c7ac1b5 Mon Sep 17 00:00:00 2001
From: Justin Jaffray <justin.jaffray@gmail.com>
Date: Wed, 25 Dec 2013 10:35:24 -0500
Subject: [PATCH 1/2] Fix Float.parse to handle numbers of the form "-0.x"

Since Float.parse uses Integer.parse, the -0 would be
parsed independently of what came after the decimal
point and would become 0
---
 lib/elixir/lib/float.ex               | 9 +++++++++
 lib/elixir/test/elixir/float_test.exs | 1 +
 2 files changed, 10 insertions(+)

diff --git a/lib/elixir/lib/float.ex b/lib/elixir/lib/float.ex
index ca273a68a4a..fc8d9145673 100644
--- a/lib/elixir/lib/float.ex
+++ b/lib/elixir/lib/float.ex
@@ -22,6 +22,15 @@ defmodule Float do
 
   """
   @spec parse(binary) :: { float, binary } | :error
+
+  # Integer.parse will parse "-0" as 0, so it needs to be handled separately
+  def parse(<< "-0.", rest :: binary >>) do
+    case parse(<< ?., rest :: binary >>, 0) do
+      :error -> :error
+      { parsed, remainder } -> { -parsed, remainder }
+    end
+  end
+
   def parse(binary) when is_binary(binary) do
     case Integer.parse binary do
       :error -> :error
diff --git a/lib/elixir/test/elixir/float_test.exs b/lib/elixir/test/elixir/float_test.exs
index c42393b0cba..3396beb7f0d 100644
--- a/lib/elixir/test/elixir/float_test.exs
+++ b/lib/elixir/test/elixir/float_test.exs
@@ -6,6 +6,7 @@ defmodule FloatTest do
   test :parse do
     assert Float.parse("12") === {12.0, ""}
     assert Float.parse("-12") === {-12.0, ""}
+    assert Float.parse("-0.1") === {-0.1, ""}
     assert Float.parse("123456789") === {123456789.0, ""}
     assert Float.parse("12.5") === {12.5, ""}
     assert Float.parse("12.524235") === {12.524235, ""}

From 8c6e31bda09a07bbc90fa9c58644865d4af8d129 Mon Sep 17 00:00:00 2001
From: Justin Jaffray <justin.jaffray@gmail.com>
Date: Wed, 25 Dec 2013 13:25:36 -0500
Subject: [PATCH 2/2] Pattern match just on "-"

---
 lib/elixir/lib/float.ex | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/lib/elixir/lib/float.ex b/lib/elixir/lib/float.ex
index fc8d9145673..7349c7f4e49 100644
--- a/lib/elixir/lib/float.ex
+++ b/lib/elixir/lib/float.ex
@@ -22,37 +22,40 @@ defmodule Float do
 
   """
   @spec parse(binary) :: { float, binary } | :error
-
-  # Integer.parse will parse "-0" as 0, so it needs to be handled separately
-  def parse(<< "-0.", rest :: binary >>) do
-    case parse(<< ?., rest :: binary >>, 0) do
+  def parse("-" <> binary) do
+    case parse_unsign(binary) do
       :error -> :error
-      { parsed, remainder } -> { -parsed, remainder }
+      { number, remainder } -> { -number, remainder }
     end
   end
 
-  def parse(binary) when is_binary(binary) do
+  def parse(binary) do
+    parse_unsign(binary)
+  end
+
+  defp parse_unsign("-" <> binary), do: :error
+  defp parse_unsign(binary) when is_binary(binary) do
     case Integer.parse binary do
       :error -> :error
-      { integer_part, after_integer } -> parse after_integer, integer_part
+      { integer_part, after_integer } -> parse_unsign after_integer, integer_part
     end
   end
 
   # Dot followed by digit is required afterwards or we are done
-  defp parse(<< ?., char, rest :: binary >>, int) when char in ?0..?9 do
-    parse(rest, char - ?0, 1, int)
+  defp parse_unsign(<< ?., char, rest :: binary >>, int) when char in ?0..?9 do
+    parse_unsign(rest, char - ?0, 1, int)
   end
 
-  defp parse(rest, int) do
+  defp parse_unsign(rest, int) do
     { :erlang.float(int), rest }
   end
 
   # Handle decimal points
-  defp parse(<< char, rest :: binary >>, float, decimal, int) when char in ?0..?9 do
-    parse rest, 10 * float + (char - ?0), decimal + 1, int
+  defp parse_unsign(<< char, rest :: binary >>, float, decimal, int) when char in ?0..?9 do
+    parse_unsign rest, 10 * float + (char - ?0), decimal + 1, int
   end
 
-  defp parse(<< ?e, after_e :: binary >>, float, decimal, int) do
+  defp parse_unsign(<< ?e, after_e :: binary >>, float, decimal, int) do
     case Integer.parse after_e do
       :error ->
         # Note we rebuild the binary here instead of breaking it apart at
@@ -65,7 +68,7 @@ defmodule Float do
     end
   end
 
-  defp parse(bitstring, float, decimal, int) do
+  defp parse_unsign(bitstring, float, decimal, int) do
     { floatify(int, float, decimal), bitstring }
   end