No longer trim by default when splitting

Further discussion here:

  https://groups.google.com/forum/#!topic/elixir-lang-core/66gb3J0bnUA

Author: vanstee

lib/elixir/lib/regex.ex

@@ -275,7 +275,7 @@ defmodule Regex do
     opts   = [return: return, parts: parts]
     splits = :re.split(string, compiled, opts)
 
-    if Keyword.get(options, :trim, true) do
+    if Keyword.get(options, :trim, false) do
       lc split inlist splits, split != "", do: split
     else
       splits

lib/elixir/lib/string.ex

@@ -163,17 +163,17 @@ defmodule String do
   The string is split into as many parts as possible by
   default, unless the `global` option is set to `false`.
 
-  Empty strings are removed from the result, unless the
-  `trim` option is set to `false`.
+  Empty strings are only removed from the result if the
+  `trim` option is set to `true`.
 
   ## Examples
 
       iex> String.split("a,b,c", ",")
       ["a", "b", "c"]
       iex> String.split("a,b,c", ",", global: false)
       ["a", "b,c"]
-      iex> String.split(" a b c ", " ", trim: false)
-      ["", "a", "b", "c", ""]
+      iex> String.split(" a b c ", " ", trim: true)
+      ["a", "b", "c"]
 
       iex> String.split("1,2 3,4", [" ", ","])
       ["1", "2", "3", "4"]
@@ -200,7 +200,7 @@ defmodule String do
     opts = if options[:global] != false, do: [:global], else: []
     splits  = :binary.split(binary, pattern, opts)
 
-    if Keyword.get(options, :trim, true) do
+    if Keyword.get(options, :trim, false) do
       lc split inlist splits, split != "", do: split
     else
       splits

lib/elixir/test/elixir/regex_test.exs

@@ -113,14 +113,14 @@ defmodule Regex.BinaryTest do
   end
 
   test :split do
-    assert Regex.split(%r",", "") == []
+    assert Regex.split(%r",", "") == [""]
     assert Regex.split(%r" ", "foo bar baz") == ["foo", "bar", "baz"]
     assert Regex.split(%r" ", "foo bar baz", parts: 2) == ["foo", "bar baz"]
     assert Regex.split(%r"\s", "foobar") == ["foobar"]
-    assert Regex.split(%r" ", "foo bar baz") == ["foo", "bar", "baz"]
-    assert Regex.split(%r" ", " foo bar baz ", trim: false) == ["", "foo", "bar", "baz", ""]
-    assert Regex.split(%r"=", "key=") == ["key"]
-    assert Regex.split(%r"=", "=value") == ["value"]
+    assert Regex.split(%r" ", " foo bar baz ") == ["", "foo", "bar", "baz", ""]
+    assert Regex.split(%r" ", " foo bar baz ", trim: true) == ["foo", "bar", "baz"]
+    assert Regex.split(%r"=", "key=") == ["key", ""]
+    assert Regex.split(%r"=", "=value") == ["", "value"]
   end
 
   test :replace do

lib/elixir/test/elixir/string_test.exs

@@ -29,21 +29,21 @@ defmodule StringTest do
     assert String.split("a,b,c", ",") == ["a", "b", "c"]
     assert String.split("a,b", ".") == ["a,b"]
     assert String.split("1,2 3,4", [" ", ","]) == ["1", "2", "3", "4"]
-    assert String.split(" a b c ", " ") == ["a", "b", "c"]
+    assert String.split(" a b c ", " ") == ["", "a", "b", "c", ""]
 
     assert String.split("a,b,c", ",", global: false) == ["a", "b,c"]
     assert String.split("1,2 3,4", [" ", ","], global: false) == ["1", "2 3,4"]
 
-    assert String.split(" a b c ", " ", trim: false) == ["", "a", "b", "c", ""]
-    assert String.split(" a b c ", " ", trim: false, global: false) == ["", "a b c "]
+    assert String.split(" a b c ", " ", trim: true) == ["a", "b", "c"]
+    assert String.split(" a b c ", " ", trim: true, global: false) == ["a b c "]
   end
 
   test :split_with_regex do
     assert String.split("", %r{,}) == [""]
     assert String.split("a,b", %r{,}) == ["a", "b"]
     assert String.split("a,b,c", %r{,}) == ["a", "b", "c"]
     assert String.split("a,b,c", %r{,}, global: false) == ["a", "b,c"]
-    assert String.split("a,b.c ", %r{\W}) == ["a", "b", "c"]
+    assert String.split("a,b.c ", %r{\W}) == ["a", "b", "c", ""]
     assert String.split("a,b.c ", %r{\W}, trim: false) == ["a", "b", "c", ""]
     assert String.split("a,b", %r{\.}) == ["a,b"]
   end