Skip any blank lines at the beginning of template

lib/slime/parser/transform.ex

@@ -33,9 +33,9 @@ defmodule Slime.Parser.Transform do
   @spec transform(atom, iolist, index) :: ast
   def transform(:document, input, _index) do
     case input do
-      [[], tags | _] -> tags
-      [doctype, [""] | _] -> [doctype]
-      [doctype, tags | _] -> [doctype | tags]
+      [_blank_lines, [], tags | _] -> tags
+      [_blank_lines, doctype, [""] | _] -> [doctype]
+      [_blank_lines, doctype, tags | _] -> [doctype | tags]
     end
   end
 

src/slime_parser.peg.eex

@@ -1,4 +1,4 @@
-document <- doctype? tags? eof;
+document <- (space? crlf)* doctype? tags? eof;
 
 doctype <- space? 'doctype' space name:(!eol .)+ eol;
 

test/renderer_test.exs

@@ -122,4 +122,13 @@ defmodule RendererTest do
     assert render(example_unix) == expected_rendered_output
     assert render(example_windows) == expected_rendered_output
   end
+
+  test "template can start with an empty line" do
+    slime = """
+
+    div test
+    """
+
+    assert render(slime) == "<div>test</div>"
+  end
 end