Support middle expressions on trim mode, closes #5752

Signed-off-by: José Valim <[email protected]>

Author: José Valim

lib/eex/lib/eex/compiler.ex

@@ -90,7 +90,9 @@ defmodule EEx.Compiler do
       {contents, start, list}
     end
   end
-
+  defp look_ahead_text([{:middle_expr, line, _, chars} | t], _start, contents) do
+    {contents ++ chars, line, t}
+  end
   defp look_ahead_text(t, start, contents) do
     {contents, start, t}
   end

lib/eex/lib/eex/tokenizer.ex

@@ -181,7 +181,6 @@ defmodule EEx.Tokenizer do
   # If trim mode is enabled and the token is on a line with
   # only itself and whitespace, trim the whitespace around it,
   # including the line break following it if there is one.
-
   defp trim_if_needed(rest, line, opts, buffer, acc) do
     original = {rest, line, buffer}
     if opts[:trim] do

lib/eex/test/eex_test.exs

@@ -331,6 +331,19 @@ foo
     assert_eval expected, string, [], trim: true
   end
 
+  test "trim mode with middle expression" do
+    string = """
+    <%= cond do %>
+    <% false -> %>
+      this
+    <% true -> %>
+      that
+    <% end %>
+    """
+    expected = "  that\n"
+    assert_eval expected, string, [], trim: true
+  end
+
   test "evaluates the source from a given file" do
     filename = Path.join(__DIR__, "fixtures/eex_template.eex")
     result = EEx.eval_file(filename)