Basic "<<"-style heredoc indenting

If the closing delimiter is at column 0, keep it that way.

indent/ruby.vim

@@ -124,6 +124,11 @@ function s:IsInStringOrDocumentation(lnum, col)
   return synIDattr(synID(a:lnum, a:col, 1), 'name') =~ s:syng_stringdoc
 endfunction
 
+" Check if the character at lnum:col is inside a string delimiter
+function s:IsInStringDelimiter(lnum, col)
+  return synIDattr(synID(a:lnum, a:col, 1), 'name') == 'rubyStringDelimiter'
+endfunction
+
 " Find line above 'lnum' that isn't empty, in a comment, or in a string.
 function s:PrevNonBlankNonString(lnum)
   let in_block = 0
@@ -376,6 +381,14 @@ function GetRubyIndent(...)
     return indent('.')
   endif
 
+  " If we are at the closing delimiter of a "<<" heredoc-style string, set the
+  " indent to 0.
+  if line =~ '^\k\+\s*$'
+        \ && s:IsInStringDelimiter(clnum, 1)
+        \ && search('\V<<'.line, 'nbW') > 0
+    return 0
+  endif
+
   " 3.3. Work on the previous line. {{{2
   " -------------------------------
 

spec/indent/basic_spec.rb

@@ -21,4 +21,22 @@
       something_else
     EOF
   end
+
+  specify "heredocs" do
+    assert_correct_indenting <<-EOF
+      def one
+        two = <<-THREE
+        four
+        THREE
+      end
+    EOF
+
+    assert_correct_indenting <<-EOF
+      def one
+        two = <<THREE
+      four
+      THREE
+      end
+    EOF
+  end
 end