opal/opal — pull request #526 by mieko (2014-04-04 10:20:00+00:00)
Title: Distinguish between single- and double-quoted heredoc identifiers.

Single-quoted heredoc identifiers do not process the content for escape sequences.

Added tests to ensure:
* Escapes not processed in `<<'EOD'`
* Escapes are processed in `<<"EOD"`
* `<