In a new posting from Dynamically Typed today, Thomas Rutter talks about the support of multi-line strings in PHP (either just through assigning it or with something like heredoc), and a few examples of how they are supported in editors.

PHP conveniently allows two main methods of using multi-line strings, where a string constant is broken over many lines. However, it can be hard to find a syntax highlighting text editor that will correctly highlight multi-line strings in PHP.

When I was switched text editors recently, support for multi-line strings when syntax highlighting was high on my list of required features.

Some of the editors that he reviews for this feature include: Syn, TextPad, JEdit, and my personal choice, EditPlus. It looks like, unfortunately, that just about all of them don't understand how to correctly display multi-line strings. Of course, in the comments there are a few other suggestions - vim, SciTE, EmEditor, Emacs, and PHP Designer 2005.